ALBERT

Description: We present a five-year (1997-2001) numerical simulation of daily mean chlorophyll a concentrations at station Geesthacht Weir on the lower Elbe River (Germany) using an extremely simple Lagrangian model driven by (a) water discharge, global radiation, water temperature, and (b) silica observations at station Schmilka in the upper reach of the Elbe River. Notwithstanding the lack of many mechanistic details, the model is able to reproduce observed chlorophyll a variability surprisingly well, including a number of sharp valleys and ascents/descents in the observed time series. The model's success is based on the assumption of three key effects: prevailing light conditions, sporadic limitation of algal growth due to lack of silica and algae loss rates that increase above an empirically specified temperature threshold of 20 degrees C. Trimmed-down model versions are studied to analyse the model's success in terms of these mechanisms. In each of the five years the model consistently fails, however, to properly simulate characteristic steep increases of chlorophyll a concentrations after pronounced spring minima. Curing this model deficiency by global model re-calibration was found to be impossible. However, suspension of silica consumption by algae for up to 10 days in spring is shown to serve as a successful placeholder for processes that are disregarded in the model but apparently play an important role in the distinctly marked period of model failure. For the remainder of the year the very simple model was found to be adequate

Description: A simple Lagrangian water quality model was designed to investigate the hypothesis of sporadic silica limitations of diatom growth in the lower Elbe River in Germany. For each fluid parcel a limited reservoir of silica was specified to be consumed by diatoms. The model's simplicity notwithstanding, a set of six selected model parameters could not be fully identified from existing observations at one station. After the introduction of prior knowledge of the ranges of meaningful parameter values, calibration of the over-parameterised model manifested itself primarily in the generation of posterior parameter covariances. Estimations of the covariance matrix based on (a) second order partial derivatives of a quadratic cost function at its optimum and (b) Monte Carlo simulations exploring the whole space of parameter values gave consistent results. Diagonalisation of the covariance matrix yielded two linear parameter combinations that were most effectively controlled by data from periods with and without lack of silica, respectively. The two parameter combinations were identified as the essential inputs that govern the successful simulation of intermittently decreasing chlorophyll a concentrations in summer. A satisfactory simulation of the pronounced chlorophyll a minimum in spring, by contrast, was found to be beyond the means of the simple model.

Description: We studied the impact of the last glacial (late Weichselian) sea level cycle on sediment architecture in theinner Kara Sea using high-resolution acoustic sub-bottom profiling. The acoustic lines were ground-truthedwith dated sediment cores. Furthermore we refined the location of the eastern LGM ice margin, by new subbottom profiles. New model results of post-Last Glacial Maximum (LGM) isostatic rebound for this area allowa well-constrained interpretation of acoustic units in terms of sequence stratigraphy. The lowstand (orregressive) system tract sediments are absent but are represented by an unconformity atop of Pleistocenesediments on the shelf and by a major incised dendritic paleo-river network. The subsequent transgressiveand highstand system tracts are best preserved in the incised channels and the recent estuaries while onlyminor sediment accumulation on the adjacent shelf areas is documented. The Kara Sea can be subdividedinto three areas: estuaries (A), the shelf (B) and (C) deeper lying areas that accumulated a total of 114 x1010 t of Holocene sediments.

Description: For most fish species raised in marine aquaculture, the use of live feeds cannot be replaced by formulated diets. Artemia nauplii and rotifers are still the most commonly used live feeds. A good alternative lies in the use of copepods which could lead to the cultivation of new fish species. Cold stored subitaneous eggs from the continuously cultured calanoid copepod Acartia tonsa were used to investigate the effect of storage upon the viability of the eggs, the development of the copepod community originating from the cold stored eggs. Finally a 3 days snapshot of the egg production of the first generation of females was followed. This was done in order to develop a database usable within copepod dependent hatcheries. The viability of cold stored A. tonsa eggs remained high (〉 70% hatching rate) for 11 months of storage. Generally, the period of storage was observed to decrease the viability (hatching rate) of the eggs and no hatching was observed after twenty months of cold storage. Hatched populations of copepods experienced increased mortality rate with longer storage of the eggs from which they originated. This mortality ranged from 0.035 to 0.13 d− 1 for non-stored (fresh) and 12 months stored eggs, respectively. However, all copepod communities originating from fresh to 12 months stored eggs reached adulthood. Additionally, the egg production from the stored generation was apparently normal and the viability of their eggs was not statistically different when compared to productions from non-stored communities. Contents of total fatty acids decreased during the storage period. Contents of free amino acids were not statistically different for eggs cold stored up to 12 months, but had decreased severely by 20 months. In conclusion, we consider it safe to store the eggs for up to one year at 2–3 °C during which the eggs retain their viability and biochemical composition. Cold storage of calanoid copepod eggs is relevant for aquaculture as inoculum for culturing live food.

Description: PU.1, IKAROS, E2A, EBF, and PAX5 comprise a transcriptional network that orchestrates B-cell lineage specification, commitment, and differentiation. Here we identify interferon regulatory factor 8 (IRF8) as another component of this complex, and show that it also modulates lineage choice by hematopoietic stem cells (HSCs). IRF8 binds directly to an IRF8/Ets consensus sequence located in promoter regions of Sfpi1 and Ebf1, which encode PU.1 and EBF, respectively, and is associated with transcriptional repression of Sfpi1 and transcriptional activation of Ebf1. Bone marrows of IRF8 knockout mice (IRF8−/−) had significantly reduced numbers of pre-pro-B cells and increased numbers of myeloid cells. Although HSCs of IRF8−/− mice failed to differentiate to B220+ B-lineage cells in vitro, the defect could be rescued by transfecting HSCs with wild-type but not with a signaling-deficient IRF8 mutant. In contrast, overexpression of IRF8 in HSC-differentiated progenitor cells resulted in growth inhibition and apoptosis. We also found that IRF8 was expressed at higher levels in pre-pro-B cells than more mature B cells in wild-type mice. Together, these results indicate that IRF8 modulates lineage choice by HSCs and is part of the transcriptional network governing B-cell lineage specification, commitment, and differentiation.

Description: Heme oxygenase-1 (HO-1) is an intracellular enzyme that degrades heme and inhibits immune responses and inflammation in vivo. In most cell types, HO-1 is inducible by inflammatory stimuli and oxidative stress. Here we demonstrate that human monocyte-derived immature dendritic cells (iDCs) and several but not all freshly isolated rat splenic DC subsets and rat bone marrow-derived iDCs, spontaneously express HO-1. HO-1 expression drastically decreases during human and rat DC maturation induced in vitro. In human tissues, iDCs also express HO-1, whereas mature DCs do not. Induction of HO-1 expression with cobalt protoporphyrin (CoPP) in human and rat DCs inhibits lipopolysaccharide (LPS)-induced phenotypic maturation and secretion of proinflammatory cytokines, resulting in the inhibition of alloreactive T-cell proliferation. CoPP-treated DCs, however, retain the ability to produce the anti-inflammatory cytokine interleukin 10 (IL-10). Reactive oxygen species induced by LPS in DCs were inhibited by induction of HO-1. In conclusion, we identify, for the first time, the capacity of HO-1 to block maturation of DCs and to inhibit proinflammatory and allogeneic immune responses while preserving IL-10 production. This novel immune function for HO-1 may be of interest for the inhibition of immune responses in autoimmune diseases, transplantation, and other conditions involving activation of the immune system. (Blood. 2005;106:1694-1702)

Description: In order to establish an efficient gd T cell-mediated immunotherapy for hematological malignancies, we tried to clarify whether γδ T cells could be expanded from blood cells of patients with myeloma, lymphoma and acute leukemia by culture with zoledronate and a low dose of IL-2 and whether the expanded patients’ γδ T cells could kill tumor cells including self tumor cells with sparing normal clone cells. In addition, we explored the methods to enhance the anti-tumor cytotoxicity of the expanded γδ T cells by activating them with type I IFN, monocyte-derived dendritic cells (mo-DCs), or ab T cells. Although γδ T cells could be expanded in patients with myeloma, lymphoma and leukemia as well as normal persons, the amplification rates of gd T cells before and after the culture were varied from patient to patient in the patients with hematological malignancies. γδ T cells generated in patients with myeloma and lymphoma showed a potent cytotoxic ability against myeloma/lymphoma cell lines (RPMI8226, Daudi) as shown in γδ T cells generated in normal persons. In addition, γδ T cells generated in a patient with myeloma and acute leukemia showed a cytotoxic ability against self myeloma or leukemia cells freshly prepared from bone marrow. However, the same γδ T cells were not cytotoxic to normal lymphocytes of the patients. Then the expanded γδ T cells were stimulated with type I IFN, mo-DCs, or αβ T cells and the activation (CD69 expression) and cytotoxicity against tumor cells were examined. By the stimulation with type I IFN, the expression of CD69 and Trail of γδ T cells was increased and the cytotoxic ability of γδ T cells was enhanced at dose-dependent manner of type I IFN. CD69 expression on γδ T cells was enhanced by co-culture with both immature and mature mo-DCs in a cell-number-dependent fashion. CD69 expression was enhanced after the addition of mo-DCs of either autologous or allogeneic origin. Activation of γδ T cells with mo-DCs enhanced anti-tumor cytotoxicity of γδ T cells against RPMI8226 and CML blastic crisis cell line (C2F8) in an effector-to-target ratio-dependent manner. Although CD69 expression of γδ T cells was enhanced by the co-culture with allogeneic ab T cells, autologous ab T cells couldn’t activate γδ T cells. However, autologous ab T cells stimulated with IL-2 or PHA could induce the activation of γδ T cells. The activation of γδ T cells with stimulated αβ T cells required cell-to-cell interaction. These findings suggested that αβ T cells stimulated by allogeneic γδ T cells could activate the same allogeneic γδ T cells. The present data demonstrated that γδ T cells, which could be expanded in vitro from blood cells of the patients with myeloma, lymphoma and leukemia by culture with zoledronate and IL-2, possess an enough cytotoxic ability against tumor cells including self tumor cells with sparing normal cells. These findings suggested that in vitro generated patients’ γδ T cells could be applied to γδ T cell-mediated immunotherapy for hematological malignancies. Besides, potent γδ T cells activated by type I IFN, mo-DCs or activated αβ T cells were considered to be applicable for γδ T cell-mediated immunotherapy.

Description: Vascular endothelial growth factor (VEGF), which induces angiogenesis and increases vascular permeability, is a major growth factor mediating tumor progression. In this study, we employed immunohistochemical-staining method to detect the expression of VEGF in lymph nodes taken from39 non-Hodgkin’s lymphomas patients and analyzed the relation of the expression levels to malignant aggressiveness, treatment response, histological grade, clinical stage and prognosis. The patients had been observed for at least 5 years or until death. 9 patients with benign lymphadenopathy were acted as control. The expression of VEGF was assessed according to the percentage of immunoreactive cells in a total of 1000 neoplastic cells (quantitative analysis). Immunoreactivity was graded positive, more than 10% of carcinoma cells stained and negative, no detectable staining or less than 10% of carcinoma cells stained. Furthermore, the qualitative intensity of staining for VEGF was assessed using a scale of 0–3+. The expression analysis of VEGF revealed that in 31 out of 39 (79.49%) specimens VEGF staining was positive. The VEGF staining was always cell membrane. Significant associations were found between the expression of VEGF and histological grade, Ann Arbor stage, prognosis (according to International Prognostic Index, IPI) and chemotherapy response. Among 8 cases of low grade, 7 had lower-level expression and 1 had higher-level expression, but among 31 cases of intermediate and high grade, 13 had lower-level expression and18 had higher-level expression (P=0.044

Description: We examined a large cohort (N=2,457) of chronic lymphocytic leukemia (CLL) patients evaluated by the CLL Research Consortium (CRC) and found 63 (2.6%) used IGHV3-21. Comparing the Ig heavy chain third complementarity determining region (HCDR3) of the IGHV3-21 cases: 25/63 cases (39.7%) had a conserved amino acid motif (motif 1: DANGMDV) in the otherwise highly variable Ig HCDR3, as described by Tobin et al. Blood 2003. All but one of these Ig heavy chains (IgH) were paired with a lambda light chain encoded by IGLV3-21. In addition, we found that 3/63 cases (4.8%) had a previously unrecognized conserved HCDR3 amino acid motif (motif 2: DPSFYSSSWTLFDY). In contrast, these IgH invariably were paired with kappa immunoglobulin light chains (IgL) encoded by IGKV3-20. Similarly to that noted for CLL cases that use IgH encoded by unmutated IGHV1-69 (Widhopf et al. Blood Epub First Edition 2007), the pairing of IgH encoded by IGHV3-21 with IgL appears governed by the HCDR3. The non-stochastic pairing of IgH with IgL argues strongly that antigen plays a role in selecting the Ig expressed in CLL. To examine for the antigen(s) recognized by the most common Ig encoded by IGHV3-21, we isolated IgH and IgL genes expressed by IGHV3-21/IGLV3-21 CLL cases and generated recombinant antibodies, which we examined for binding to antigen(s) present on microarray of self or environmental antigens. We found that Ig encoded by IGHV3-21/IGLV3-21 had apparent specific binding for protein L, a multi-domain cell-wall protein isolated from Peptostreptococcus magnus, a Gram-positive commensal bacteria that comprise a large portion of the human bacterial gut flora. Prior studies identified that protein L is a superantigen capable of binding human Ig kappa light chains encoded by IGKV genes of the I, III, and IV subgroups, but not human Ig lambda light chains. The specific binding of IGHV3-21/IGLV3-21 to protein L suggested that protein L might play a role in the development of CLL cells that express such Ig. To test this hypothesis, we examined the capacity of various recombinant antibodies to bind protein L by ELISA. We found that lambda IgL encoded by IGLV3-21 could bind to protein L with similar activity, independent of whether this lambda IgL paired with the native IgH, IgH encoded by IGHV3-21 lacking the DANGMDV HCDR3 motif, or even irrelevant IgH encoded by IGHV4-39 that are not found paired with IGLV3-21 in the Ig expressed in CLL. Moreover, Ig formed by pairing IgH encoded by IGHV3-21 that has the DANGMDV HCDR3 motif with an IgL encoded by an IGLV that was irrelevant to IGLV3-21 did not bind protein L. These results reveal a previously unrecognized capacity of human IgL encoded by IGLV3-21 to bind the protein L superantigen of Peptostreptococcus magnus, a bacteria commonly found in the human gastrointestinal tract. However, because the binding of IGLV3-21 does not depend upon the non-stochaistic pairing of IgH and IgL observed in CLL, we reason that the capacity of IGLV3-21 to bind protein L cannot account for the selected Ig repertoire expressed in CLL, suggesting that it actually does not play a role in CLL leukemogenesis. This finding suggests that caution should be exercised when defining an antigen that is found capable of binding the restricted Ig expressed in CLL as the driving factor responsible for leukemogenesis.

Description: Background: Heavy chain disease (HCD) is a rare lymphoproliferative disorder characterized by a monoclonal heavy chain (HC) unattached to a light chain (LC). IgGHCD or γHCD typically presents as a lymphoproliferative disorder with lymphadenopathy and hepatosplenomegaly. Myeloma has been described associated with γHCD but only with a second intact Ig paraprotein. This report describes a unique presentation of multiple myeloma with monoclonal free γ3HC and kappa free light chains. Case: A 34 year old gentleman presented with mild persistent neutropenia following two episodes of pneumonia, 18 months previously. He admitted to persistent night sweats but no other significant history. Baseline investigations revealed a mild anaemia, neutropenia and a large IgG paraprotein with no associated light chain. Bone marrow aspirate and trephine confirmed myeloma. The patient was treated with cyclophosphamide, thalidomide and dexamethasone and has had a very good partial remission. He is awaiting a sibling allogeneic peripheral blood stem cell transplant. Investigations and results: Serum Electrophoresis confirmed a large IgG paraprotein (23g/l) with no associated light chain in the serum and identified as γ3 subclass by radial immunodiffusion. Western blot showed the γ3HC was truncated with a large deletion. Markedly elevated free kappa (κ) LC (503.58 mg/l [3.30–19.4]) were found in the serum with gross skewing of the kappa/lambda ratio. Urine electrophoresis revealed separate γHC and κ LC paraproteins. Western blot of the fractionated urine protein demonstrated different sized κLC aggregates. Flow cytometry of the marrow aspirate revealed an unusual staining pattern; CD5,19,38,45+ve and CD20,22,23,34,56,138 –ve plasma cells. Cytoplasmic staining revealed 2 distinct populations of plasma cells, the first producing γ3HC and the second only free κLC. Cytogenetics and FISH analysis for 14q, p53 and c-myc abnormalities were normal. Discussion: This is the first description of a Biclonal Myeloma with separate plasma cell populations producing γ3HC and κLC paraproteins. The biclonality confirms the free HC occurs as a result of abnormal synthesis not cleavage. The clinical and immunological findings are clearly different to typical findings in both γ3HCD and Myeloma. HCD has an appalling prognosis and this case is likely to have been ‘smouldering’ for 18 months, evidenced by the 2 pneumonias and persistent night sweats. There is no lymphadenopathy or organomegaly associated with γ3HCD. The immunophenotype of the malignant plasma cells is unique. Other atypical features include frank proteinuria, with a HC in the urine, but normal renal function and no radiological or biochemical evidence of bone involvement. We propose that this unique biclonal myeloma has distinct immunological and clinical features.

Description: To realize the therapeutic potential of human embryonic stem cells (hESCs), it is necessary to regulate their differentiation in a uniform and reproducible manner. We have developed a method in which known numbers of hESCs in serum-free medium were aggregated by centrifugation to foster the formation of embryoid bodies (EBs) of uniform size (spin EBs). These spin EBs differentiated efficiently and synchronously, as evidenced by the sequential expression of molecular markers representing stem cells, primitive streak, and mesoderm. In the presence of hematopoietic growth factors, reproducible differentiation was achieved with blood cells formed in more than 90% of EBs. Using chimeric EBs generated from mixtures of green fluorescence protein–positive (GFP+) and GFP– hESCs in a clonogenic assay, hematopoietic precursor frequency was estimated to be approximately 1:500 input cells. This method of EB formation provides a generally applicable means for modulating and objectively monitoring the directed differentiation of hESCs.

