ALBERT

Description: Vitamin D insufficiency is common globally and low levels are linked to higher cancer incidence. Although vitamin D insufficiency is related to inferior prognosis in some cancers, no data exist for chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). We evaluated the relationship of 25(OH)D serum levels with time-to-treatment (TTT) and overall survival (OS) in newly diagnosed CLL patients participating in a prospective cohort study (discovery cohort) and a separate cohort of previously untreated patients participating in an observational study (confirmation cohort). Of 390 CLL patients in the discovery cohort, 119 (30.5%) were 25(OH)D insufficient. After a median follow-up of 3 years, TTT (hazard ratio[HR] = 1.66; P = .005) and OS (HR = 2.39; P = .01) were shorter for 25(OH)D-insufficient patients. In the validation cohort, 61 of 153 patients (39.9%) were 25(OH)D insufficient. After a median follow-up of 9.9 years, TTT (HR = 1.59; P = .05) and OS (HR 1.63; P = .06) were again shorter for 25(OH)D-insufficient patients. On pooled multivariable analysis of patients in both cohorts adjusting for age, sex, Rai stage, CD38 status, ZAP-70 status, immunoglobulin heavy chain variable (IGHV) gene mutation status, CD49d status, and cytogenetic abnormalities assessed by interphase fluorescent in situ hybridization testing, 25(OH)D insufficiency remained an independent predictor of TTT (HR = 1.47; P = .008), although the association with OS was not significant (HR = 1.47; P = .07). Vitamin D insufficiency is associated with inferior TTT and OS in CLL patients. Whether normalizing vitamin D levels in deficient CLL patients would improve outcome merits clinical testing.

Description: This is the first study to investigate the efficacy of intravenous iron in treating fatigue in nonanemic patients with low serum ferritin concentration. In a randomized, double-blinded, placebo-controlled study, 90 premenopausal women presenting with fatigue, serum ferritin ≤ 50 ng/mL, and hemoglobin ≥ 120 g/L were randomized to receive either 800 mg of intravenous iron (III)–hydroxide sucrose or intravenous placebo. Fatigue and serum iron status were assessed at baseline and after 6 and 12 weeks. Median fatigue at baseline was 4.5 (on a 0-10 scale). Fatigue decreased during the initial 6 weeks by 1.1 in the iron group compared with 0.7 in the placebo group (P = .07). Efficacy of iron was bound to depleted iron stores: In patients with baseline serum ferritin ≤ 15 ng/mL, fatigue decreased by 1.8 in the iron group compared with 0.4 in the placebo group (P = .005), and 82% of iron-treated compared with 47% of placebo-treated patients reported improved fatigue (P = .03). Drug-associated adverse events were observed in 21% of iron-treated patients and in 7% of placebo-treated patients (P = .05); none of these events was serious. Intravenous administration of iron improved fatigue in iron-deficient, nonanemic women with a good safety and tolerability profile. The efficacy of intravenous iron was bound to a serum ferritin concentration ≤ 15 ng/mL. This study was registered at the International Standard Randomized Controlled Trial Number Register (www.isrctn.org) as ISRCTN78430425.

Description: Recruitment of polymorphonuclear neutrophils (PMNs) remains a paramount prerequisite in innate immune defense and a critical cofounder in inflammatory vascular disease. Neutrophil recruitment comprises a cascade of concerted events allowing for capture, adhesion and extravasation of the leukocyte. Whereas PMN rolling, binding, and diapedesis are well characterized, receptor-mediated processes, mechanisms attenuating the electrostatic repulsion between the negatively charged glycocalyx of leukocyte and endothelium remain poorly understood. We provide evidence for myeloperoxidase (MPO), an abundant PMN-derived heme protein, facilitating PMN recruitment by its positive surface charge. In vitro, MPO evoked highly directed PMN motility, which was solely dependent on electrostatic interactions with the leukocyte's surface. In vivo, PMN recruitment was shown to be MPO-dependent in a model of hepatic ischemia and reperfusion, upon intraportal delivery of MPO and in the cremaster muscle exposed to local inflammation or to intraarterial MPO application. Given MPO's affinity to both the endothelial and the leukocyte's surface, MPO evolves as a mediator of PMN recruitment because of its positive surface charge. This electrostatic MPO effect not only displays a so far unrecognized, catalysis-independent function of the enzyme, but also highlights a principal mechanism of PMN attraction driven by physical forces.