Description: A distinct feature of multiple myeloma (MM) is the tight interaction between malignant plasma cells and their bone microenvironment, creating a niche suitable for MM growth. In particular, MM cells inhibit osteoblast (OB) differentiation and stimulate osteoclast (OC) function, resulting in imbalanced bone remodeling and osteolytic bone disease. Here we studied a novel cytokine, activin A, identified from a broad range of cytokines, in the development of MM bone disease. We next asked whether activin A inhibition could restore bone balance and suppress tumor growth. Activin, a member of the TNF-α superfamily, is a pleiotropic cytokine involved in bone remodeling. Here, we observed, that MM patients with multiple osteolytic lesions had a 4-fold increase in activin A expression levels in bone marrow plasma compared to MM patients with one or less osteolytic lesions and non-MM patients (average 123.6 ± 136 vs 26.4 ± 21.4 vs 30.6 ± 25.1 pg/ml respectively, p

Description: The past decade has shown a marked increase in the use of high-throughput assays in clinical research into human cancer, including acute myeloid leukemia (AML). In particular, genome-wide gene expression profiling (GEP) using DNA microarrays has been extensively used for improved understanding of the diagnosis, prognosis, and pathobiology of this heterogeneous disease. This review discusses the progress that has been made, places the technologic limitations in perspective, and highlights promising future avenues

Description: As previously reported (Colombat, Blood2001;97:101), rituximab (4 weekly doses of 375mg/m²) can lead to high response rates (RR) and prolonged remissions with minimal toxicity as 1st line therapy for low tumor burden FL. We report the final analysis of a trial evaluating long term efficacy and safety of rituximab in untreated low tumor burden FL (GELF criteria). 49 patients (pts) were included in the initial trial (median age 52 yrs), 2 refused consent for the extended F/Up period, and 1 pt died at M12. Molecular bcl2-JH rearrangement was assessed throughout the study. The median F/up was 83.8 mths. Overall best RR, complete/unconfirmed RR and partial RR at D78 were 74%, 50% and 24% respectively. Median PFS was 23.5 mths for the study population. Median duration of response (34 responders at D78, i.e 6 weeks after the last rituximab dose) was 28.6 mths, but response was still maintained without any further treatment in 11 pts after 5 years (24%) and in 7 pts after 7 years (15%). 31/46 pts were bcl2 positive in blood and/or marrow samples before rituximab: 11 (35%) became negative at D50, and 20 remained positive (65%). Median PFS was 37 mths for bcl2-negative pts at D50, and 12 mths for patients remaining positive (p=0.018 Log-rank). Of the 7 pts with sustained response after 7 years, 5 were bcl2 positive at D0, 2/5 became negative at D50, and 5/5 were still negative at M84. At year 7, 4/46 pts have died (1 from myelodysplasia, 3 from NHL), 35/42 have progressed, and 7 have never progressed without any other treatment than the initial rituximab therapy. Time to progression was significantly longer in the bcl2-negative population at D50 (p= 0.018, Log-rank). Duration of response was not correlated with bcl2 status at D50, but was associated with ‘Best response CR/Cru’ (p=0.007 Log-rank). Long-term tolerance was good, with only 13 SAE observed in 13 pts during the additional 4 years of F/Up (4 surgeries for non NHL-related pathologies, 1 node biopsy, 1 sleep apnea syndrome, 1 ischemic cardiopathy, 2 deaths from NHL, 1 depression, 1 pneumonia, 1 erysipela, 1 bronchitis). This long-term update confirms that a single 4-dose rituximab treatment yields durable benefits without the toxicity of chemotherapy for pts with low burden FL : Median PFS of 23.5 mths for the cohort, 28.6 mths for responders and 37 mths for pts turning bcl2-negative at D50, 15% of pts have maintained their response after 7 years, (2bis) the quality (CR/Cru) of the initial response was associated with a longer response duration high overall survival is observed with 4 deaths/46 pts (8.6%).

Description: Background: Recent advances in the therapy of multiple myeloma (MM) have greatly increased the treatment options for this uniformly fatal plasma cell malignancy. It is not clear if introduction of novel therapies and the increased use of high dose therapy (HDT) in the past decade have translated into better outcome for patients (pts) with MM. Methods: We examined the outcome of two cohorts of pts seen at our institution. The first cohort consisted of 387 pts who relapsed after HDT and was examined for potential improvement in survival following relapse after HDT. These pts were divided into two groups; those who relapsed before or after December 31, 2000. The second cohort consisted of 2981 patients with newly diagnosed MM seen between January 1971 and December 2006 and was used to examine the trends in overall survival (OS). Results: Among those relapsing after HDT, there were 245 males (63%); median (range) age at HDT was 57 years (32.8–75.4) and the median time to HDT was 8.1 months (1–90 months) from diagnosis. The median time to relapse was 13.2 months (1.1 months-10.3 years) from HDT. In this cohort, a clear improvement in OS from time of relapse was seen over the past decade, with those relapsing after 2000 having a median OS of 23.9 months (95% CI; 19.8, 27.6) compared to 11.8 months (95% CI; 8.7, 14.9) for the rest (P 〈 0.001) (Figure 1). In a multivariate analysis, the effect of the date of relapse on survival was independent of other prognostic factors such as relapse 5.5 mg/dL. Pts who were treated with one or more of the newer drugs (thalidomide, lenalidomide, bortezomib) had longer survival from relapse (30.9 months (95% CI; 23.6, 38.2) compared to 14.8 months (95% CI; 11.3, 18.4); P 〈 0.001) for others. Among the newly diagnosed MM cohort, the median age at diagnosis was 66 years (20.2 – 97 years), and 1,770 (59.4%) were males. The median follow up for the entire group was 27.4 months (0–29.4 years); and at the time of analysis 558 patients (18.7%) were alive with a median follow up of 32.7 months (0–29.4 years). Pts diagnosed in the last decade had an improved OS (44.8 months) compared to those diagnosed before this period (29.9 months; P 〈 0.001) (Figure 2). The improvement in survival seen in the last decade among newly diagnosed patients was predominantly among those younger than 65 years (60.3 mos vs. 33.3 mos improvement in median survival); compared to those over 65 at diagnosis (26.5 mos vs. 32 mos). Conclusion: In this study, for the first time, we demonstrate definite proof for improved outcome in patients with myeloma, both in the relapsed setting as well as at diagnosis, a change that is likely to continue with increased use of these drugs. Figure Figure Figure Figure

Description: INTRODUCTION: Proteasome inhibitors (PI) and histone deacetylase inhibitors (HDACi) have demonstrated synergistic pre-clinical activity in multiple myeloma (MM). The goals of this study were to evaluate this combination regimen’s clinical activity and adverse events, including thrombocytopenia (TCP) since both drug classes may cause transient TCP. We performed an open label, single-centre, single-arm, phase I/II, dose-escalation trial of bortezomib, dexamethasone and romidepsin (depsipeptide) in relapsed or refractory MM. This is the first clinical trial to combine these 3 agents. METHODS. All patients (pts) received bortezomib (1.3mg/m2 d1, 4, 8, 11) with dexamethasone (20mg d1, 2, 4, 5, 8, 9, 11, 12). Romidepsin commenced at 8 mg/m2 IV d1, 8, and 15 every 28 days with a planned accelerated intra-patient dose escalation to 10, 12 and 14 mg/m2 (n=10). After CR + 2 cycles or a maximum of 8 cycles, pts with SD or better commenced maintenance (Mx) therapy, romidepsin at the MTD on days 1 and 8 of a 28 day cycle until PD. An additional 15 pts were treated at the MTD in a phase II expansion. Response was assessed after every 2 cycles according to IMWG criteria (with minimal Response (MR) defined as ≥25% but

Description: Endothelial cells secrete prothrombotic ultralarge von Willebrand factor (VWF) multimers, and the metalloprotease ADAMTS13 cleaves them into smaller, less dangerous multimers. This reaction is stimulated by tensile force applied to the VWF substrate, which may occur on cell surfaces or in the circulating blood. The cleavage of soluble VWF by ADAMTS13 was accelerated dramatically by a combination of platelets and fluid shear stress applied in a cone-plate viscometer. Platelet-dependent cleavage of VWF was blocked by an anti-GPIbα monoclonal antibody or by a recombinant soluble fragment of GPIbα that prevents platelet-VWF binding. Multimeric gel analysis showed that shear and platelet-dependent cleavage consumed large VWF multimers. Therefore, ADAMTS13 preferentially acts on platelet-VWF complexes under fluid shear stress. This reaction is likely to account for a majority of VWF proteolysis after secretion and to determine the steady-state size distribution of circulating VWF multimers in vivo.

Description: Abstract 1689 Poster Board I-715 Introduction The use of the proteasome inhibitor bortezomib has demonstrated activity in multiple myeloma and lymphomas. The HDAC inhibitor romidepsin is being evaluated in CTCL and PTCL, though its activity in B-cell lymphomas is less clear. We hypothesized that the combination of bortezomib and romidepsin would result in synergistic apoptosis in different B-cell NHL cell lines based upon the observed activity of this combination in more mature B-cell malignancies such as myeloma. Experimental Design Daudi, HT, Ramos and SUDHL-4 cell lines were exposed to different concentrations of bortezomib and romidepsin, separately, concurrently, and sequentially. Cell viability was assessed using MTT-assay, induced apoptosis was evaluated using Annexin V and PI staining from 24-48 hours. Apoptosis was also evaluated using western blot analysis of caspases and PARP cleavage. LC3 and HDAC6 level expressions were performed to determine if the effect of the combination was a result of the aggresome or autophagy pathway. Cell cycle studies were also performed to study if there were any changes after treating cells with the combination. Results The combination of bortezomib and romidepsin resulted in synergistic B-cell apoptosis as measured by MTT-assay with combination indices of 〈 0.5. This was associated with increased caspases and PARP cleavage as early as 24 hours after exposure. Order of addition experiments demonstrated definite sequence specificity. When romidepsin was added first, and 6 hours later followed by bortezomib, apoptosis was enhanced, compared to both agents being given concurrently or when bortezomib was administered first. Cell cycle analysis studies demonstrated that pretreatment of cells with romidepsin for 6 hours followed by the addition of bortezomib arrested the cells in G2M phase. HDAC6 expression was significantly reduced following combination therapy, and LC3-I was cleaved to LC3-II in treated cells suggesting that the combination affected aggresome formation and autophagy. Conclusion The combination of romidepsin and bortezomib at low nanomolar concentrations suggests that this may be an important clinical combination to test in patients with relapsed or refractory B-cell malignancies. Sequence of administration data is currently being tested to determine if the effect is a result of autophagy inhibition as is seen in myeloma cell lines. Additional mechanistic studies will be presented with the goals of identifying predictors of response that can then be validated in prospective clinical trials. Disclosures Lechowicz: Gloucester: Consultancy. Kaufman:Millennium: Consultancy; Genzyme: Consultancy; Celgene: Consultancy; Merck: Research Funding; Celgene: Research Funding. Lonial:Gloucester: Research Funding; Novartis: Consultancy; BMS: Consultancy; Millennium: Consultancy, Research Funding; Celgene: Consultancy. Flowers:Millennium: Research Funding.

Description: Abstract 3701 Poster Board III-637 Background Romidepsin is an anti-neoplastic agent that has been identified as a novel pan-HDAC inhibitor with single-agent activity in T-cell lymphoma. In a combined analysis of 167 patients (pts) with cutaneous T-cell lymphoma (CTCL) from 2 clinical studies (GPI and NCI studies), the overall response rate was 35%, including 10 pts with a complete clinical response (CCR). Median duration of response was 13.8 months and 42% of pts with advanced disease (stage ≥IIB) responded [Demierre et al. J Clin Oncol 27:15s, 2009 (suppl; abstr 8546)]. The most common hematologic abnormalities in these pts included anemia (41%), thrombocytopenia (34%), neutropenia (27%), and lymphopenia (26%). Most hematologic toxicities were Grade 1 or 2, although 'Grade 3 events were observed. These events were reversible and a small portion of the patients discontinued the study drug because of these events (2%). This report details an analysis of platelet counts in pts receiving romidepsin and an investigation into the mechanism of thrombocytopenia in nonclinical studies. Methods Pts with CTCL who received ≥1 prior systemic therapy failure and had an ECOG PS of 0-2 were enrolled in 2 single-arm, open-label, multicenter and international clinical studies. Treatment with QTc prolonging therapies or CYP34A inhibitors was prohibited and pts with significant cardiovascular abnormalities were excluded. Romidepsin at 14 mg/m2 was administered as a 4-hr IV infusion on days 1, 8, and 15 of a 28 day cycle. Nonclinical studies were conducted in mice to investigate the mechanism of romidepsin effects on platelets. Romidepsin was administered to female BALB/c mice at doses of 1 or 4 mg/kg by tail-vein injection on days 1, 5 and 9. Blood samples were collected every 2 days from alternating groups of mice to minimize effects of bleeding on platelet counts. Results In clinical studies, there is a mean decrease in platelet counts during the treatment period of each cycle, and a return to baseline levels or above between cycles observed in both clinical studies as described in the table below. No clinically meaningful change has been observed in the central tendency over 4 cycles of treatment in both studies. In the mouse studies, dose-dependent effects were seen on both WBC and platelet counts. Day 2 WBC counts dropped to 45% and 10% of normal at the 1 and 4 mg/kg doses, respectively. WBC counts remained low until after the dosing period in the 1 mg/kg romidepsin group, but recovered more quickly in the 4 mg/kg group. Day 2 platelet counts were 70% of normal at the 1 mg/kg dose and remained near this level until day 10, followed by recovery to normal at day 15. At the 4 mg/kg dose, profound thrombycytopenia was induced, with platelet counts only 20% of normal on days 4-6. Platelet counts slowly recovered to 70% of normal by day 15. Plasma thrombopoietin levels were normal throughout the experiment for the 1 mg/kg group, and showed a large increase to 275% of normal on day 6 in the 4 mg/kg group, which is the expected response to thrombocytopenia as a signal to increase platelet production and indicates that platelet reduction is not attributable to defective TPO production. Bone marrow megakaryocyte populations are being examined to determine the effects of romidepsin on these platelet-producing cells. Conclusions Following romidepsin administration, a saw tooth pattern is observed in the reduction and recovery of platelets. Recovery of platelets appears to occur more rapidly in humans than in mice; however, the effects are reversible after dosing in clinical studies and in murine models. In the clinical data the recovery pattern suggests that the transient effects are direct and are not effects on bone marrow. Disclosures: Whittaker: Gloucester Pharmaceuticals: Research Funding. Prince:Gloucester Pharmaceuticals: Consultancy. Demierre:Gloucester Pharmaceuticals: Consultancy, Honoraria. Lonial:Gloucester Pharmaceuticals: Honoraria. Kim:Gloucester Pharmaceuticals: Consultancy, Honoraria. Nichols:Gloucester Pharmaceuticals: Employment, Equity Ownership. Nix:Gloucester Pharmaceuticals: Employment.

Description: Precursor T-cell acute lymphoblastic leukemia (T-ALL) in children represents a clinical challenge, because relapses are usually fatal. It is thus necessary to identify high-risk patients as early as possible to effectively individualize treatment. We aimed to define novel molecular risk markers in T-ALL and performed array-based comparative genomic hybridization (array-CGH) and expression analyses in 73 patients. We show that DNA copy-number changes are common in T-ALL and affect 70 of 73 (96%) patients. Notably, genomic imbalances predicted to down-regulate the TGF-β or up-regulate the PI3K-AKT pathways are identified in 25 of 73 (34%) and 21 of 73 (29%) patients, suggesting that these pathways play key roles in T-ALL leukemogenesis. Furthermore, we identified a deletion at 6q15-16.1 in 9 of 73 (12%) of the patients, which predicts poor early treatment response. This deletion includes the CASP8AP2 gene, whose expression is shown to be down-regulated. The interaction of CASP8AP2 with CASP8 plays a crucial role in apoptotic regulation, suggesting a functional link between the clinical effect of the deletion and the molecular mode of action. The data presented here implicate the TGF-β and PI3K-AKT pathways in T-ALL leukemogenesis and identify a subgroup of patients with CASP8AP2 deletions and poor early treatment response.

Description: Absence of shear stress due to disturbed blood flow at arterial bifurcations and curvatures leads to endothelial dysfunction and proinflammatory gene expression, ultimately resulting in atherogenesis. KLF2 has recently been implicated as a transcription factor involved in mediating the anti-inflammatory effects of flow. We investigated the effect of shear on basal and TNF-α–induced genomewide expression profiles of human umbilical vein endothelial cells (HUVECs). Cluster analysis confirmed that shear stress induces expression of protective genes including KLF2, eNOS, and thrombomodulin, whereas basal expression of TNF-α–responsive genes was moderately decreased. Promoter analysis of these genes showed enrichment of binding sites for ATF transcription factors, whereas TNF-α–induced gene expression was mostly NF-κB dependent. Furthermore, human endothelial cells overlying atherosclerotic plaques had increased amounts of phosphorylated nuclear ATF2 compared with endothelium at unaffected sites. In HUVECs, a dramatic reduction of nuclear binding activity of ATF2 was observed under shear and appeared to be KLF2 dependent. Reduction of ATF2 with siRNA potently suppressed basal proinflammatory gene expression under no-flow conditions. In conclusion, we demonstrate that shear stress and KLF2 inhibit nuclear activity of ATF2, providing a potential mechanism by which endothelial cells exposed to laminar flow are protected from basal proinflammatory, atherogenic gene expression.

Description: The cAMP-responsive element binding protein (CREB) is a 43-kDa nuclear transcription factor that regulates cell growth, memory, and glucose homeostasis. We showed previously that CREB is amplified in myeloid leukemia blasts and expressed at higher levels in leukemia stem cells from patients with myeloid leukemia. CREB transgenic mice develop myeloproliferative disease after 1 year, but not leukemia, suggesting that CREB contributes to but is not sufficient for leukemogenesis. Here, we show that CREB is most highly expressed in lineage negative hematopoietic stem cells (HSCs). To understand the role of CREB in hematopoietic progenitors and leukemia cells, we examined the effects of RNA interference (RNAi) to knock down CREB expression in vitro and in vivo. Transduction of primary HSCs or myeloid leukemia cells with lentiviral CREB shRNAs resulted in decreased proliferation of stem cells, cell- cycle abnormalities, and inhibition of CREB transcription. Mice that received transplants of bone marrow transduced with CREB shRNA had decreased committed progenitors compared with control mice. Mice injected with Ba/F3 cells expressing either Bcr-Abl wild-type or T315I mutation with CREB shRNA had delayed leukemic infiltration by bioluminescence imaging and prolonged median survival. Our results suggest that CREB is critical for normal myelopoiesis and leukemia cell proliferation.

Description: Venous thromboembolism (VTE) is increasingly diagnosed among individuals with hematologic malignancies. However, the risk of VTE among patients undergoing hematopoietic stem cell transplantation (HSCT) is unclear. We examined the incidence and risk factors for VTE and bleeding among 1514 patients undergoing in-patient HSCT. No protocolized VTE prophylaxis was used. By HSCT day 180, 75 symptomatic VTE occurred in 70 patients (4.6%; 95% confidence interval [CI], 3.6%-5.8%). Fifty-five (3.6%) were catheter-associated, 11 (0.7%) were non–catheter-associated deep venous thromboses, and 9 (0.6%) were pulmonary emboli. Thirty-four percent of VTE occurred at a platelet count less than 50 ×109/L; 13% occurred at a platelet count less than 20 ×109/L. In multivariate analysis, VTE was associated with prior VTE (odds ratio [OR], 2.9; 95% CI, 1.3-6.6) and with graft-versus-host disease (GVHD; OR, 2.4; 95% CI, 1.4-4.0). Clinically significant bleeding occurred in 230 patients (15.2%; 95% CI, 13.4%-17.1%); 55 patients (3.6%; 95% CI, 2.7%-4.7%) had fatal bleeding. Bleeding was associated with anticoagulation (OR, 3.1; 95% CI, 1.8-5.5), GVHD (OR, 2.4; 95% CI, 1.8-3.3), and veno-occlusive disease (OR, 2.2; 95% CI, 1.4-3.6). In HSCT patients, VTE is primarily catheter-related and 3-fold less common than clinically significant bleeding. These findings warrant consideration when selecting VTE prophylaxis in HSCT patients.

Description: Tumor cell–associated tissue factor (TF) is a powerful determinant of metastatic potential. TF may increase metastasis by supporting thrombin-mediated proteolysis, through intracellular signaling events mediated by the TF cytoplasmic domain, through TF/fVIIa/fXa–mediated activation of protease-activated receptors, or through a combination of these processes. To better define the relationship between tumor cell-associated TF and circulating hemostatic factors in malignancy, we generated a set of C57Bl/6-derived tumor lines genetically lacking TF, expressing wild-type murine TF, or expressing a mutant TF lacking the cytoplasmic domain. Comparison of the metastatic potential of these cells in immunocompetent mice with genetic deficits in prothrombin, platelet function, or fibrinogen revealed that TF supports metastasis through mechanisms independent of the cytoplasmic domain, but dependent on each of these distal hemostatic factors. TF was neither required for primary tumor growth nor necessary for initial localization of embolized tumor cells within the lungs. Rather, tumor cell fate studies indicated TF supports metastasis by increasing the survival of micrometastases. One mechanism linking TF to metastasis is through a fibrin(ogen)-dependent and platelet-dependent restriction in natural killer cell–mediated clearance of micrometastases. However, TF also supported the early success of micrometastases through an additional mechanism independent of natural killer cells, but coupled to circulating prothrombin.

Description: Recent studies have demonstrated that in peripheral lymphoid tissues of normal mice and healthy humans, 1% to 5% of αβ T-cell receptor–positive (TCR+) T cells are CD4−CD8− (double-negative [DN]) T cells, capable of down-regulating immune responses. However, the origin and developmental pathway of DN T cells is still not clear. In this study, by monitoring CD4 expression during T-cell proliferation and differentiation, we identified a new differentiation pathway for the conversion of CD4+ T cells to DN regulatory T cells. We showed that the converted DN T cells retained a stable phenotype after restimulation and that furthermore, the disappearance of cell-surface CD4 molecules on converted DN T cells was a result of CD4 gene silencing. The converted DN T cells were resistant to activation-induced cell death (AICD) and expressed a unique set of cell-surface markers and gene profiles. These cells were highly potent in suppressing alloimmune responses both in vitro and in vivo in an antigen-specific manner. Perforin was highly expressed by the converted DN regulatory T cells and played a role in DN T-cell–mediated suppression. Our findings thus identify a new differentiation pathway for DN regulatory T cells and uncover a new intrinsic homeostatic mechanism that regulates the magnitude of immune responses. This pathway provides a novel, cell-based, therapeutic approach for preventing allograft rejection.

Description: When adopting basic principles learned in mice to clinical application in humans, it is often difficult to distinguish whether a “translation” fails because of an invalid target in the human disease or because the therapeutic agents are not optimal for the human target. It is, therefore, desirable to develop preclinical models to optimize therapies for human targets using in vivo settings. Although anti–mouse CTLA-4 antibodies are known to enhance immune responses in vivo, their effect on T-cell activation in vitro ranges from enhancement to inhibition. Here we use the hu-PBL-SCID mouse model of Epstein-Barr virus (EBV)–associated lymphoma development to screen a panel of anti–human CTLA-4 monoclonal antibodies (mAbs) for their effect on human lymphocytes in an in vivo “humanized” environment. We report significant heterogeneity of anti–human CTLA-4 mAbs in enhancing the expansion of human T cells in mice, and this heterogeneity cannot be attributed to immunoglobulin isotypes or affinity for CTLA-4. These data validate the development of additional screening tools, such as the one described, to further characterize functional activity of antihuman antibodies before proceeding with clinical translation to human studies.

Description: Abstract 1955 Poster Board I-978 The detection of chromosome abnormalities in mature B-cell neoplasms by conventional cytogenetics remains difficult, mainly due to the low proliferative rate of mature lymphoid cells. The current FISH panel for chronic lymphocytic leukemia (CLL) is designed to detect some of the more common abnormalities of prognostic significance in CLL [i.e., del(6q), del(11q), +12, del(13q), del(17p)]. This CLL FISH panel has improved the detection rate of these markers by making it possible to obtain cytogenetic information from interphase cells; however, as it is limited to only these 5 markers, it cannot detect all abnormalities associated with CLL. More importantly, the impact of other chromosome abnormalities on prognosis and disease progression, with and without the presence of these 5 prognostic markers, is not known. CpG-oligodeoxynucleotides (ODNs) such as DSP30 activate cells of the immune system in a sequence-dependent manner and promote proliferation of CLL cells in vitro [Decker et al. Blood 2000;95:999-1006]. They also upregulate costimulatory molecules and potential target antigens during immunotherapy. The use of DSP30 in combination with interleukin 2 (IL2) has proven effective in increasing the detection of chromosome abnormalities in CLL [Dicker et al. Blood 2006;108:3152-60] and other mature B-cell lymphoid malignancies by conventional cytogenetics [Struski et al. Leukemia 2009;23:617-9], when compared to the well-established B-cell mitogens. In our extensive clinical experience of incorporating DSP30/IL2 into our culture media, this cocktail has significantly increased the detection of chromosome abnormalities in CLL by conventional cytogenetics, from 55% to greater than 80%. We thus decided to investigate if various other lymphoid malignancies would respond to the mitogen activity of DSP30/IL2 as well as or better than CLL. Specifically, we evaluated 812 cases of mature B-cell lymphoid malignancies that were abnormal by flow cytometry, morphology, or cytogenetic analysis. All samples (bone marrow or blood) were cultured for approximately 72 hours using the DSP30/IL2 mitogen cocktail. Of these 812 cases, 746 (91%) provided sufficient mitotic index and quality for a complete cytogenetic analysis and interpretation. Of the CLL cases (n=509), 79 were initially interpreted as normal by conventional cytogenetic analysis, but were later interpreted as abnormal by FISH for deletion 13q only. In view of the known cryptic nature of this deletion in CLL, these cases were not included in the study, leaving a total of 430 CLL cases, and thus bringing the total number of cytogenetically successful study cases to 667. In addition to the 430 CLL cases, there were 14 variant CLLs; 36 diffuse large B-cell lymphomas (DLBCLs); 35 follicular lymphomas; 34 non-Hodgkin lymphomas (not further specified); 29 marginal zone B-cell lymphomas of splenic type (sMZBCL); 27 mantle cell lymphomas (MCLs), of which 8 were blastoid; 16 MZBCL of MALT type; 13 hairy cell leukemias (HCLs); 12 lymphoproliferative disorders (not further specified); 10 lymphoplasmacytic lymphomas (LPLs); 6 Burkitt lymphomas; 3 Hodgkin lymphomas; and 2 B-cell prolymphocytic leukemias (PLLs). Of particular interest is the fact that we detected clonal abnormalities in 100% of HCLs, blastoid MCLs, variant CLLs, and B-cell PLL, as well as in 97% of sMZBCLs, 89% of DLBCLs, and 80% of LPLs This is of great importance since HCLs and LPLs are rarely abnormal by conventional cytogenetics using the more traditional combinations of mitogens making it difficult to identify markers of prognostic significance. In conclusion, our findings demonstrate that the DSP30/IL2 cocktail induces proliferation of various B-cell mature lymphoid disorders and that its mitogenic action is not limited to CLL. We are continuing to develop our understanding of the considerable response of specific lymphoid malignancies to the DSP30/IL2 cocktail by correlating additional clinical data, and hope that the end result will open new avenues in regards to prognostic outcome and therapeutic approaches. Disclosures: No relevant conflicts of interest to declare.

Description: Higher levels of procoagulant factors and factor XII deficiency may be risk factors for first venous thromboembolism (VTE). We studied associations of coagulation factors IX through XIII with risk of future VTE in 2 general population samples. Using a nested case-control study combining the 21 860 participants of the Atherosclerosis Risk in Communities study and the Cardiovascular Health Study, we determined antigenic levels of these coagulation factors in primarily pre-event blood samples from 462 participants who subsequently developed VTE and 1047 participants who remained free of VTE. Only elevated levels of factors IX and XI were associated with increased risk of VTE after adjustment for age, sex, race, and study. For factor IX, the odds ratio (OR) was 1.4 (95% confidence interval [CI], 1.0-2.0) comparing the top to bottom quintile. The OR for factor XI was higher: 2.0 (95% CI, 1.4-2.9). With further adjustment for body mass index and diabetes, only elevated factor XI remained associated with VTE risk: OR 1.8 (95% CI, 1.3-2.7). Associations were similar by study and whether the thrombosis was idiopathic or secondary. Factor XII deficiency was not related to VTE risk. Among these procoagulant factors, only elevated factor XI was a risk factor for VTE.

Description: The concept of endothelial progenitor cells (EPCs) has attracted considerable interest in cardiovascular research, but despite a decade of research there are still no specific markers for EPCs and results from clinical trials remain controversial. Using liquid chromatography–tandem mass spectrometry, we analyzed the protein composition of microparticles (MPs) originating from the cell surface of EPC cultures. Our data revealed that the conventional methods for isolating mononuclear cells lead to a contamination with platelet proteins. Notably, platelets readily disintegrate into platelet MPs. These platelet MPs are taken up by the mononuclear cell population, which acquires “endothelial” characteristics (CD31, von Willebrand factor [VWF], lectin-binding), and angiogenic properties. In a large population-based study (n = 526), platelets emerged as a positive predictor for the number of colony-forming units and early outgrowth EPCs. Our study provides the first evidence that the cell type consistent with current definitions of an EPC phenotype may arise from an uptake of platelet MPs by mononuclear cells resulting in a gross misinterpretation of their cellular progeny. These findings demonstrate the advantage of using an unbiased proteomic approach to assess cellular phenotypes and advise caution in attributing the benefits in clinical trials using unselected bone marrow mononuclear cells (BMCs) to stem cell-mediated repair.

Description: The metalloprotease ADAMTS13 (a disintegrin and metalloprotease with thrombospondin motif) converts the hyperreactive unusually large (UL) forms of von Willebrand factor (VWF) that are newly released from endothelial cells into less active plasma forms by cleaving a peptide bond in the VWF A2 domain. Familial or acquired deficiency of this metalloprotease is associated with thrombotic thrombocytopenic purpura (TTP). ADAMTS13 belongs to the ADAMTS metalloprotease family, but, unlike other members, it also contains 2 C-terminal CUB domains (complement component Clr/Cls, Uegf, and bone morphogenic protein 1). Mutations in the CUB region have been found in congenital TTP, but deletion of the region did not impair enzyme activity in conventional in vitro assays. We investigated the functions of the CUB domain in ADAMTS13 activity under flow conditions. We found that recombinant CUB-1 and CUB-1+2 polypeptides and synthetic peptides derived from CUB-1 partially blocked the cleavage of ULVWF by ADAMTS13 on the surface of endothelial cells under flow. The polypeptide bound immobilized and soluble forms of ULVWF, and blocked the adhesion of ADAMTS13-coated beads to immobilized ULVWF under flow. These results suggest that the CUB-1 domain may serve as the docking site for ADAMTS13 to bind ULVWF under flow, a critical step to initiate ULVWF proteolysis.

Description: Severe ADAMTS13 deficiency in thrombotic thrombocytopenic purpura (TTP) is either constitutional and caused by ADAMTS13 mutations, or acquired and most often due to ADAMTS13 inhibitory autoantibodies. In strongly hemolytic serum of a pediatric patient, diagnosed with TTP postmortem, ADAMTS13 activity was less than 3%. Both parents had an ADAMTS13 activity of approximately 50%. Sequencing of the ADAMTS13 gene revealed an intronic 687-2A〉G substitution affecting exon 7, homozygous in the propositus and heterozygous in both parents, confirming constitutional ADAMTS13 deficiency. ADAMTS13 activity of normal plasma was inhibited by incubation with the propositus' serum, suggesting alloantibody formation to ADAMTS13. However, immunoglobulin purified from serum had no ADAMTS13 inhibitory effect, whereas the immunoglobulin-depleted hemolytic serum inhibited ADAMTS13 activity of normal plasma, suggesting an inhibitory effect of hemolysis products. Incubation of hemoglobin, recombinant and from lysed erythrocytes, with normal plasma revealed an ADAMTS13 inhibitory effect at hemoglobin concentrations of 2 g/L or higher.

Description: Donor cell expression of C3 enhances the alloimmune response and is associated with the fate of transplantation. To clarify the mechanism for enhancement of the immune response, we have explored the role of C3a receptor (C3aR)–ligand interaction on murine bone marrow dendritic cells (DCs). We show that DCs either lacked receptor for C3a (a C3 cleavage product) or were treated with C3aR antagonist, elicited defective T-cell priming against alloantigen expressed on the DCs. This was associated with reduced surface expression of major histocompatibility complex (MHC) and costimulatory molecules on the DCs, and with defective priming in skin allograft rejection. In addition, DCs lacking factor B were unable to generate potent T-cell responses against donor antigen, whereas lack of C4 had no detectable effect, suggesting a role for the alternative pathway contributing to allostimulation. Furthermore, therapeutic complement regulator can down-regulate DC allostimulatory function. These findings suggest that the capacity of DCs for allostimulation depends on their ability to express, activate, and detect relevant complement components leading to C3aR signaling. This mechanism, in addition to underpinning the cell-autonomous action of donor C3 on allostimulation, has implications for a wider range of immune responses in self-restricted T-cell priming.

Description: The role of the intrinsic coagulation system on the risk of myocardial infarction is unclear. In the Study of Myocardial Infarctions Leiden (SMILE) that included 560 men younger than age 70 with a first myocardial infarction and 646 control subjects, we investigated the risk of myocardial infarction for levels of factor XI (factor XIc) and factor XII (factor XIIc). Furthermore, the risks for factor VIII activity (factor VIIIc) and factor IX activity (factor IXc) were assessed. Factor XIc was 113.0% in patients compared with 109.8% in control subjects (difference, 3.2%; 95% CI, 1.1%-5.4%). The risk of myocardial infarction adjusted for age for men in the highest quintile compared with those in the lowest quintile was 1.8-fold increased (ORadj, 1.8; 95% CI, 1.2-2.7). In contrast, factor XIIc among patients with myocardial infarction was lower than in control subjects, respectively, 93.0% and 98.6% (difference, 5.6%; 95% CI, 3.3%-7.9%). The odds ratio of myocardial infarction for men in the highest quintile versus those in the lowest quintile was 0.4 (ORadj, 0.4; 95% CI, 0.2-0.5). The highest risk was found among men with both high factor XIc and low factor XIIc (analyses in tertiles: ORadj, 6.4; 95% CI, 2.2-18.0). Factor VIIIc increased the risk of myocardial infarction although not dose dependently. Factor IXc increased the risk; odds ratio of myocardial infarction for men in the highest quintile versus those in the lowest quintile was 3.2 (ORadj, 3.2; 95% CI, 2.0-5.1). Thus, factors XIc and XIIc have opposite and synergistic effects on the risk of myocardial infarction in men; factor VIIIc and factor IXc increase the risk.

Description: Background: A variety of ophthalmologic findings have been reported in patients with anemia. Aim: To determine the effect of beta-thalassemia minor on the optic nerve head topographic analysis. Methods: A total of 39 beta-thalassemia minor patients were divided into 2 groups. Patients with iron, folic acid, or vitamin B12 deficiency were ruled out. Group 1 comprised 20 patients with anemia, and group 2 comprised 19 patients without anemia. One eye of each patient was included into the study. All subjects underwent complete ocular examination. Optic nerve head topographic analysis was performed by using a confocal scanning laser ophthalmoscope type Heidelberg retina tomograph (HRT). The following stereometric parameters were evaluated: disc area, area and volume of cup, area and volume of neuroretinal rim, measure of cup shape, and mean retinal nerve fiber layer thickness. Results: The mean age of group 1 and 2 were 26.8±7.6 and 25.6±4.5 years, respectively (P=0.91). Their mean disc areas were 2.01±0.3 mm2 and 2.53±0.6 mm2, respectively (P =0.009). The differences between groups for area and volume of cup, area and volume of neuroretinal rim, cup shape measure, and mean retinal nerve fiber layer thickness were insignificant (p〉0.05). There was no significant difference between mean intraocular pressure of both groups (p=0.93). Conclusion: In beta-thalassemia minor, patients with anemia, optic disc area showed a statistically significant reduction compared to the patients without anemia. Further clinical trials on ocular blood flow and optic nerve oxygenation changes may highlight the role anemia in the optic nerve head of the beta-thalassemia minor patients.