Description: Abstract 195 ADAMTS13 contains multiple free thiols on its surface, which may form disulfide bonds with surface-exposed free thiols on plasma-derived von Willebrand factor (VWF). This interaction may prevent lateral association of apposed VWF under arterial shear stress. However, the functional consequence of ADAMTS13-VWF interaction without proteolysis is not known. We hypothesize that the interaction between the C-terminus of ADAMTS13 and the C-terminus of VWF inhibits thrombus formation under shear stress. Using a BioFlux microfluidic system, we showed that under arterial shear stress, 10 dyn/cm2, fluorescein-labeled platelets from PPACK (thrombin inhibitor) anti-coagulated human whole blood adhered to collagen (type I)-coated surface in a time-dependent manner. Addition of human recombinant full-length ADAMTS13 (10 nM) into whole blood dramatically reduced the surface coverage of fluorescein-labeled platelets. Conversely, addition of an inhibitory polyclonal anti-ADAMTS13 IgGs (150 ug/ml) to whole blood dramatically accelerated the accumulation of fluorescein-labeled platelets. These results suggest that this microfluidic system is highly sensitive for the assessment of anti-thrombotic function of ADAMTS13. Under the same conditions, we were able to further show that addition of recombinant C-terminal fragment of ADAMTS13 comprising of the 5th to 8th thrombospondin type 1 (TSP1) repeats and two CUB domains (T5C) or the 2nd to 8th TSP1 repeats and two CUB domains (T2C) into whole blood also inhibited the surface coverage of fluorescein-labeled platelets on collagen-coated surface in a concentration-dependent manner. In the presence of 0.1 μM and 0.5 μM of recombinant T2C or T5C, the surface coverage of fluorescein-labeled platelets was reduced by ∼40% and ∼60%, respectively. The inhibitory activity of these recombinant C-terminal fragments was nearly abolished if pre-treated with 40 mM of N-ethylmaleimide which blocked surface-exposed free thiols. Moreover, recombinant CUB domains at the highest concentration tested (1.0 μM) did not appear to alter the surface coverage of fluorecein-labeled platelets under the same conditions. These results suggest that the C-terminal TSP1 repeats of ADAMTS13 inhibit platelet adhesion and aggretion or thrombus formation through thiol-thiol interactions between ADAMTS13 and VWF (or other proteins). We conclude that the C-terminal TSP1 repeats may modulate thrombus formation independent of proteolytic activity. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 22 For many years it has been evident that it is challenging to express recombinant factor VIII (FVIII) in vitro and in vivo. In vitro studies suggest that high levels of FVIII expression can lead to cellular stress. We have demonstrated that adeno-associated viral (AAV) vector delivery results in long-term expression of therapeutic levels of FVIII in hemophilia A (HA) dogs up 10% of normal. In this model transgene expression is restricted to a portion of liver cells resulting in sustained FVIII levels. Notably, in dogs FVIII expression is sustained for periods longer than 7 years. Conceivably, the increased load per cell for cellular processing of FVIII may impact the cell's ability to synthesize and secrete functional FVIII, activation of cellular stress and the potential for immune responses. We sought to determine whether cellular stress and immune responses to the transgene are increased by overexpression of FVIII in mice by AAV vectors. Using AAV to deliver FVIII as a B-domain deleted single chain (single chain approach) or as two separate chains (light and heavy chains) (two chain approach), we analyzed dose-dependent FVIII synthesis and its cellular impact. We hypothesized that high levels of FVIII expression after AAV-mediated delivery of FVIII may induce cellular stress. HA mice were administered AAV serotype 8 (AAV8) vector in 3 groups: (1) two-chain approach (2) single chain approach or (3) AAV empty capsid (control). Three total AAV doses were administered: 1×1010 vector genomes/mouse (low dose), 5×1010 vg/mouse (mid-dose) and 2.5×1011 vg/mouse (high dose). FVIII antigen levels (heavy and light chain) and anti-cFVIII IgG antibodies were detected by ELISA at a series of time points post vector administration until the terminal time points (1, 2, 4, 8, 12 and 24 wks). As we previously observed, after single chain delivery we detect equivalent amounts of heavy chain and light chain in the circulation by ELISA that correlates with activity. However, in the two-chain approach we observe that the light chain is 〉2-fold higher than the heavy chain in the circulation and that the activity correlates with the amount of heavy chain. We observe a dose-dependent increase in FVIII expression and dose-dependent anti-cFVIII IgG antibody titers. The kinetics of FVIII expression and antibody formation are different for the two-chain delivery compared to the single chain delivery. For the two-chain delivery, we observe AAV dose-dependent peak FVIII expression within 1 week (30, 100, or 400 ng/ml, respective of dose) followed by the onset of anti-FVIII IgG2 antibodies by 4 weeks (16, 27, 52 μg/ml, respective of dose). For single chain delivery, we observe FVIII expression within 1 week and low level antibody titers by 4 weeks that increase dramatically by 12 weeks (14, 21, 38 μg/ml, respective of dose). Thus, we observe a more gradual increase in antibody titers in the single chain compared to the two-chain delivery but at late time points the immunogenicity of both approaches is indistinguishable. RNA was isolated from the livers of the mice at the terminal time points for quantitative PCR analysis of two key components of the unfolded protein response signaling network, BiP and CHOP. We compared the two-chain and single chain AAV delivery of FVIII alongside animals injected with AAV empty capsid that did not express FVIII. A tunicamycin treated positive control had an increase in BiP (54-fold) and CHOP (74-fold) expression compared to untreated HA mice. There were mild elevations (2–3-fold) of BiP and/or CHOP in some animals observed at week 1 in all three treatment groups. Only at 12 weeks post vector administration were significant increases in BiP (〉70 fold) and CHOP (〉4 fold) observed in the single chain treated group at the high dose expressing 〉300% but not the two-chain approach or empty capsid. These studies suggest that supraphysiological expression (〉100%) of BDD-cFVIII may increase the likelihood of an immune response to FVIII and cellular stress. Further studies may determine if there is a relationship between high FVIII expression, cellular stress and immune responses to FVIII. Thus, there is a threshold of FVIII expression levels that may prove unsafe. Moreover, these data are in agreement with the lack of evidence of cellular toxicity and immunogenicity in HA dogs expressing therapeutic levels of FVIII by AAV vectors. Disclosures: Lange: Bayer Healthcare: Research Funding. Altynova:Bayer Healthcare: Research Funding. Sabatino:Bayer Healthcare: Research Funding.