Description: A correlation between increase in bone markers (alkaline phosphatase (ALP) and response to bortezomib in patients with multiple myeloma (MM) has been previously described. We now report results from a prospective study examining the relationship of serum PTH variation with skeletal effects and myeloma response to bortezomib treatment. Methods: Single agent bortezomib (1.3 mg/m2 patients 1–10; 1mg/m2 patient 11–20), was administered to patients with relapsed/refractory MM on days 1, 4, 8 and 11 on a 21 day interval for a total of 3 cycles; patients were not allowed to receive concurrent bisphosphonates or any other anti-myeloma drugs during the study period. Dynamic indices of bone turnover were prospectively evaluated by high-resolution microCT. Architectural parameters such as bone volume/total volume (BVTV), trabecular number (TbN), and thickness (Tb.Th) was obtained. PTH along with bone markers (osteocalcin, calcium, magnesium, phosphorus and serum creatinine) were measured on days 1, 4, 8, 11 before and after each bortezomib dose and every 4 hours thereafter, daily for the other days of the treatment cycle. Results: Seventeen patients were enrolled in the study with a median age of 63 years, 41 % were male and 3/4 of the patients previously failed high-dose chemotherapy. Histomorphometric microCT comparative analysis was completed (baseline and post-treatment) in 7 of the 17 patients enrolled in the trial. Baseline BV/TV values ranged from 13% to 90%. After 3 cycles of bortezomib treatment a statistically significant increase in BV/TV was recorded in 6 of 7 patients (P

Description: Abstract 18 Introduction: Long-term survival in pediatric relapsed AML is only 20-30%. Optimal reinduction therapy is unknown, and there is a concern about cardiotoxicity with repeated anthracycline use at relapse. Preclinical in vitro and animal studies, and limited clinical data suggest that liposomal daunorubicin (DaunoXome®, DNX) is less cardiotoxic. These considerations lead to a phase III study, in the setting of the International BFM Study Group. Materials and methods: FLAG was randomised against FLAG/DNX in the 1st reinduction course. The conventional 5-days FLAG only was recommended as the 2nd course. DNX was dosed at 60 mg/m2/day on days 1, 3 and 5. After induction, allogeneic stem cell transplantation was generally recommended, but time-to-transplant could be bridged by high- or low-intensive consolidation therapy. Primary endpoint of the study was early treatment response, based on bone marrow examination shortly before reinduction course 2, and defined as either good (≤20% leukemic blasts) or poor (〉20% leukemic blasts). This endpoint was chosen because of its prognostic value in earlier relapsed AML BFM-trials, and because compliance with an extended protocol guideline was likely to be suboptimal within the context of a highly multinational and multicenter AML Relapse protocol. However, secondary endpoints were defined, including the CR2 rate determined after 2 courses, long-term survival, and toxicity. Patients with AML M3 and those 〉18 years of age at initial diagnosis were ineligible. The study opened in most countries in 2002/2003. The study closed for accrual on April 1, 2009 when the required 360 fully eligible and evaluable patients had been randomized. Early and late relapsed AML was defined as a relapse within or after 1 year from initial diagnosis, but this only influenced treatment in that early relapsed AML patients were eligible for haploidentical SCT, while late relapsed AML patients were eligible for autologous SCT, if a matched or partly mismatched transplant was not possible. Thirteen groups from 20 countries and 〉100 centers have enrolled patients, with informed consent and after approval of the study by regulatory authorities. Data are presented according to intention-to-treat, with a median follow-up of 2.7 years for patients at risk. Results: Overall 4-year probability of survival (pOS) was 35% SE 2%, the overall CR2 rate 62%. The good early responders had a 4-year pOS of 45% SE 3% versus 10% SE 3% for poor responders (p

Description: Zinc deficiency is common in adult sickle-cell disease (SCD) patients, due to continued hemolysis and hyperzincuria. Growth retardation, hypogonadism, and immune dysfunctions due to zinc deficiency have been described in SCD patients. Our studies show that zinc has not only anti-inflammatory functions, but is also an antioxidant. We have previously shown that zinc supplementation to adult SCD patients decreased the incidences of infection and hospital admissions. We hypothesize that zinc supplementation improves T-helper cell and vascular endothelial cell activation, and decreases oxidative stress and NF-κB activation in SCD patients. To test this hypothesis, we recruited 36 ambulatory SCD (homozygous) patients (ages 18–47 years, 11 males and 7 females in each group) and randomly divided these into 2 groups. One group (n=18) received 25 mg zinc as acetate orally thrice a day for 3 months. The other group (n=18) received placebo. All these patients were free of pain crisis for 3 months and were not receiving hydroxyurea. The results indicate that zinc supplemented group had decreased incidence of infection in comparison to the placebo group (Chi square analysis: p=0.017). After 3 months of zinc supplementation, the plasma zinc level increased. The anti-oxidant power increased and the plasma levels of NO, lipid peroxidation products (MDA+HAE), DNA oxidation product (8-OHdG), and sVCAM-1 decreased in the zinc supplemented group, compared to the placebo group (p

Description: The incidence of follicular lymphoma (FL) in industrialized countries has been increasing since the 1950s. Polymorphisms in genes encoding key enzymes controlling folate-methionine metabolism, including methylenetetrahydrofolate reductase (MTHFR), methionine synthase (MS or MTR), serine hydroxymethyltransferase (SHMT), and thymidylate synthase (TS or TYMS), modify the risk of various cancers and possibly FL. This study specifically looks for an association between MTHFR, MTR, TYMS, and SHMT polymorphisms and the risk of FL. We carried out a case-control study with 172 patients diagnosed with FL and 206 control subjects. We report that the risk of FL was doubled by the association of one mutant allele at both MTHFR polymorphisms. Individuals with MTR 2756AA had 2-fold higher risk of FL, and subjects not having at least one TYMS 2R allele showed a 2-fold higher risk of FL. The MTR 2756AA genotype conferred a greater multivariate-adjusted relative risk of FL, and the risk was multiplied by almost 5 in the TYMS2R(-)/MTR 2756AA combination. In conclusion, common polymorphisms in key enzymes of the folate-methionine metabolism pathway result in an increased risk of FL and suggest that inadequate intake of dietary folate and other methyl donor nutrients may contribute to the development of this malignancy. (Blood. 2006;108:278-285)

Description: Although significant advances have been made over the last decade with respect to our understanding of stem cell biology, progress has been limited in the development of successful techniques for clinically significant ex vivo expansion of hematopoietic stem and progenitor cells. We here describe the effect of Notch ligand density on induction of Notch signaling and subsequent cell fate of human CD34+CD38– cord blood progenitors. Lower densities of Delta1ext-IgG enhanced the generation of CD34+ cells as well as CD14+ and CD7+ cells, consistent with early myeloid and lymphoid differentiation, respectively. However, culture with increased amounts of Delta1ext-IgG induced apoptosis of CD34+ precursors resulting in decreased cell numbers, without affecting generation of CD7+ cells. RNA interference studies revealed that the promotion of lymphoid differentiation was primarily mediated by Delta1 activation of Notch1. Furthermore, enhanced generation of NOD/SCID repopulating cells was seen following culture with lower but not higher densities of ligand. These studies indicate critical, quantitative aspects of Notch signaling in affecting hematopoietic precursor cell-fate outcomes and suggest that density of Notch ligands in different organ systems may be an important determinant in regulating cell-fate outcomes. Moreover, these findings contribute to the development of methodology for manipulation of hematopoietic precursors for therapeutic purposes.

Description: Background: Combined modality treatment consisting of chemotherapy (CT) followed by involved field radiotherapy (IF-RT) is the standard treatment for early unfavourable Hodgkin’s lymphoma (HL). Despite high complete remission (CR) rates, failures are common. We thus compared the baseline-dose BEACOPP regimen with ABVD and 20 with 30 Gy IF-RT in a prospectively randomized trial (HD11) in an attempt to improve outcome in this group of patients. Methods: Between May 1998 and January 2003, 1570 patients (pts) aged 16–75 with untreated intermediate stage HL (CS I, IIA with risk factors or IIB with elevated ESR and/or ≥3 nodal areas only) were randomized according to a factorial design between 4 cycles of ABVD followed by 30 Gy IF-RT (arm A - standard treatment), 4 ABVD + 20 Gy IF-RT (arm B), 4 baseline-dose BEACOPP + 30 Gy IF-RT (arm C) and 4 baseline-dose BEACOPP + 20 Gy IF-RT (arm D). Results: In the fifth preplaned interim analysis, 1293 pts were evaluable for the chemotherapy comparison and 1274 for the radiotherapy comparison. Patient characteristics were well balanced between the treatment arms. 95% of patients treated reached CR, 2% had pogressive disease, 8% relapsed and the total mortality rate was 4% with no significant differences between treatment arms for either endpoint. The most frequent haematological toxicities during chemotherapy were leucopenia observed in 32% of pts (ABVD: 25%, BEACOPP: 39%) and anemia in 4% of pts (ABVD

Description: Abstract 634 FLT3, a transmembrane receptor tyrosine kinase constitutively activated via mutation in blasts of patients (pts) with AML, is an important therapeutic target. Blasts from approximately 25% of pts have a length or internal tandem duplication (ITD) mutation in the juxtamembrane region or tyrosine kinase domain (TKD1) of FLT3, which is associated with reduced disease-free survival and overall survival (OS), particularly in pts with normal cytogenetics. Blasts from 5–10% of pts have a point mutation (typically D835Y) in the tyrosine kinase domain (TKD); the effect of this mutation on prognosis is uncertain. Midostaurin (PKC412) is a multi-targeted kinase inhibitor with demonstrated clinical activity in FLT3-mutant (FLT3–mut) and FLT3-wild-type (FLT3–wt) AML (peripheral blood blast reduction in 70% and 30% of pts, respectively) but rarely produces complete remissions). Preclinical studies demonstrated synergy between FLT3 inhibitors and chemotherapy. We conducted a Phase 1b trial to investigate the feasibility of administering daunorubicin (60 mg/m2 IV, days 1–3) and cytarabine (100 mg/m2 IVCI, days 1–7) induction and high-dose cytarabine post-remission therapy (3 gm/m2 over 3h every 12h, days 1, 3, and 5 for 3 cycles) plus oral midostaurin at 100 mg or 50 mg each twice daily on days 8–21 (sequentially) or days 1–7, 15–21 (concomitantly) with all chemo cycles in newly diagnosed pts under age 61 with de novo AML. Whereas 100 mg of midostaurin plus induction chemotherapy was poorly tolerated due to nausea and vomiting, the 40 pts who received 50 mg of midostaurin orally twice daily ( 20 each on the sequential and concomitant schedules; 27 FLT3–wt; 13 FLT3–mut [9 with an ITD]), tolerated the combination well. Median midostaurin exposure was 133 days (range 21–975) for the FLT3–mut pts and 90 days (range 7–1016) for FLT3–wt pts. Maintenance therapy with midostaurin was allowed with investigator discretion and was received by 5 pts (3 FLT3–mut, 2 FLT–wt). The median ages for the FLT3–wt and FLT3–mut pts were 50 years (range 25–60) and 46 years (range 20–65), respectively. 77% of the FLT3–mut pts displayed normal, 15% adverse and 8% other intermediate cytogenetics compared with 18.5%, 26%, and 26%, respectively, for FLT3-wt (also 18.5% favorable; 11% unknown). Complete response occurred in 32/40 (80%) of all pts (20/27 [74%] of FLT3–wt patients, 12/13 [92%] of FLT3–mut pts). Patients were censored at the last date they were known to be alive with a median post treatment follow-up for FLT3-mut pts of 1059 days and 1086 days for FLT3-wt. Even accounting for their differing cytogenetics and ages, the OS of the FLT3–mut subgroup was expected to be inferior to that of the FLT3–wt subgroup. However, we report that the 1 and 2 year OS for the pts with FLT3–mut AML was 85% and 62%, respectively, and was comparable to that of the FLT3–wt subgroup (81% and 59%, respectively). Although based on small numbers and not stratified for type of FLT3 mutation (TKD, ITD, ITD length, location, or allelic ratio), these long-term results suggest that combination therapy with a FLT3 inhibitor and chemotherapy might be effective enough to obviate the perceived need for allogeneic stem cell transplantation for FLT3–mut AML pts in first complete remission. Moreover, these data support the rationale for the ongoing international phase 3 study of induction, post-remission intensification, and maintenance with midostaurin (50 mg po bid) or placebo. Disclosures: Stone: Novartis: Research Funding, ad hoc consultancy; Cephalon: ad hoc consultancy. Off Label Use: midostaurin with chemothereapy for AML. Paquette:Novartis: Honoraria, Research Funding, Speakers Bureau. Schiller:Novartis: Research Funding, Speakers Bureau; Millenium: Research Funding, Speakers Bureau; Genzyme: Research Funding; Vion: Research Funding; Centocor: Research Funding; Eli Lilly: Research Funding; Celgene: Research Funding. Schiffer:Novartis: Consultancy, Research Funding; Genzyme: Consultancy. Ehninger:Novartis: Honoraria, Research Funding. Cortes:Novartis: Research Funding; Bristol-Myers Squibb: Research Funding; Wyeth: Research Funding. Kantarjian:Novartis: Research Funding. DeAngelo:Bristol-Myers Squibb: Speakers Bureau; Celgene: Speakers Bureau; Enzon: Speakers Bureau; Novartis: Speakers Bureau. Huntsman-Labed:Novartis: Employment, Equity Ownership. Dutreix:Novartis: Employment, Equity Ownership. Rai:Novartis: Employment, Equity Ownership. Giles:Novartis: Research Funding; Merck: Research Funding; Bristol-Myers Squibb: Research Funding; Vion: Research Funding.

Description: A severely reduced ADAMTS13 activity due to inhibitory autoantibodies is a key feature of acquired thrombotic thrombocytopenic purpura (TTP), leading to the persistence of ultralarge VWF multimers, platelet aggregation and disturbance of microcirculation. We followed 39 patients (8 male, 31 female, mean age 38 years) with clinical signs of TTP over a period between 5 days to 16 years and observed a total of 53 episodes of TTP. ADAMTS13 was measured with a collagen-binding assay and the FRETS-VWF73 based Technozym ADAMTS-13 assay (activity and antigen, respectively). ADAMTS13 inhibitor was measured with a modified Bethesda method with both the above mentioned assays, and with the Technozym ADAMTS-13 INH ELISA. Thirty-one patients had autoimmune TTP, and 47 episodes of TTP were analyzed in these patients. In all acute episodes, ADAMTS13 activity was below the detection limit (0.2 U/ml in 66% of the episodes (after median 160 days). In the remaining cases anti-ADAMTS13 antibodies persisted during remissions for up to 2 years. In 3 cases the antibody reoccurred after initial normalization of ADAMTS13 activity, and clinical relapses followed. In total, 21 relapses were observed after a median of 46 months (range 1– 87), all associated with low ADAMTS13 levels. Rituximab was given in 7 cases of relapsing TTP and resulted in complete, durable clearance of the antibodies in 100%. Determination of ADAMTS13-related parameters is useful to distinguish between autoimmune, hereditary, and secondary forms of TTP and to choose an appropriate therapy. It is also useful to predict the risk of relapse in patients with TTP in remission.

Description: Leukostasis, a life-threatening complication of acute leukemia, occurs when leukemia cells obstruct the circulation of vital organs like the brain and lungs leading to intracranial hemorrhage or respiratory failure. Although the pathophysiology of leukostasis is poorly understood, an elevated concentration of circulating leukemia cells, pathologic adhesion, and decreased cell deformability are thought to play significant roles. Clinical deterioration can occur soon after chemotherapy is initiated, suggesting that chemotherapy itself may be a risk factor for leukostasis. To investigate the effects of chemotherapy on cell stiffness, we performed serial single cell deformability measurements with an atomic force microscope (AFM), a commonly used tool in nanoscience for imaging and characterizing mechanical properties of materials on a submicron level, and modified the AFM to operate in cell culture conditions at 37°C. Leukemia cells from patients with acute lymphoblastic leukemia and acute myeloid leukemia as well as leukemia cell lines were incubated with chemotherapeutic agents, and changes in cell stiffness were tracked over time with AFM as the cells underwent chemotherapy-induced cell death. In the presence of dexamethasone or daunorubicin, leukemia cells exhibited increases in stiffness by as much as two orders of magnitude. Cell stiffness appeared to increase before caspase activation and peaked after completion of cell death, and the rate at which cell stiffness increased was dependent on chemotherapy type. Stiffening with cell death was found to occur for all cell types and chemotherapies investigated and is due, at least in part, to dynamic changes in the actin cytoskeleton. This observed correlation between cell death and cell stiffening may partially explain why some leukemia patients develop leukostasis shortly after starting chemotherapy, and it suggests that leukocytoreduction should remain an important treatment for hyperleukocytosis in acute leukemia. Figure 1. Average apparent stiffness of dead (dark gray) leukemic cells exposed to chemotherapy is significantly higher compared to untreated (light gray) cells (n 〉 15, p 〈 0.05 for all comparisons of dead/untreated populations). (A) Primary ALL cells and lymphoid leukemic cell lines exposed to 1 μM dexamethasone (B) Primary AML and myeloid leukemic cell lines exposed to 1μM daunorubicin. Error bars are standard error. Figure 1. Average apparent stiffness of dead (dark gray) leukemic cells exposed to chemotherapy is significantly higher compared to untreated (light gray) cells (n 〉 15, p 〈 0.05 for all comparisons of dead/untreated populations). (A) Primary ALL cells and lymphoid leukemic cell lines exposed to 1 μM dexamethasone (B) Primary AML and myeloid leukemic cell lines exposed to 1μM daunorubicin. Error bars are standard error. Figure 2. Apparent stiffness of leukemic cells increases with progression of cell death. (A) A typical stiffness trace of a single M5 AML cell exposed to 1μM daunorubicin (circles). The apparent stiffness of a typical control cell remains relatively constant (triangles) and does not undergo apoptosis or cell death during the course of the experiment. Transition from open to filled shapres represents onset of cell death. Early apoptosis is defined as caspase 3 or 7 postivie staining and late apoptosis/dead is defined as Sytox Green (marker for cell membrane integrity loss) positive staining. (B) From the same patient sample, the average apparent stiffness of a population of late apoptotic/dead AML cells was significantly stiffer than early apoptopic cells and controls (n = 15, p〈 0.05). Error bars are standard error. Figure 2. Apparent stiffness of leukemic cells increases with progression of cell death. (A) A typical stiffness trace of a single M5 AML cell exposed to 1μM daunorubicin (circles). The apparent stiffness of a typical control cell remains relatively constant (triangles) and does not undergo apoptosis or cell death during the course of the experiment. Transition from open to filled shapres represents onset of cell death. Early apoptosis is defined as caspase 3 or 7 postivie staining and late apoptosis/dead is defined as Sytox Green (marker for cell membrane integrity loss) positive staining. (B) From the same patient sample, the average apparent stiffness of a population of late apoptotic/dead AML cells was significantly stiffer than early apoptopic cells and controls (n = 15, p〈 0.05). Error bars are standard error.

Description: Abstract 2168 Poster Board II-145 The deregulated tyrosine kinase associated with t(9;22) fusion protein BCR-ABL is efficiently targeted by tyrosine kinase inhibitors (Imatinib, Nilotinib and Dasatinib). It is generally believed that most patients have residual disease. The inability to eliminate the refractory leukemia stem cell in chronic myeloid leukemia (CML) is not well understood. The refractory stem cell is present despite effective inhibition of the BCR-ABL kinase in these cells, and dissociation between kinase inhibition and cell death implies lack of dependency on BCR-ABL aberrant kinase activity, unlike the one seen in more mature CML cells. Thus the oncogene addictive dependency of these leukemia stem cells may be overcome by intrinsic and/or extrinsic factors/pathways. One such pathway involved in hematopoeitic stem cell maintenance is the Wnt/β-catenin signaling pathway. BCR-ABL signaling is known to directly activate the Wnt/β-catenin pathway. The loss of function of a negative regulator of the Wnt/β-catenin pathway, known as GSK3β is associated with CML progression from chronic phase to the blast phase. Lastly, the loss of β-catenin in murine models impairs the self renewal capacity of both the normal and the BCR-ABL+ leukemia stem cell. Thus this pathway is important during various stages of the disease. We explored the effect of Wnt inhibition using a novel Wnt pathway inhibitor (AG-214, University of Michigan). AG-214 is structurally related to a previously reported Wnt-inhibitor. AG-214 is able to antagonize β-catenin/TCF in luciferase reporter assays, and expression of Wnt targets in colon cancer cell lines. We utilized a serum free culture system with 5 added cytokines and treated both CML blast crisis CD34+ as well as chronic phase CD34+ cells with AG-214. Our in vitro experiments show that primary blast crisis CD34+ cells are induced to undergo apoptosis at an IC-50 of approximately 2 μM. Furthermore, combination of 1.25 μM of AG-214 with 2 μM Imatinib achieved greater than 50% apoptosis. Analysis of chronic phase CML CD34+ cells showed that targeting of Wnt/β-catenin pathway requires higher concentration of the Wnt-inhibitor (〉2.5 μM), and that the addition of Imatinib can cooperate to enhance the apoptotic response. Furthermore, chronic phase progenitors (Lin-CD38+/CD34+) are more sensitive to lower concentrations of AG-214 whereas 5 μM is required to induce significant apoptosis of ∼70% in the primitive leukemia stem cell (Lin-/CD38-/CD34+) population, and addition of 2 μM Imatinib increased their apoptotic response to ∼84%. Normal CD34+ cells do not undergo significant apoptosis with 5 μM of AG-214 (∼10%) even when combined with 2 μM Imatinib (∼20%). Targeting of the Wnt/β-catenin pathway enhances apoptosis in both blast crisis and chronic phase CML progenitors and leukemia stem cells. Disclosures: No relevant conflicts of interest to declare.

Description: GA101 is a novel monoclonal antibody of IgG1 type which binds with high affinity and selectivity to the extracellular domain of the human CD20 antigen on B cells. In contrast to rituximab which is a chimeric antibody and recognizes a type I epitope, GA101 is humanized and recognizes a type II epitope which is also localized in the extracellular loop of CD20. The recognition of the type II epitope together with a modification of the elbow hinge region results in enhanced direct non-caspase dependent cell death induction, and concomitant reduction in CDC upon binding to CD20. In addition, using GlycoMab technology, the Fc-region of GA101 was glycoengineered to contain bisected, afucosylated carbohydrates. As a result GA101 has increased affinity for the low and high affinity FcγRIIIa receptor expressed on natural killer cells, macrophages and monocytes. Consequently, GA101 mediated a 5–50 fold enhanced induction of effector cell mediated ADCC. In B-cell depletion assays with whole blood from healthy donors, an assay combining all mechanisms of action, GA101 was significantly more potent and efficacious in depleting B cells than rituximab. In preclinical NHL testing these properties translated into superior anti-tumoral efficacy of GA101 in direct comparison to rituximab against a number of aggressive NHL xenograft models. In cynomolgus monkeys the induction of B cell depletion mediated by GA101 and subsequent B cell recovery were investigated. GA101 induced complete, rapid and long-lasting B cell depletion both in peripheral blood and in lymphoid tissue e.g. spleen and lymph nodes. The efficacy of GA101 (10 and 30 mg/kg) at depleting B cells in different lymphoid tissues of cynomolgus monkeys was compared with that of rituximab (10 mg/kg) following 2 i.v. doses administered on days 0 and 7. Notably, GA101 showed statistically superior depletion of total B cells from lymph nodes compared to Rituximab from day 9 to 35 onwards with B cell numbers decreased by over 95%. These results demonstrated that GA101 was more efficacious at depleting B cells from lymph nodes and spleen of cynomolgus monkeys compared to rituximab. Compared to existing antibodies, GA101 constitutes the first type II CD20 antibody engineered for increased ADCC with significantly enhanced efficacy in a variety of preclinical models. Based on these data it is assumed that the combination of the recognition of a type II epitope together with improved ADCC potency might translate into superior efficacy in the clinical treatment of CD20 positive malignant diseases.

Description: Polycythemia vera (PV) and essential thrombocythemia (ET) are two common types of myeloproliferative disorders (MPD). The prevalence of PV and ET in the United States (US) has not been well documented. Recent breakthroughs in the molecular etiology of these disorders and the accelerated development of targeted pharmacotherapeutics to treat the MPD have significantly increased the need to accurately define the affected population. In the present study, we obtained detailed demographic and health claims data from major commercial insurance payers in Connecticut and the Center for Medicare and Medicaid Services to estimate the prevalence of PV and ET. Health claims data from one payer and the actual diagnoses made by physicians who submitted claims with MPD-related ICD-9 codes were utilized to develop claim-based statistical algorithms to predict the probability that an individual with claims suggestive of MPD truly has PV or ET. Specifically, logistic regression was used to develop the algorithms, and area under the receiver operating characteristics curve (AUC) was used as the measure of goodness-of-fit for each model. Different models were fit, and the model with the highest AUC was selected. For PV, the best-fitting model included age as a continuous variable and the frequency of two PV-related ICD-9 codes (238.4 and 289.6 combined) as a continuous variable, and the AUC was 0.95. For ET, the best-fitting model included age as a continuous variable and the frequency of code 289.9 as a categorical variable (=0, =1, or ≥2), and the AUC was 0.72. For both models, the addition of gender or the frequency of the non-specific code 238.7 did not improve AUC. Subsequently, the algorithms were applied to health claims from multiple payers to estimate the number of PV and ET patients in Connecticut. The total number of Connecticut residents included in the study was close to 2,900,000, which represented about 83.2% of the estimated population of the entire state in July 2003. As of 2003, the age-standardized prevalence of PV and ET in Connecticut was 22 per 100,000 and 24 per 100,000, respectively. Applying the age-specific prevalence of PV and ET to the entire US population resulted in an estimated total of 65,243 patients with PV and 71,078 patients with ET in the US in 2003. This study is the first to assess the prevalence of PV and ET in a very large US population. Given the large number of individuals afflicted with these diseases and the fact that demographic changes alone will further increase the burden of these diseases in the foreseeable future, it is imperative to conduct more systematic research into the etiology and treatment of PV and ET.

Description: Background: Neurologic complications of multiple myeloma (MM) are numerous, however little is known about strokes occurring in the course of MM and its treatment. Methods: 2877 MM patients were seen for an initial evaluation at our institution over a 5-year period (1998–2002). Patients were identified using discharge summaries by combining ICD-9 codes for MM and stroke. They were included if they had clinical and radiological features of acute stroke. Ischemic stroke was defined as a new acute neurologic deficit lasting 〉 24 hours, irrespective of diffusion-weighted MRI results. Diagnosis of hemorrhagic stroke was made in patients with new acute neurologic deficit plus evidence of hemorrhage on CT scan. We retrospectively reviewed medical records for demographics, type of MM and treatment, stroke type, clinical features, relevant imaging and laboratory data, and outcomes. Results: The 11 patients that we identified included eight with ischemic strokes and three with subarachnoid hemorrhages (SAH). There were no patients with intraparenchymal hemorrhage. The overall incidence of stroke in this cohort was 76/100,000 per year, whereas the incidence of ischemic stroke was 56/100,000 per year. The mean age of patients with ischemic stroke was 59 years. Seven had one or more stroke risk factors and an equal number had received thalidomide. The latter were given small doses of coumadin as part of the treatment protocol; at the time of the stroke, INR range was 0.9–1.4. Based on clinical, radiological and other laboratory features, of the eight patients with ischemic strokes, two were presumed cardio-embolic (one had infective endocarditis), five were thrombotic, and one was caused by hypoperfusion. Two patients had findings of severe stenosis/occlusion in vessels corresponding to the infracted brain territory (internal carotid and basilar arteries). Two patients had documented normal plasma viscosity and three had evidence of extra-cranial thrombosis at the time of the stroke. In the three patients with SAH, hemorrhage occurred in the setting of trauma and thrombocytopenia, although one patient had an incidental anterior communicating artery aneurysm. Seven patients were left with minor or no deficits and four died, two in each of the groups. Conclusion: Overall, strokes did not appear to be more common in MM patients than in the general population, and the pathophysiology was likewise, not different than in patients without MM, with the exception of one patient with infective endocarditis, which is probably directly related to MM or its treatment. The highly selected referral population at our myeloma institute, and the retrospective nature of the study probably underestimate the incidence of stroke. The role of thalidomide in stroke remains unknown. Thrombocytopenia and trauma are probable risk factors for subarachnoid hemorrhage in MM patients. Fatal outcomes were frequent, but when death did not occur, the deficits were minor.

Description: Recent advances in the diagnosis, molecular pathogenesis, classification and therapy have been made in the field of myelodysplastic syndrome (MDS) and juvenile myelomonocytic leukemia (JMML) in childhood. We report a retrospective analysis of children with MDS and JMML diagnosed between 2001 and 2006 in Korea. In total, 135 patients were enrolled from 19 major hospitals with pediatric hematology oncology clinics: MDS, 96 (primary MDS, 77; constitutional anomalies with MDS, 13; treatment-related MDS, 6) and JMML, 39. The incidence of MDS/JMML was around 22.5/year, which is about 6% of childhood leukemia. Various classification systems including FAB, WHO, IPSS, CCC system, and pediatric adjustment of the WHO classification were applied. The median ages at diagnosis were 68 and 10 months in MDS, and JMML, respectively. Males dominated in JMML. Cytogenetic abnormalities were observed in 43% of MDS (monosomy 7, 5; trisomy 8, 3) and in 10% of JMML. Treatment was chosen by each institute’s preference: 34 patients with MDS received AML-type intensive chemotherapy, with complete remission rate of 82.0%. The 5-year Kaplan-Meier overall survival rate was 54% each for MDS and JMML. Survival of MDS patients was influenced by the marrow blast % (P = 0.007) and disease category (P= 0.006). Stem cell transplantations (SCT) were undertaken in 56 patients (MDS, 29; JMML, 27). The sources of stem cells were: bone marrow, 36; umbilical cord, 18; peripheral blood, 2). Matched related transplants were 9 cases. Conditioning was various, but BuCy based regimen was used in 68.4%. Acute GvHD ≥ Grade II was found in 43.8% and chronic GvHD in 35.1%. The 5-year Kaplan-Meier overall survival rate was 55% for MDS, and 57% for JMML. Survival after unrelated transplant was comparable with that of matched related transplants. This analysis inspired the necessity of nation-wide prospective studies in Korea, including morphologic study by a central pathology review board, epidemiologic study, molecular pathophysiologic study, and therapeutic trials incorporating SCTs, or new drugs.

Description: The somatic mutation JAK2 V617F has been identified as a pathogenic factor in typical chronic myeloproliferative diseases (MPD) such as polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis with myeloid metaplasia (MMF). In typical forms of myelodysplastic syndromes (MDS), JAK2 V617F mutation is rarely present (2–5%); on the contrary, it has been found with higher prevalence in patients with RARS-T (i.e. MDS/MPD-U with platelet count 〉600×109/L and ringed sideroblasts more than 15%) and in a subgroup of MDS patients with isolated 5q deletion and a proliferative bone marrow. In this study we analysed the JAK2 V617F mutational status in 53 MDS patients (26 males, 27 females; median age at the time of the study 76 years, range 45–91). Patients were classified as follows: 4 cases 5q- syndrome, 3 RCMD, 5 MDS/MPD, 1 MDS-U, 23 RA, 12 RARS, 5 RAEB. DNA was extracted from purified granulocytes; all samples were analyzed by allele-specific polymerase chain reaction (PCR), according to Baxter el al (2005). DNA samples were further subjected to direct sequencing for confirmatory testing. The JAK2 V617F mutation was present in 3 cases, with an overall frequency of 5%. With respect to MDS subtype, 1 patient had RA and 2 RARS. Among the 12 RARS patients, the two V617F postive displayed thrombocytosis (680×109/L and 649×109/L), whereas none of the 10 RARS V617F negative patients showed high platelet counts (median Plt 157×109/L, range 5–422×109/L). In one JAK2 mutant case, thrombocytosis required treatment with hydroxyurea. Moreover, the two V617F positive RARS patients displayed higher WBC count (6.2×109/L and 8.5×109/L) than the V617F negatives (median WBC 4.05×109/L); no difference was observed in Hb levels. The JAK2 positive RA patient had 10% of sideroblasts in bone marrow, normal platelet and WBC count and no proliferative characteristics; since the occurrence of the mutation may be an early event and preceed the classical manifestations of MDS/MPD, a longer follow-up is necessary to determine its possible prognostic significance. Considering the V617F negative MDS cases, only one patient, diagnosed as MDS/MPD, showed a platelet count 〉600×109/L. In conclusion, we confirmed recent reports showing that JAK2 V617F is present with low prevalence (about 5%) in MDS; in particular, the JAK2 mutation identifies a subset of MDS patients with and “overlap” syndrome, characterised by proliferative bone marrow morphology and frequent thrombocytosis and leucocytosis, who may benefit from JAK2 specifically targeted therapies.

Description: The simultaneous manifestation of different lymphomas in the same patient or in the same tissue is defined composite lymphoma. Although reports of synchronous or metachronous Hodgkin’s lymphoma (HL) and Non Hodgkin’s lymphoma (NHL) are not uncommon in the literature, the biologic relationship of the 2 malignancies is often unclear. Primary cutaneous B-cell lymphomas (pCBCLs) have been recognized as distinct clinicopathologic entities; they represent a wide spectrum of lymphoproliferative disorders separated from of B-cell NHL secondarily involving the skin and cutaneous B-cell pseudolymphomas. As regarding pCBCLs, a concomitant diagnosis of HL has been described very rarely. This is the case of a caucasian man affected by primary cutaneous follicolar B cell lymphoma (pCFCL). He presented grouped red plaques located on the nape, abdomen, shoulders, arms and even some little tumors surrounded by erythematous papules. Complete staging procedures did show no evidence of extracutaneous disease. A subcutaneous interferon therapy was started, in some months the patient reached a complete remission, and a maintainance therapy was continued for about 2 years. After 15 years, at the age of 58, the patient presented a red to violaceous infiltrated solitary plaque on the back, appeared about 2 months before. The lesion was completely excised and the biopsy showed a diffuse dermal infiltrate, not involving the epidermis, structured in follicle with reactive germinal centers; they were surrounded by small sized monomorphic lymphocytes with irregular nuclei and pale cytoplasm, showing the following immunophenotype pattern: CD20+, CD3−, IRTA+, CD10−, BCL6−, BCL2+, low proliferative index. A plasmacellullar CD138+ and CD79a+ population was at the periphery of the infiltrates, with monotypic expression of cytoplasmic k chain. The whole picture was interpreted as primary cutaneous marginal zone B-cell lymphoma (pCMZL). The association with Borrelia burgdorferi infection, sometimes described in pCMZL, wasn’t demonstrated. The patient presented a large right axillary lymph node that was excised and found to be unexpectly infiltrated by HL, mixed cellularity subtype. The patient underwent a standard baseline staging procedure with total body CT scan and bone marrow trephine biopsy; the latter resulted negative; the t(11;14) and t(14;18) rearrangements weren’t demonstrated in bone marrow; the CT did show no other suspected masses nor lymphoadenopathy, besides the clinically evident right axillary lymph node. A 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) revealed sites of hyperactivity in the same right axillary region, but extending to the subclavian region and the thoracic region. The patient started chemoterapy (ABVD regimen), and at the end of 4 courses a whole body CT scan and FDG-PET resulted both negative. Now he is being treated with radiotherapy. If the nodal malignancy would have been diagnosed first, the skin lesion probably could have been misinterpreted as a secondary localization of HL; if the node biopsy wouldn’t have been performed we could diagnose B-cell NHL secondarily involving the skin (stage IV). Nevertheless the cutaneous and nodal infiltrates had a completely different general picture and phenotype. This case probably reflects a HL after 15-year remission of a pCBCL of low grade and the relationship between HL and the preceding pCFCL is not clear: casual or related to genetic predisposition for oncogenic events or favoured by an immunodeficiency state related to the first disease and the previous immunomodulatory therapy.

Description: Although well characterized in the mouse, the role of Notch signaling in the human T-cell receptor αβ (TCR-αβ) versus TCR-γδ lineage decision is still unclear. Although it is clear in the mouse that TCR-γδ development is less Notch dependent compared with TCR-αβ differentiation, retroviral overexpression studies in human have suggested an opposing role for Notch during human T-cell development. Using the OP9-coculture system, we demonstrate that changes in Notch activation are differentially required during human T-cell development. High Notch activation promotes the generation of T-lineage precursors and γδ T cells but inhibits differentiation toward the αβ lineage. Reducing the amount of Notch activation rescues αβ-lineage differentiation, also at the single-cell level. Gene expression analysis suggests that this is mediated by differential sensitivities of Notch target genes in response to changes in Notch activation. High Notch activity increases DTX1, NRARP, and RUNX3 expression, genes that are down-regulated during αβ-lineage differentiation. Furthermore, increased interleukin-7 levels cannot compensate for the Notch dependent TCR-γδ development. Our results reveal stage-dependent molecular changes in Notch signaling that are critical for normal human T-cell development and reveal fundamental molecular differences between mouse and human.

Description: During surface-initiated blood coagulation in vitro, activated factor XII (fXIIa) converts factor XI (fXI) to fXIa. Whereas fXI deficiency is associated with a hemorrhagic disorder, factor XII deficiency is not, suggesting that fXI can be activated by other mechanisms in vivo. Thrombin activates fXI, and several studies suggest that fXI promotes coagulation independent of fXII. However, a recent study failed to find evidence for fXII-independent activation of fXI in plasma. Using plasma in which fXII is either inhibited or absent, we show that fXI contributes to plasma thrombin generation when coagulation is initiated with low concentrations of tissue factor, factor Xa, or α-thrombin. The results could not be accounted for by fXIa contamination of the plasma systems. Replacing fXI with recombinant fXI that activates factor IX poorly, or fXI that is activated poorly by thrombin, reduced thrombin generation. An antibody that blocks fXIa activation of factor IX reduced thrombin generation; however, an antibody that specifically interferes with fXI activation by fXIIa did not. The results support a model in which fXI is activated by thrombin or another protease generated early in coagulation, with the resulting fXIa contributing to sustained thrombin generation through activation of factor IX.

Description: Tyrosine kinase inhibitors (TKI) selective for Bcr-Abl, such as dasatinib, imatinib, and nilotinib have had remarkable success in the clinic, potentially shifting the prognosis of chronic myelogenous leukemia (CML) to a manageable chronic disease. With the increase in longevity of CML patients, there is rising concern of co-morbidities that may be influenced by chemotherapy (Force et al., Nature Rev.2007;7:332–340). Recently, congestive heart failure (CHF) and direct cellular cardiotoxicity have been reported in CML patients on imatinib therapy (Kerkela et al., Nature Medicine2006;12:908–916). Ultrastructural mitochondrial abnormalities in cardiomyocytes were observed in CML patients with severe CHF and, interestingly, similar abnormalities were observed in cardiomyocytes of imatinib-treated mice, thus providing a prospective in vivo animal model for imatinib-induced cardiotoxicity. Furthermore, correlative findings of mitochondrial membrane potential loss, decreased cell viability, and increased apoptosis resulted from an array of cell-based assays in imatinib-treated primary rat cardiomyocytes, consequentially affording a supportive, if not predictive, in vitro cardiomyocyte toxicity model. Since imatinib-induced inhibition of the native form of c-Abl kinase was speculated to cause the observed cardiotoxicity and c-Abl is a shared target of dasatinib, imatinib, and nilotinib, the in vitro cardiotoxicity potential of dasatinib and nilotinib at pharmacologically relevant concentrations (0.09 μM and 5 μM, respectively) and up to 10-fold higher concentrations were compared side-by-side with imatinib in primary rat cardiomyocytes. Dasatinib did not significantly affect mitochondrial membrane potential, cell viability, apoptosis, or cellular ultrastructure in vitro, whereas imatinib significantly affected these parameters. Nilotinib at pharmacologically relevant concentration demonstrated decreased cell viability, but differed from imatinib in that mitochondrial membrane potential integrity was not affected under identical experimental conditions. Results suggest that at pharmacologically relevant concentrations, dasatinib does not induce cardiotoxicity, as does imatinib and nilotinib, and the molecular mechanisms of the observed cardiotoxicities may differ between imatinib and nilotinib. Of indirect relation, results from assessing another cardiovascular liability, namely hERG K+ channel blockade, demonstrated that dasatinib, imatinib and nilotinib differentially inhibited the hERG currents in vitro with IC50 of 14.3, 15.6 and 0.66 μM, respectively. These in vitro findings occurred at concentration levels approximately 150, 3 and 0.1-fold the expected human Cmax for the three TKIs, respectively. Thus, although TKI therapies may share similar targeting and clinical indications, differentiating specific toxicity profiles may be predictive of differences in potential clinical adversities.

Description: Myeloproliferative diseases (MPDs) represent the commonest cause of splanchnic vein thrombosis (SVT), including Budd-Chiari syndrome (BCS) and portal vein thrombosis (PVT), but their diagnosis is hampered by changes secondary to portal hypertension, while their influence in the outcome of SVT remains unclear. We assessed the diagnostic and prognostic value of JAK2 and MPL515 mutations in 241 SVT patients (104 BCS, 137 PVT). JAK2V617F was found in 45% of BCS and 34% of PVT, while JAK2 exon 12 and MPL515 mutations were not detected. JAK2V617F was found in 96.5% of patients with bone marrow (BM) changes specific for MPD and endogenous erythoid colonies, but also in 58% of those with only one feature and in 7% of those with neither feature. Stratifying MPD diagnosis first on JAK2V617F detection would have avoided BM investigations in 40% of the patients. In BCS, presence of MPD carried significantly poorer baseline prognostic features, required hepatic decompression procedures earlier, but had no impact on 5-year survival. Our results suggest that JAK2V617F testing should replace BM investigations as initial test for MPD in patients with SVT. Underlying MPD is associated with severe forms of BCS, but current therapy appears to offset deleterious effects of MPD on the medium-term outcome.

Description: The ability of CD8+ T cells to engage a diverse range of peptide–major histocompatibility complex (MHC) complexes can also lead to cross-recognition of self and nonself peptide-MHC complexes and thus directly contribute toward allograft rejection or autoimmunity. Here we present a novel form of cross-recognition by herpes virus–specific CD8+ cytotoxic T cells that challenges the current paradigm of self/non-self recognition. Functional characterization of a human leukocyte antigen (HLA) Cw*0602-restricted cytomegalovirus-specific CD8+ T-cell response revealed an unusual dual specificity toward a pp65 epitope and the alloantigen HLA DR4. This cross-recognition of HLA DR4 alloantigen was critically dependent on the coexpression of HLA DM and was preferentially directed toward the B-cell lineage. Furthermore, allostimulation of peripheral blood lymphocytes with HLA DRB*0401-expressing cells rapidly expanded CD8+ T cells, which recognized the pp65 epitope in the context of HLA Cw*0602. T-cell repertoire analysis revealed 2 dominant populations expressing T-cell receptor beta variable (TRBV)4-3 or TRBV13, with cross-reactivity exclusively mediated by the TRBV13+ clonotypes. More importantly, cross-reactive TRBV13+ clonotypes displayed markedly lower T-cell receptor binding affinity and a distinct pattern of peptide recognition, presumably mimicking a structure presented on the HLA DR4 allotype. These results illustrate a novel mechanism whereby virus-specific CD8+ T cells can cross-recognize HLA class II molecules and may contribute toward allograft rejection and/or autoimmunity.

Description: Recent studies suggested that JAK2V617F mutation is frequent in patients with splanchnic vein thrombosis (SVT) but not in patients with other venous thromboembolic events (VTE). However, whether screening for the JAK2V617F mutation in VTE patients is justified remains unclear. Therefore, we performed a systematic review to assess the frequency of JAK2 mutation in VTE patients and the role of JAK2V617F mutation in the diagnosis of myeloproliferative neoplasms. MEDLINE and EMBASE databases were searched. Two reviewers independently performed study selection and extracted study characteristics. Pooled odds ratios of case-control studies and weighted mean proportion of the prevalence of JAK2V617F mutation of uncontrolled series were calculated. Twenty-four studies involving 3123 patients were included. Mean prevalence of JAK2 mutation was 32.7% (95% confidence interval, 25.5%-35.9%) in SVT patients. JAK2 mutation was associated with increased risk of SVT (odds ratio, 53.98; 95% confidence interval, 13.10-222.45). Mean prevalence of JAK2 mutation in other VTE patients was low (range, 0.88%-2.57%). Presence of JAK2V617F mutation in SVT patients was associated with a subsequent diagnosis of myeloproliferative neoplasm in many patients. JAK2 mutation is strongly associated with SVT, and routine screening of JAK2 mutation appears to be indicated in these patients.

Description: FTY720, a potent immunomodulatory drug in phase 2/3 clinical trials, induces rapid and reversible sequestration of lymphocytes into secondary lymphoid organs, thereby preventing their migration to sites of inflammation. As prerequisite for its function, phosphorylation of FTY720 to yield a potent agonist of the sphingosine-1-phosphate receptor S1P1 is required in vivo, catalyzed by an as-yet-unknown kinase. Here, we report on the generation of sphingosine kinase 2 (SPHK2) knockout mice and demonstrate that this enzyme is essential for FTY720 phosphate formation in vivo. Consequently, administration of FTY720 does not induce lymphopenia in SPHK2-deficient mice. After direct dosage of FTY720 phosphate, lymphopenia is only transient in this strain, indicating that SPHK2 is constantly required to maintain FTY720 phosphate levels in vivo.

Description: The application of allogeneic stem cell transplantation (alloSCT) is limited by graft-versus-host disease (GVHD). GVHD can be divided into acute and chronic forms that likely have different requirements for initiation and pathogenesis mechanisms. In prior studies we demonstrated that residual host antigen-presenting cells (APCs) were required to initiate acute GVHD (aGVHD) mediated by CD8 T cells. In contrast, here we demonstrate that either donor or host APCs can initiate CD4-mediated GVHD in a model that has features of chronic GVHD (cGVHD). Both donor and host APCs must provide CD80/86-dependent costimulation to elicit maximal cGVHD, and there is no GVHD when both donor and host lack CD80/86. Finally, we were surprised to find that, although either donor or host APCs are sufficient to stimulate skin cGVHD, donor APCs play a dominant role in intestinal cGVHD. Both CD40 and CD80/86 are critical for donor APC function in intestinal cGVHD, but only CD80/86 is required for skin cGVHD. Thus, there are target-tissue–specific differences in APC requirements. These results identify differences in APC requirements between CD8-mediated aGVHD and CD4-mediated cGVHD. They further highlight donor APCs as additional targets for GVHD therapy.

Description: Abstract 3441 Poster Board III-329 Background CLL is characterized by the progressive accumulation of monoclonal B lymphocytes. One theory to explain how CLL cells avoid elimination through immune surveillance mechanisms is through a defect in the ability of T-cells to form immunological synapses with antigen-presenting tumor B-cells (Ramsay et al JCI 2008). Lenalidomide is an immunomodulatory agent with clinical activity in the treatment of B-cell malignancies. Recent laboratory studies showed that lenalidomide not only stimulates T- and natural killer (NK)-cell-mediated ADCC, it also restores the T-cell-mediated ability to form immunological synapses with CLL tumor cells. Since NK cells also exert cytotoxicity through immune synapse formation, here we explore how lenalidomide affects NK-cell-mediated cytotoxicity mechanisms and whether this activity is altered in the presence of rituximab since published studies showed that lenalidomide-pretreated B-cells have a down-regulated surface CD20 expression. Further, we investigated the molecular events associated with immune synapse formation and the effect of lenalidomide. Methods Immune synapse formation was assessed in NK cells (from healthy donors PBMCs) co-cultured with either B-CLL cells derived from pts or with K562 cells (positive control). Cells were fixed and the ability to form synapses was assessed via immunohistochemisty co-staining for either F-actin and CD2, or F-actin and perforin (a cytolytic protein found in NK cells). Synapse formation was visualized by microscopy and measured via relative mean fluorescent intensity. Activity of RhoA, Rac1, Cdc42 were measured using Rho GTPases assay kits. Inhibition of lenalidomide-mediated immune synapse activity was assayed using the cell permeable Rho inhibitor C3 (0.5 mM). Flow cytometry was used to measure changes in surface CD20 and CD54 (ICAM-1) expression in B-CLL samples from 3 pts after treatment with lenalidomide. Results Lenalidomide induced the formation of immunological synapses between NK cells and primary B-CLL cells (p

Description: The incorporation of blood-borne forms of tissue factor (TF) into a growing blood clot is necessary for normal fibrin generation and stabilization of the blood clot. Tissue factor pathway inhibitor (TFPI) is the primary physiologic inhibitor of tissue factor and is present within platelets. Expression of TFPI on the platelet surface may be the optimal location for it to abrogate blood-borne TF activity that incorporates within the blood clot, balancing the need for adequate hemostasis while preventing development of occlusive thrombosis. TFPI is produced by megakaryocytes but is not expressed on the platelet surface. Activation of platelets with thrombin receptor activation peptide does not cause release or surface expression of TFPI, demonstrating that TFPI is not stored within platelet α granules. TFPI is expressed on the platelet surface following dual-agonist activation with convulxin plus thrombin to produce coated platelets. In association with its expression on the surface of coated platelets TFPI is also released in microvesicles or as a soluble protein.

Description: Following cord blood (CB) transplant and bone marrow (BM) protracted thrombocytopenia remains a serious clinical problem. Platelet production following transplant depends on the availability of adequate numbers of cytokine responsive stem and megakaryocyte progenitor cells (MK-p). Thrombopoietin (TPO), had no clinical impact on thrombopoiesis when given to patients post BMT due to the paucity of MK-p in the grafts. If expanded, Mk-p would supply the appropriate target cells to maximize the effect of TPO and provide efficient earlier platelet engraftment. We propose a novel strategy to facilitate thrombopoiesis, by expanding MK-p from CB mononuclear cells (MNC) prior to transplantation in short term cultures. While CB CD34+ cells can be expanded by several reported methods, isolation of CD34+ cells from the fresh CB is not practical due to the limited number of stem and progenitor cells in the CB units. Additionally, MK expansion from purified stem cells requires long culture periods which are inappropriate for transplantation. We aimed to improved techniques for enrichment and ex-vivo expansion of MK-p and hematopoietic stem cells, from small aliquots of whole CB, using 7–10 days cultures and new growth conditions. CB progenitors were enriched by separation of MNC from RBC on gelatin followed by centrifugation on ficoll, as we previously reported (1). MNC were expanded on fibronectin (FN) coated dishes in the presence of autologous plasma with various new cytokine combinations. These included r-hu-TPO (10 ng/ml), b- FGF (10 ng/ml), r-hu-SCF (50 ng/ml) and ARP a peptide derived from the stress variant of acetylcholinesterase (AChE-R) recently discovered to have potent hematopoietic stem cell and MK growth factor activity (2). The cell populations, MK and MK-p were characterized by high resolution flow cytometry on day 0 and 10 of culture using SSC, CD41 and CD34. True MK expansion was assessed by appropriate gating out of granulocyte and monocytes, which acquire CD41+ adherent platelets in culture. FN alone, without any other growth supplement increased the viability of cells in culture and expansion of MK-p (CD41high, SSClow and FSClow) by 2.8±1.1 (P 〈 0.05) fold. The combination of FN with TPO enhanced MK-p number by 4.8±2.7 and the addition of either SCF or b-FGF or ARP further stimulated the expansion of MK-p all producing about a 6 fold increase (P 〈 0.05). Further analysis was performed on the maturing MKs which were characterized as CD41high, CD45low/negative, CD34negative. Increased Mk ploidy was found when either b-FGF or ARP were added to cultures containing TPO, grown on FN coated plates. Significant MK maturation, as measured by GPIIb/IIIa expression using real time quantitative PCR, was also found. The combination of FN and TPO increased the MK colony forming progenitors in culture by 9 fold and up to 35 fold when other supplements were added. We demonstrate that short term expansion of enriched MK-p from a small fraction of the CB unit is feasible and easy to perform and can comply with GTP regulations. This approach may lead to the development of more effective cell therapy modalities to facilitate platelet production and decrease the time of thrombocytopenia in severely myelosuppressed patients during the extended nadir before platelet engraftment.

Description: The antiphospholipid syndrome (APS) is an acquired thrombophilia, characterized by the occurrence of venous and arterial events. This article examines the laboratory and key clinical aspects of APS. Particular focus is given to anti–beta 2-glycoprotein I (β2GPI) antibodies in view of their recent inclusion in the APS classification criteria. The clinical utility of using the β2GPI enzyme-linked immunosorbent assay, in conjunction with the established lupus anticoagulant assays and cardiolipin enzyme-linked immunosorbent assay, for diagnosing and risk stratifying patients suspected of having APS is discussed. The relative importance of the various assays in diagnosing obstetric APS (early and late gestation miscarriages) is explored. The implications of recent epidemiologic findings for possibly understanding the underlying pathophysiologic mechanisms of obstetric APS are highlighted. Insights into which patients with obstetric APS may be at most risk of thrombotic complications are presented.

Description: Eradication of minimal residual disease (MRD) during the first months of treatment for patients (pts) with ALL is associated with improved disease-free survival (DFS). We hypothesized that Alemtuzumab, a humanized monoclonal antibody directed against CD52, might be an effective, novel agent for eradication of MRD in ALL based on data demonstrating strong CD52 expression in other lymphoid malignancies and in several ALL cell lines, and from case reports of clinical activity in advanced ALL. In CALGB 10102, to define the percentage of CD52+ cases and to demonstrate feasibility, we tested dose escalation of Alemtuzumab in sequential cohorts to a target dose of 30 mg administered sc 3X/week for 4 weeks (12 doses) during post-remission therapy. Pts are eligible to receive Alemtuzumab if lymphoblast CD52 expression at diagnosis is ≥ 10% as determined in a CALGB reference laboratory. The 10102 therapy is composed of monthly treatment modules outlined below: Treatment module sequence is: A,B,C, D, A, B, C followed by maintenance therapy for a total of 2 years. Antimicrobial prophylaxis for cytomegalovirus (CMV) (e.g. acyclovir 800 mg qid) and pneumocystis carinii is mandated. Weekly quantitative monitoring for CMV viremia is performed. 150 pts with untreated ALL have enrolled: Median age is 48 yrs. 124 (83%) pts have precursor-B; 19(13%) have precursor T-ALL and 7 (4%) have biphenotypic or bilineal ALL. Of 139 evaluable pts, 95 (68%) had CD52 ≥ 10%. By immunophenotype, 72% of precursor B and 61% of precursor T pts were eligible to receive Alemtuzumab. Phase I dose escalation was recently completed. Dose limiting toxicity (DLT) for Phase I was defined as the inability to proceed with protocol treatment within 6 weeks of the last dose of Alemtuzumab. Non-heme toxicities have been mild and sc Alemtuzumab administration was well tolerated. Hematologic and infectious toxicities are summarized below: Myelosuppression was transient and use of G-CSF was permitted during Module D. 2 pts were treated for CMV viremia due to rising CMV titers in 2 sequential assays. 6 other pts had transient CMV elevations during or immediately following completion of Alemtuzumab that did not require treatment. 22/24 phase I pts received all 12 doses of Alemtuzumab. There were 2 DLTs reported: 1 pt in cohort 2 due to CMV viremia requiring gancyclovir following completion of Alemtuzumab; and 1 pt in cohort 3 due to ANC 〈 1500 six weeks after Alemtuzumab (pt was not given G-CSF). Based on these Phase I data, the targeted dose of 30 mg Alemtuzumab was recommended for further study in the ongoing Phase II study. In summary, we report for the first time that CD52 is expressed in the majority of ALL cases and demonstrate the feasibility of employing Alemtuzumab in front-line therapy. Ongoing accrual to the phase II study will evaluate the efficacy of Alemtuzumab in eradication of MRD in adult ALL. Module A Module B Module C Module D (Alemtuzumab) Maintenance Cytoxan Cytoxan Methotrexate (IV, PO, IT) 10 mg* cohort 1 Vincristine Daunorubicin Cytarabine Vincristine 20 mg* cohort 2 Dexamethasone Vincristine Vincrisitne 6-MP 30 mg* cohort 3 6-MP Dexamethasone L-asparaginase *Phase I dose escalation Methotrexate L-asparaginase IT-Methotrexate Alemtuzumab cohorts N Myelosuppression (grades 3 or 4) Lymphopenia CMV viremia 10 mg 6 2 1 2 20 mg 10 1 1 4 30 mg 8 1 0 2

Description: To study B-cell development from bone marrow (BM), we generated recombination-activating gene 1 (Rag1)–targeted mice lacking mature lymphocytes. B-cell development can be induced in such mice by B cell–specific restoration of a functional Rag1 transcription unit. Follicular and marginal zone B cells populated the spleen when Rag1 expression was permitted. Notably, the peritoneal cavity was dominated by bona fide B-1a cells, as judged by surface markers and functional properties. These BM-derived B-1a cells exhibited a polyclonal VDJ repertoire with substantial N nucleotide insertions. Nevertheless, physiologic frequencies of phosphatidylcholine-specific B cells were detected. Importantly, the BM of young and 5-month-old mice was indistinguishable with regard to the potential to generate B-1a cells.

Description: Autologous stem cell transplantation (ASCT) remains the standard consolidation therapy for patients with multiple myeloma (MM) and chemosensitive relapsed lymphoma (r-Ly). Peripheral blood as a source of stem cells (PBSC) has largely replaced marrow and has the advantage of improved engraftment rates. PBSC are routinely collected following administration of chemotherapy in combination with GCSF. However, the resultant pancytopenia poses a significant risk to patients and additional chemotherapy prior to ASCT may lead to increased end organ damage potentially precluding future therapies (including ASCT). Novel agents can achieve PBSC mobilisation without the use of cytotoxics. In the advent of such drugs, we reviewed the efficacy of, and complications experienced by patients during PBSC mobilisation. We also analysed the cost implications of adverse events. Of 151 consecutive attempts, 13.2% of patients failed to reach our criteria in order to attempt pheresis (1 × 104 CD34 cells/ml). Of those achieving target and undergoing pheresis, 6% did not achieve an adequate cell dose for future ASCT (2 × 106CD34+cells/kg) giving an overall failure rate of 19.2%. Furthermore 17.9% failed to harvest our ideal of 4 × 106/kg (permitting 〉1 ASCT procedure). Factors contributing to failure in achieving target CD34+ve PB count on univariate analysis were; 〉2 lines of previous chemotherapy and occurrence of neutropenic sepsis (NS (p=0.002, and 0.005 respectively). These factors remained significant on multivariate analysis (RR: 4.4 and 6.2). These same factors also affected CD34+ cell yield on both univariate and multivariate analysis (RR: 3.3 and 4.6). No differences were seen between MM and r-Ly. Overall, the complication rate was 34.4%, with 24.1% of patients suffering NS requiring admission. The mortality rate was 1.3% (NS and intra-cranial bleed). Of those developing NS, only 52% eventually harvested sufficient cells, but with a median delay of 3 days. The median cost of PBSC collection was $17,381.46 ($1,978.97–$39,355.73). NS significantly increased the cost of mobilisation at a median cost of $25,532.95 vs $16,4921) (p=

Description: Historically, graft-versus-host disease (GVHD) beyond 100 days after hematopoietic cell transplantation (HCT) was called chronic GVHD, even if the clinical manifestations were indistinguishable from acute GVHD. In 2005, the National Institutes of Health (NIH) sponsored a consensus conference that proposed new criteria for diagnosis and classification of chronic GVHD for clinical trials. According to the consensus criteria, clinical manifestations rather than time after transplantation should be used in clinical trials to distinguish chronic GVHD from late acute GVHD, which includes persistent, recurrent, or late-onset acute GVHD. We evaluated major outcomes according to the presence or absence of NIH criteria for chronic GVHD in a retrospective study of 740 patients diagnosed with historically defined chronic GVHD after allogeneic HCT between 1994 and 2000. The presence or absence of NIH criteria for chronic GVHD showed no statistically significant association with survival, risks of nonrelapse mortality or recurrent malignancy, or duration of systemic treatment. Antecedent late acute GVHD was associated with an increased risk of nonrelapse mortality and prolonged treatment among patients with NIH chronic GVHD. Our results support the consensus recommendation that, with appropriate stratification, clinical trials can include patients with late acute GVHD as well as those with NIH chronic GVHD.

Description: Chronic immune activation is a major cause for progressive immunodeficiency in human immunodeficiency virus type-1 (HIV) infection. The underlying trigger, however, remains largely unknown. HIV single-stranded RNA is a potent immune activator by triggering Toll-like receptor (TLR) 7/8. Thus, we hypothesized that sustained TLR7 triggering induces chronic immune activation and thereby contributes to progressive immunodeficiency. We used the synthetic compound R848 or a mixture of uridine-rich HIV single-stranded (ss) RNA oligonucleotides—both are potent TLR7/8 agonists—to explore the effects of sustained TLR7 triggering on the murine lymphoid system. Sustained TLR7 triggering induced an immunopathology reminiscent of progressive lymphoid destruction in HIV disease; we observed lymphopenia, elevated proinflammatory cytokines, splenomegaly, contracted lymphoid subsets, and lymphoid microarchitecture alteration with reduced marginal zone B-lymphocytes. Upon exposure to inactivated vesiculo-stomatitis virus, antibody production was abolished, although splenic lymphocytes were activated and total IgG was elevated. Our data imply that HIV itself may directly contribute to immune activation and dysfunction by stimulating TLR7. Thus, manipulation of TLR7 signaling may be a potential strategy to reduce chronic hyper-immune activation and, thereby, disease progression in HIV infection.

Description: Polymorphisms in folate pathway genes may influence the susceptibility to acute lymphoblastic leukemia (ALL). DNA was isolated from 245 pediatric ALL patients (cases) and from 500 blood bank donors (controls). Polymorphisms in methylene-tetrahydrofolate reductase (MTHFR 677C〉T, 1298A〉C), methionine synthase (MTR 2756A〉G), methionine synthase reductase (MTRR 66A〉G), methylenetetrahydrofolate dehydrogenase (MTHFD1 1958G〉A), nicotinamide N-methyltransferase (NNMT IVS −151C〉T), serine hydroxymethyl transferase (SHMT1 1420C〉T), thymidylate synthase (TS 2R3R), and the reduced folate carrier (RFC1 80G〉A) were detected. In ALL patients, an increased occurrence was observed of the RFC1 80AA variant (odds ratio [OR] = 2.1; 95% confidence interval [CI] = 1.3-3.2; P = .002) and the RFC1 80A allele (OR = 1.5; 95% CI, 1.1-2.1; P = .02). Likewise, the NNMT IVS −151TT genotype showed a 2.2-fold increased ALL risk (OR = 2.2; 95% CI, 1.1-4.6; P = .04). A 1.4-fold reduction in ALL risk was observed for (heterozygous or homozygous) carriers of the TS 2R allele and the MTHFR 677T allele (OR = 0.7; 95% CI, 0.5-1.0; P 〈 .05). Furthermore, interactions between NNMT and MTHFR 677C〉T and RFC1 were observed. NNMT IVS −151CC/MTHFR 677CT + TT patients exhibited a 2-fold reduction in ALL risk whereas RFC1 80AA/NNMT IVS −151CT + TT subjects had a 4.2-fold increase in ALL risk (P = .001). For the first time, we associate the RFC1 80G〉A and NNMT IVS −151C〉T variants to an increased ALL susceptibility.

Description: Introduction Several components of the haemostatic system are altered in sickle cell anaemia(SCA). The sum of these alterations is manifested as a state of hypercoagulability. Many therapeutic approaches including anticoagulants has been tried in managing the acute painful crisis of SCA along with the analgesics. Aim This trial aimed at assessing the efficacy and safety of low molecular weight heparin Tinzaparine (innohep®) as an adjuvant therapy in the management of acute painful vaso-occlusive crisis. Material and Methods This two arm pilot, randomised multi-centre controlled prospective trial has incorporated 253 patients admitted through emergency in acute painful crisis, with no other complications of SCA. Subjects were consecutively randomized to the study or control group. In the study group 127 patients (mean age 22,83 years) received tinzaparine 175 i.u, s.c once daily along with analgesics, while in the control group 126 patients (mean age 21,64 years) received placebo and the same analgesics. Subjects were followed for improvement using the numerical pain scale (NMS), assessing the number of days in which the patient experienced the severest degree of pain on the NMS, the hospitalization period, the duration of painful crisis, and the rate at which the pain intensity declined over time. The maximal treatment period was seven days. The complications encountered are treated and estimated in both groups. The results were analysed using “SSPS-V10” statistical tests Results The results displayed in the table.1 showed statistically significant reduction in the duration of morbidity in the study group. The drop in the pain intensity is sharper, and the complications experienced in the study group were two events of minor bleeding treated conservatively. Patient Control No. of days with severest pain score on the NMS (Days) 1,28 1,74 Duration of painful crisis(Days) 2,57 4,35 Total duration of hospitalization(Days) 7.08 12,06 Conclusion The results indicate a favourable outcome in the study group compared to the control group. The use of tinzaparine in the acute painful crisis of SCA as an adjuvant to the strong analgesics is recommended due to its proven efficacy and safety in shortening the period of the agonizing pain at presentation, the period of painful crisis and the hospital stay.

Description: Natural interferon (IFN)-producing cells are the primary cell type responsible for production of type I IFN in response to viruses. Herein we report the identification of the first molecular marker of mouse natural interferon-producing cells (IPCs), a novel member of the sialic acid-binding immunoglobulin (Ig)-like lectin (Siglec) family termed Siglec-H. Siglec-H is expressed exclusively on IPCs and is unique among Siglec proteins in that it associates with the adaptor protein DAP12. Moreover, we show that DAP12 modulates the type I IFN response of IPCs to a Toll-like receptor 9 (TLR9) agonist. This observation explains our previous finding that stimulation of IPCs with 440c, a Siglec-H-specific antibody, reduces IPC secretion of type I IFN. Moreover, it supports a model in which engagement of DNAX-activation protein 12 (DAP12)-associated receptors with antibodies or low avidity endogenous ligands interferes with TLR-mediated cellular activation. (Blood. 2006;107:2474-2476)

Description: Resolvin E1 (RvE1) is an omega-3 eicosapentaenoic acid (EPA)–derived lipid mediator generated during resolution of inflammation and in human vasculature via leukocyte-endothelial cell interactions. RvE1 possesses anti-inflammatory and proresolving actions. Here, we report that RvE1 in human whole blood rapidly regulates leukocyte expression of adhesion molecules. RvE1 in the 10- to 100-nM range stimulated L-selectin shedding, while reducing CD18 expression in both neutrophils and monocytes. When added to whole blood, RvE1 did not stimulate reactive oxygen species by either neutrophils or monocytes, nor did it directly stimulate cytokine/chemokine production in heparinized blood. Intravital microscopy (IVM) demonstrated that RvE1 rapidly reduced leukocyte rolling (∼ 40%) in venules of mice. In human platelet-rich plasma (PRP), RvE1 selectively blocked both ADP-stimulated and thromboxane receptor agonist U46619-stimulated platelet aggregation in a concentration-dependent manner. In contrast, Δ6,14-trans-RvE1 isomer was inactive. RvE1 did not block collagen-stimulated aggregation, and regulation of ADP-induced platelet aggregation was not further enhanced with aspirin treatment. These results indicate RvE1 is a potent modulator of leukocytes as well as selective platelet responses in blood and PRP, respectively. Moreover, the results demonstrate novel agonist-specific antiplatelet actions of RvE1 that are potent and may underlie some of the beneficial actions of EPA in humans.

Description: Central venous catheters (CVCs) are widely used in patients with hemato-oncological disease for indications such as administration of chemotherapy, parenteral nutrition, blood products and monitoring of hemodynamics. CVCs are a major source of hospital-acquired infection. The National Nosocomial Infections Surveillance System reported a rate of catheter-related bloodstream infection (CRBI) of five per 1000 central catheter-days. This study was a randomized trial in which patients with nontunneled catheters were randomly assigned to heparin-coated (7 French, polyurethane, double lumen; Arrow®, USA) or chlorhexidine and silver sulfadiazine impregnated CVCs (7 French, polyurethane, double lumen; Arrow®, USA). All CVCs were placed in the subclavian vein in the operating room. CRBI was defined according to Infectious Disease Society of America guidelines. The principal investigator determined whether infections were catheter related and had no knowledge of “the assigned arm” at the time of adjudication of the reference standard definition. Before catheter insertion, laboratory prothrombotic markers included factor V Leiden, the prothrombin gene Gly20210A mutation, plasma antithrombin levels, and protein C and S activity. In our study, all patients were systematically examined by ultrasonography just before, or less than 24 hours after, catheter removal and in case of clinical signs of thrombosis. Two radiologists performed the ultrasonography and were unaware of the allocation of the patients. Two hundred and twenty patients were randomly assigned. Eight patients were excluded after assignment. Ultimately, 212 patients were analyzed [median age: 28 years (7–60); 97 female and 115 male]. CRBI occurred in 6.7% (7/104) of those in the heparin-coated group (2.7 events per 1000 days) and in 4.6% (5/108) in the chlorhexidine and silver sulfadiazine group (2 events per 1000 days) (P=0.5). The microorganisms involved in CRBIs were coagulase-negative Staphylococcus (five cases in the heparin group and 3 cases in the antiseptic group), Staphylococcus aureus (one case in the heparin group), Candida parapsilosis (one case in the antiseptic group), Pseudomonas aeruginosa (one case in the heparin group and one case in the antiseptic group). We observed a CVC-related thrombosis in 11 patients (5.2%; 5 in the heparin group and 6 in the antiseptic group P=0.8). Catheter-related thrombosis and CRBI coincided in two patients and were not significantly correlated (P=0.6). Four (1.9%) and three (1.4%) patients had evidence of protein C and protein S deficiency, respectively. Only one patient had an antithrombin deficiency (0.5%). In total, 9 patients (4.2%) were heterozygous for the factor V Leiden mutation. Thrombosis was diagnosed in three out of 17 patients (17.6%) with a inherited prothrombotic abnormality compared to 8 out of 195 patients (4.1%) who did not have a thrombophilic marker (relative risk 4.3 CI 95% 1.2–14.7). Six and five patients experienced severe bleeding in the heparin and antiseptic groups, respectively. We did not observe heparin-induced thrombocytopenia and anaphylaxis to chlorhexidine was not reported. To our knowledge, this is the first randomized study comparing in haematological patients heparin-coated with antiseptic impregnated CVCs. Furthermore, our results suggest that inherited prothrombotic abnormalities contribute substantially to CVC-related thrombosis in hemato-oncological patients. Presently, the best options for reducing CRBI are heparin-coated and antibiotic-impregnated CVCs. A large, well designed randomized controlled trial is required to determine which of these is most effective.

Description: Background: Platelet transfusion practice in neonates is not evidence-based and there is a lack of data relating transfusion to clinical outcome. To inform the design of clinical trials, we conducted a prospective multicentre observational study of platelet transfusion in thombocytopenic neonates to describe: transfusion practice, including reason for transfusion; clinically-related outcomes, including minor and major bleeding and mortality. Methods: Neonates with platelets

Description: Tumor growth is associated with aberrant myelopoiesis, including the accumulation of CD11b+Gr-1+ myeloid-derived suppressor cells (MDSCs) that have the potential to promote tumor growth. However, the identity, growth, and migration of tumor-associated MDSCs remain undefined. We demonstrate herein that MDSCs at tumor site were composed primarily of bone marrow-derived CD11b+Gr-1hiLy-6Cint neutrophils and CD11b+Gr-1int/dullLy-6Chi macrophages. Unexpectedly, in vivo bromodeoxyuridine (BrdU) labeling and parabiosis experiments revealed that tumor-infiltrating macrophages were replenished more rapidly than neutrophils. CCR2 deficiency caused striking conversion of infiltrating cellular dominance from macrophages to neutrophils in the tumor with the excessive production of CXCR2 ligands and granulocyte-colony stimulating factor in the tumor without affecting tumor growth. Overall, our data established the identity and dynamics of MDSCs in a tumor-bearing host mediated by chemokines and elucidated unexpected effects of the paucity of macrophages on tumor development.

Description: Stem cell gene therapy has long been limited by low gene transfer efficiency to hematopoietic stem cells. Recent years have witnessed clinical success in select diseases such as X-linked severe combined immunodeficiency (SCID) and ADA deficiency. Arguably, the single most important factor responsible for the increased efficacy of these recent protocols is the fact that the genetic correction provided a selective in vivo survival advantage. Since, for most diseases, there will be no selective advantage of gene-corrected cells, there has been a significant effort to arm vectors with a survival advantage. Two-gene vectors can be used to introduce the therapeutic gene and a selectable marker gene. Efficient in vivo selection strategies have been demonstrated in clinically relevant large-animal models. Mutant forms of the DNA repair-enzyme methylguanine methyltransferase in particular have allowed for efficient in vivo selection and have achieved sustained marking with virtually 100% gene-modified cells in large animals, and with clinically acceptable toxicity. Translation of these strategies to the clinical setting is imminent. Here, we review how in vivo selection strategies can be used to make stem cell gene therapy applicable to the treatment of a wider scope of genetic diseases and patients.

Description: Various human disorders are associated with misdistribution of iron within or across cells. Friedreich ataxia (FRDA), a deficiency in the mitochondrial iron-chaperone frataxin, results in defective use of iron and its misdistribution between mitochondria and cytosol. We assessed the possibility of functionally correcting the cellular properties affected by frataxin deficiency with a siderophore capable of relocating iron and facilitating its metabolic use. Adding the chelator deferiprone at clinical concentrations to inducibly frataxin-deficient HEK-293 cells resulted in chelation of mitochondrial labile iron involved in oxidative stress and in reactivation of iron-depleted aconitase. These led to (1) restoration of impaired mitochondrial membrane and redox potentials, (2) increased adenosine triphosphate production and oxygen consumption, and (3) attenuation of mitochondrial DNA damage and reversal of hypersensitivity to staurosporine-induced apoptosis. Permeant chelators of higher affinity than deferiprone were not as efficient in restoring affected functions. Thus, although iron chelation might protect cells from iron toxicity, rendering the chelated iron bioavailable might underlie the capacity of deferiprone to restore cell functions affected by frataxin deficiency, as also observed in FRDA patients. The siderophore-like properties of deferiprone provide a rational basis for treating diseases of iron misdistribution, such as FRDA, anemia of chronic disease, and X-linked sideroblastic anemia with ataxia.

Description: Rapid loss of blood, in the operating room or trauma, necessitates a need for hastening coagulation Attempts to hasten coagulation include electrocautery based on thermal plasma discharges. Although there have been other effective attempts to prevent further loss of blood via coagulation, tissue damage and dessication can occur as a result of the high temperatures 2. Our group has developed a method to initiate rapid coagulation with dielectric plasma discharge (cold). Initial experiments were performed using fresh blood from volunteers to compare time for coagulation of whole blood exposed to plasma, one minute versus 10 minutes. We tried same experiments on cut cadaver organs such as spleen and placenta which showed evidence of rapid coagulation compared to control without evidence of tissue damage. Our research team has developed a novel method using non-thermal dielectric barrier discharge plasma (DBD plasma) to coagulate blood and sterilize tissues without causing thermal damage. This treatment would be safe to patients because no exposed electrodes are involved and high frequency current (under 10 KHz) is kept below mili-ampere. Our experiments have shown that such plasma treatment hastens blood coagulation and causes simultaneous wound sterilization via a large concentration of chemically active species in plasma that are ions, radicals (O, OH, N) and electronically-excited atoms and molecules. A kinetic model of blood coagulation under influence of DBD plasma was constructed. The model assumes contact flux of positive ions from DBD plasma into the surface of the blood being treated. Once at the surface, these ions recombine, leading to formation of aqueous Hydrogen ions which catalyze the release of Calcium ions into the blood. The addition of Calcium ions to blood speeds up the coagulation process proportionally to the amount of ions added. The model demonstrates thrombin formation in the presence of DBD plasma peaking and occurring within significantly less time compared to thrombin formation without DBD plasma3. Such medically relevant demonstrations and mathematical explanations have allowed us to develop a portable device that may prove useful in situations where control of bleeding is crucial. In addition, because of the potential for simultaneous sterilization, this device may also help to decrease infections. This pioneering technology will find applicability in many clinical situations: sterilization of human tissue surfaces prior to surgery and sterilization of catheters, a well-known cause of morbidity in hospitals.

Description: Factors regulating which patients become alloimmunized to red blood cell (RBC) antigens are poorly understood. Using a murine model of transfusion, we recently reported that viral-like inflammation with polyinosinic polycytidylic acid [poly (I:C)] significantly enhances RBC alloimmunization. Herein, we tested the hypothesis that poly (I:C) exerts this effect, at least in part, at the level of antigen-presenting cells (APCs). Using a novel in vivo method, we report that in the noninflamed state, most transfused RBCs were consumed by splenic macrophages, with only trace consumption by splenic dendritic cells (DCs). To a lesser extent, RBCs were also consumed by APCs in the liver. However, unlike soluble antigens, no RBCs were consumed by APCs in the lymph nodes. Inflammation with poly (I:C) induced significant consumption of transfused RBCs by splenic DCs, with a concomitant increase in costimulatory molecule expression. Moreover, this resulted in increased proliferation of CD4+ T cells specific for the mHEL RBC alloantigen. Finally, splenectomy abrogated the enhancing effects of poly (I:C) on RBC alloimmunization. Together, these data provide additional insight into the nature of transfused RBCs as an immunogen and provide a mechanism by which viral-like inflammation enhances alloimmunization to transfused RBCs.

Description: Hematopoietic stem cells (HSCs) arise, self-renew, or give rise to all hematopoietic lineages through the effects of transcription factors activated by signaling cascades. Lyl-1 encodes a transcription factor containing a basic helix-hoop-helix (bHLH) motif closely related to scl/tal, which controls numerous decisions in embryonic and adult hematopoiesis. We report here that Lyl-1 null mice are viable and display normal blood cell counts, except for a reduced number of B cells resulting from a partial block after the pro-B stage. Nevertheless, the deletion of Lyl-1 results in a diminution in the frequency of immature progenitors (Lin–, CD34–, sca-1+, c-kit+ [LSK], and LSK-side population [LSK-SP]) and in S12 colony-forming unit (CFU-S12) and long-term culture-initiating cell (LTC-IC) content in embryonic day 14 fetal liver (E14 FL) and adult bone marrow (BM). More important, Lyl-1–/– E14 FL cells and BM are severely impaired in their competitive reconstituting abilities, especially with respect to B and T lineage reconstitution. Thus, ablation of Lyl-1 quantitatively and functionally affects HSCs, a cell population that transcribes Lyl-1 more actively than their differentiated progenies. Our results demonstrate for the first time that Lyl-1 functions are important for HSC properties and B-cell differentiation and that they are largely distinct from scl functions.

Description: The Stroke Prevention Trial in Sickle Cell Anemia (STOP) was a randomized trial to evaluate whether chronic transfusion could prevent initial stroke in children with sickle-cell anemia at high risk as determined by transcranial Doppler (TCD). The trial demonstrated a large benefit of transfusion and was halted early. After termination of the trial, patients participated in a posttrial follow-up study. More patients in the transfusion group (70%) elected transfusion for primary stroke prevention compared with those on standard care (45%). Six patients with persistently abnormal TCD results developed stroke. A minority with initially abnormal TCD results remained stroke-free without transfusion. Except for lower baseline and follow-up TCD velocities compared with those with stroke, no predictive features of this apparent lower-risk subgroup could be determined. TCD results at last testing in 108 patients that did not have stroke were: normal (44.4%), conditional (26.9%), abnormal (22.2%), and inadequate (6.5%). Patients on transfusion were more likely to have normal TCD results. Transfusion resulted in iron overload and alloimmunization, but no infection. The study provides new information on acceptance rates and long-term effects of transfusion. Persistent TCD elevation signals ongoing stroke risk. Reduction in TCD results over time without transfusion is observed in some patients and requires further study.

Description: Recently, inhibitory cytokine pathways for leukocyte chemoattraction and activation have been identified, but there is little insight into the operational mechanisms except for models that rely on simple receptor antagonism. We have previously identified the existence of a murine eosinophil inhibitory pathway mediated by the CXC chemokine ligand 9 (CXCL9, Mig [monokine induced by interferon-γ]) that impressively blocks eosinophil chemoattraction and function, but the mechanism has remained elusive. We now demonstrate that Mig's inhibitory action extends beyond receptor antagonism alone. Notably, in addition to inhibiting eotaxin-induced filamentous actin (F-actin) formation and chemoattraction, Mig potently blocks platelet activating factor (PAF)– and leukotriene B4 (LTB4)–induced responses. Remarkably, Mig-treated eosinophils display an abnormal F-actin assembly in the absence of agonist stimulation. Additionally, Mig pretreatment inhibits eotaxin-induced activation of the Rho–guanosine triphosphatase (GTPase) Rac, and Rac2-deficient eosinophils demonstrate an impaired transmigration and actin polymerization response to eotaxin stimulation. Furthermore, Mig was unable to inhibit eotaxin-induced responses in Rac2-deficient eosinophils. Finally, using CCR3 gene–targeted cells, Mig's inhibitory activity is demonstrated to be mediated by CC chemokine receptor 3 (CCR3). Thus, by altering agonist-induced signaling and abrogating cytoskeletal reorganization by a Rac2-dependent mechanism, Mig markedly inhibits eosinophil responses to diverse stimuli. These results establish evidence that distinct chemokines can use CCR3 to induce opposing signals in eosinophils.

Description: The JAK2V617F somatic point mutation has been described in patients with myeloproliferative disorders (MPDs). Despite this progress, it remains unknown how a single JAK2 mutation causes 3 different MPD phenotypes, polycythemia vera (PV), essential thrombocythemia, and primitive myelofibrosis (PMF). Using an in vivo xenotransplantation assay in nonobese diabetic-severe combined immunodeficient (NOD/SCID) mice, we tested whether disease heterogeneity was associated with quantitative or qualitative differences in the hematopoietic stem cell (HSC) compartment. We show that the HSC compartment of PV and PMF patients contains JAK2V617F-positive long-term, multipotent, and self-renewing cells. However, the proportion of JAK2V617F and JAK2 wild-type SCID repopulating cells was dramatically different in these diseases, without major modifications of the self-renewal and proliferation capacities for JAK2V617F SCID repopulating cells. These experiments provide new insights into the pathogenesis of JAK2V617F MPD and demonstrate that a JAK2 inhibitor needs to target the HSC compartment for optimal disease control in classical MPD.

Description: Recent studies by our laboratory have demonstrated unequivocally that factor V is endocytosed by megakaryocytes from plasma to form the platelet-derived factor V pool. In the current study, we have determined the time-dependent acquisition of factor V by platelets in a 67 year old factor V-deficient patient, previously shown to be completely devoid of plasma- and platelet-derived factor V. The patient now receives weekly tranfusions of two units of FFP to prevent gastrointestinal bleeding. Plasma and platelet lysate samples were prepared from fresh, whole blood drawn prior to (0 hrs), and following (2, 6, 24, 96, 168 hrs) patient transfusion. A factor V radioimmunoassay (RIA), which can detect factor V concentrations as low as 0.075 μg/mL, a standard factor V clotting-based activity assay, and/or western blotting analyses, which utilize a mixture of anti-human factor V light chain and heavy chain mAbs, were used to evaluate the appearance, and subsequent disappearance, of factor V in these two blood compartments. Prior to transfusion (t = 0 hr), the patient’s plasma-derived factor V could not be detected by any of the three factor V assays. The patient’s plasma-derived factor V level peaked immediately following transfusion (t = 2 hr) reaching a concentration of 1.3 +/− 0.08 μg/mL as measured by RIA, and declined until it reached an undetectable level at 96 hrs post transfusion. These data were confirmed by the results of both the clotting-based assays and western blotting analyses. As the patient’s platelet-derived factor V levels were below the sensitivity of both the RIA and clotting assay, they were analyzed by western blotting. Such analyses confirmed that subsequent to its endocytosis, the patient’s platelet-derived factor V is stored in a partially protelytically activated form similar to that of a control individual. Due to the partially proteolytically activated state of the platelet-derived cofactor, platelet lysates treated with thrombin to activate the factor V to factor Va were used for quantative western blotting. Interestingly, and perhaps consistent with the patient’s receipt of weekly FFP transfusions, factor V/Va could still be detected in platelets immediately prior to transfusion. Subsequent to transfusion and in marked contrast to changes in the plasma-derived cofactor pool, a significant increase in the patient’s platelet-derived factor V/Va level was not observed until 24 hrs post transfusion. These data are consistent with previous studies demonstrating that platelets do not endocytose factor V. Although the concentration of the platelet-derived factor V/Va pool decreased over the subsequent 6 days, antigen remained detectable even though the plasma-derived pool had been depleted 3 days earlier. These combined observations indicate that, subsequent to FFP administration, the patient’s megakaryocytes acquire and proteolytically process plasma-derived factor V normally. Furthermore, the consistent presence of factor V/Va within the patient’s platelets is in all likelihood preventing gastrointestinal bleeding in this individual, which supports the concept that platelet-derived factor V represents the hemostatically relevant factor V pool.

Description: The RECORD program comprised four pivotal phase III trials comparing the oral direct Factor Xa inhibitor, rivaroxaban, with subcutaneous enoxaparin for the prevention of venous thromboembolism (VTE) after total hip and knee replacement (THR and TKR). A total of 12,729 patients were randomized to receive rivaroxaban 10 mg once daily (od) starting 6–8 hours after surgery, or enoxaparin 40 mg od (RECORD1–3) starting the evening before surgery, or 30 mg every 12 hours (RECORD4) starting 12–24 hours after surgery. In RECORD1, patients undergoing THR received extended prophylaxis for 31–39 days. In RECORD2, patients undergoing THR received rivaroxaban for 31–39 days, or enoxaparin for 12±2 days followed by placebo up to 35 days. Patients undergoing TKR in RECORD3 and 4 received prophylaxis for 12±2 days. In all four trials the rivaroxaban regimens showed superior efficacy to the enoxaparin regimens with no significant increase in bleeding. The RECORD1–4 pooled analysis showed that rivaroxaban was significantly superior to enoxaparin for the primary endpoint, symptomatic VTE and all-cause mortality (0.8% vs 1.6%, respectively; p70–90, 〉90kg), gender, or renal function (CrCl 〉80, 50–80, 80 and 30 ml/min CrCl) groups studied. Similar trends were seen in the smaller subgroups of body weight extremes (〉110 kg subgroup - total VTE: 5/100 [5.0%] vs 8/119 [6.7%], respectively; ≤50 kg subgroup - any bleeding: 12/147 [8.2%] vs 8/162 [4.9%], respectively). These results suggest that age, body weight, gender and renal function (〉30 ml/min CrCl) have no clinically relevant effect on the efficacy or safety of rivaroxaban as thrombroprophylaxis following major orthopedic surgery. Subgroup Total VTE Odds ratio (rivaroxaban vs enoxaparin regimens) (95% CI Major VTE Odds ratio (rivaroxaban vs enoxaparin regimens) (95% CI) Any major or non-major bleeding Hazard ratio (rivaroxaban vs enoxaparin regimens) (95% CI) *Because of study exclusion criteria, few patients had CrCl 70–90kg 0.45 (0.34–0.59) 0.21 (0.11–0.39) 0.95 (0.77–1.17) 〉90kg 0.38 (0.25–0.57) 0.32 (0.13–0.69) 1.22 (0.95–1.58) Gender Male 0.35 (0.25–0.48) 0.21 (0.10–0.40) 1.12 (0.93–1.36) Female 0.47 (0.37–0.59) 0.27 (0.16–0.45) 1.06 (0.87–1.28) CrCl (ml/min) 〉80 0.35 (0.27–0.46) 0.22 (0.12–0.38) 1.12 (0.94–1.35) 50–80 0.60 (0.45–0.81) 0.30 (0.15–0.56) 0.99 (0.79–1.24)

Description: Dietary plant polyphenols are known to have antitumor, antiinflammatory, and antioxidant activity and as such may sensitize tumor cells to chemotherapeutic agents. We have evaluated the effects of the green tea polyphenol epigallocatechin gallate (EGCG) alone and in combination with other drugs on human myeloma cells. The compound is currently under investigation in several phase I/II clinical trials including for treatment of patients with early stage chronic lymphocytic leukemia. EGCG inhibited the in vitro growth of human myeloma cell lines in a time and dose-dependent manner. IC50 concentrations were between 12.5 μM and 50 μM as measured in a colorimetric tetrazolium (MTS) based assay and by trypan blue exclusion. Excess amounts of IL-6, bone marrow stromal cells, or overexpression of Mcl-1 and Bcl-xL could not protect from EGCG induced cytotoxicity. Pretreatment of INA-6 cells with EGCG resulted in a dose-dependent inhibition of IL-6 induced STAT3 tyrosine phosphorylation. In accordance with the essential role of STAT3 for INA-6 cell survival, EGCG induced apoptosis as determined by flow cytometry upon 7-amino-actinomycin D/annexin-V staining. In cell lines not dependent on exogenous IL-6, EGCG induced growth inhibition was abolished by pretreating the cells with 200 U/ml catalase, an enzyme which reduces reactive oxygen species (ROS). The combination of EGCG with doxorubicin, dexamethason, or rapamycin did not result in increased growth inhibition. In contrast, growth inhibition by bortezomib was antagonized with EGCG at concentrations that were not inhibitory when used alone (1–10 μM). In conclusion, EGCG exerts its effects on myeloma cells through several mechanisms including inhibition of IL-6 mediated signalling pathways via STAT3 and induction of oxidative stress. Notably, at pharmacologically achievable concentrations, EGCG antagonized bortezomib activity. Thus, the intake of natural polyphenols (high consumption of green tea or taking green tea extracts) may be critical during therapy with bortezomib.

Description: PU.1 (Sfpi1) is an ets family transcription factor required for the proper generation of both myeloid (macrophages and neutrophils) and lymphoid lineages (B and T lymphocytes)(Scott 1994, McKercher 1996). Graded expression of exogenous PU.1 in murine PU.1-deficient fetal liver hematopoietic progenitors demonstrated that increased levels of PU.1 are required to initiate development of macrophages (DeKoter, 2000). We have studied the effects of graded expression of PU.1 on its occupancy in chromatin and on the development of myeloid cells in vitro. We measured changes in gene expression, PU.1 occupancy and histone modifications in PU.1-null hematopoietic progenitor cells stably expressing PU.1 fused to the ligand-binding domain of the estrogen receptor (PU.1-ER) (Walsh 2002). The level of active PU.1-ER was regulated with graded levels of the ER inducer tamoxifen. In vitro, intermediate levels of tamoxifen produced cells with granulocyte characteristics in the suspension cell fraction and macrophage-like characteristics in the attached fraction, whereas high levels of PU.1 produced mostly attached macrophage-like cells. Expression of granulocyte-specific PU.1 target mRNAs including gelatinase B (Mmp9) and myeloperoxidase (Mpo) were observed to be expressed only with intermediate levels of tamoxifen. In contrast, expression of macrophage PU.1 target mRNAs including Cd14, F4/80 and Cd68 mRNAs were observed to be gradually upregulated upon PU.1-ER activation, with the maximum expression at the highest levels of tamoxifen. Thus, the expression levels of PU.1 target genes and phenotypic characteristics of the cells are dependent on PU.1 levels. Interestingly, macrophage-like cells can be produced from granulocytic-like cells by changing tamoxifen levels and vice versa. Chromatin immunoprecipitation analysis revealed specific PU.1 occupancy within regulatory regions of the genes predominantly expressed in macrophages including Cd14 and Cd11b after treatment with high levels of tamoxifen. Specific PU.1 occupancy within regulatory regions of the granulocyte specific genes including MMP9 was observed at intermediate levels of tamoxifen. Suprisingly, chromatin immunoprecipitation analysis revealed specific PU.1 occupancy within regulatory regions of the lymphocytic PU.1 target genes including Interleukin-7 receptor (Il-7r) and RAG1 at intermediate levels of tamoxifen even though expression of these genes was not detected. Accumulation of acetylated K9 and methylated K4 of histone H3 in gene loci of macrophage and granulocytic markers such as Cd14, Cd11b, and Mmp9 correlated with their mRNA expression. However, lymphocyte-specific regulatory regions including that of Il-7r gene were hypoacetylated in H3K9 despite a marked PU.1 recruitment suggesting additional factors may be required for PU.1 mediated transactivation. To identify these molecules we have tested PU.1-dependent transcription factors: Egr2, Nab2, Cebpa and Gfi-1 and found that upon increasing PU.1 levels, expression of Egr2/Nab2 and Gfi-1/Cebpa changed in a reciprocal manner and these changes preceded expression of the lineage specific markers. We are currently testing if PU.1 directly regulates expression of Egr2, Nab2, Cebpa and Gfi-1 during granulocytic/macrophage differentiation.

Description: CD26 (dipeptidyl peptidase IV, DPP IV) is a multifunctional type II cell surface glycoprotein that is widely expressed on T and natural killer cells, as well as on epithelial, endothelial and acinar cells of different tissues; its expression on B cells is very low but it is greatly upregulated following activation. We evaluated, by means of flow cytometry, the expression of CD26 in various types of B-cell lymphoid tumors: Follicular Lymphoma (Fo-Ly, 12 cases), Mantle cell Lymphoma (MCL, 12 cases) Multiple Myeloma (MM, 20 cases), Hairy cell Leukemia (HCL, 12 cases), B-cell Chronic Lymphocytic Leukemia (B-CLL, 112 cases), CD5 negative B-cell Chronic Lymphoproliferative Diseases (CD5neg-B-CLPD, 20 cases) and Diffuse Large cell Lymphoma (DLCL, 12 cases). CD26 expression was absent or low of Fo-Ly and MCL, high on MM and HCL, variable on B-CLL, CD5neg-B-CLPD and DLCL. Fluorescence intensity of positive cells was dim in B-CLL and CD5neg-B-CLPD, heterogeneous in DLCL, and bright in HCL and MM. Interestingly, in CLL patients, CD26 expression was significantly correlated with CD49d and CD38 expressions (p

Description: Due to the lack of large population-based studies, the incidence of polycythemia vera (PV) has not been well documented in the United States. In 2001, PV became reportable to the Surveillance, Epidemiology, and End Results (SEER) program, which consists of high-quality population-based cancer registries supported and sponsored by the National Cancer Institute. In the present analysis, we accessed the SEER data to estimate the incidence of PV in the United States during 2001 – 2003. Since the addition of PV to SEER reporting is fairly recent, and the diagnosis of PV is different from that of many other types of cancer, especially solid tumors, under-reporting is possible. Therefore, we also used health claims data from Medicare services to estimate the incidence of PV among individuals 65 years and older. SEER data suggest that the age-adjusted incidence rate of PV was 0.87 per 100,000 per year (95% confidence interval 0.83 – 0.91) during 2001 – 2003, which is lower than the estimates from other studies (Ania BJ et al. Trends in the incidence of polycythemia vera among Olmsted County, Minnesota residents, 1935–1989. Am J Hematol1994;47(2):89–93. Johansson P. Epidemiology of the myeloproliferative disorders polycythemia vera and essential thrombocythemia. Semin Thromb Hemost2006;32(3):171–3). The incidence of PV increased with age and was higher in men and white individuals than in women and other racial groups. The SEER-derived age-adjusted incidence rate of PV was 4.1 per 100,000 per year among individuals 65 years and older during 2003, which is considerably lower than the estimates made from nationwide Medicare claims data in the same age group during the same year, suggesting possible under-reporting to SEER. The addition of PV to SEER reporting represents a major step in generating population-based epidemiologic data for this understudied malignancy. However, it is critical to ensure the completeness in the ascertainment and reporting of PV so high-quality SEER data can be utilized to facilitate much needed research on the etiology and outcomes of PV, as well as other myeloproliferative disorders.