Description: Abstract 4184 Introduction: FACT-MM was developed with the aim to create a disease-specific, patient-reported outcomes (PRO) measure as part of the FACT measurement system to assess multiple myeloma (MM)-related symptoms. Literature review identified 52 MM specific symptoms and concerns. 13 MM expert clinicians rated these 52 items on relevance to health-related quality of life (HRQL) for MM patients and added 11 items for comprehensive PRO assessment in MM. These 63 candidate items were rated by 13 MM patients recruited through the International Myeloma Foundation website. Disease-related symptoms and concerns were described and provided by patients through free-text comments. Information from both the MM expert clinician and MM patient surveys including free-text items was analyzed and 14 highest ranked items were selected for the FACT-MM. The FACT-MM subscale (score 0–56), the FACT-G physical and functional well-being subscales (score 0–28), and the FACT-Neurotoxicity (FACT-Ntx) subscale (score 0–44) was administered to 48 E1A05 participants to assess disease and treatment-related symptoms of patients with newly diagnosed MM receiving 8 cycles of VRd versus Vd. Methods: In this study, the first three of seven sequential assessments were evaluated: baseline, cycle 5 and end of treatment (after cycle 8 or early diconstinuation). Instruments were scored as per the FACT scoring guidelines. Descriptive statistics were provided for each timepoint and changes in scores from baseline. The Wilcoxon rank sum test was used to assess differences in scores by ISS stage and ECOG PS. Pearson correlation coefficients were obtained between the scores. Cronbach's alpha was used to evaluate internal consistency of the FACT-MM. Results: At baseline and end of treatment, 46 and 41 patients, respectively, completed assessments. The FACT-MM demonstrated good to very good internal consistency (Cronbach alpha 0.79 – 0.89). The FACT-MM subscale was significantly correlated with the FACT physical and functional well-being subscales at baseline (r = 0.72), cycle 5 (r = 0.64; r = 0.49) and end of treatment (r = 0.72; r = 0.66). All scores declined modestly by cycle 5 and end of treatment from baseline. While sample size was limited, there appeared association with ECOG PS with higher scores for patients with PS 0 status. Conclusions: The 14-item FACT-MM scale is feasible for use to measure myeloma-related symptoms and has demonstrated acceptable psychometric properties based on findings from E1A05, an ECOG myeloma trial. Disclosures: Cella: Novartis: Research Funding. Fonseca:Consulting:Genzyme, Medtronic, BMS, Amgen, Otsuka, Celgene, Intellikine, Lilly Research Support: Cylene, Onyz, Celgene: Consultancy, Research Funding.

Description: Abstract 5071 Background: Multiple myeloma (MM) is de second most common haematological malignancy in adults worldwide. MM is common in the elderly. While the general life expectancy is increasing an ever increasing number of patients has to be expected. In the last decade treatment strategies are changed continuously because of the introduction of novel agents and allogeneic and autologous stem cell transplantation. In randomized controlled trials, overall survival in patients up to 65 years is improving convincing. In contrast with results in older patients. We studied data of patients treated outside clinical trials derived from the population based registry in the Netherlands to recognize trends in incidence en survival during 1989–2009. Patients and methods: We included all patients with newly diagnosed MM in the period 1989 – 2009 who were recorded in the Netherlands Cancer Registry (n =16.822 ). Follow-up was until January, 2010. We calculated the yearly age-standardised incidence rates for males and females and age-specific incidence rates in 10 year age groups for both sexes separately and combined. Changes in incidence were evaluated by calculating the estimated annual percentage change (EAPC). We then calculated relative survival, which may be interpreted as disease-specific survival within a cancer patient population. Traditional cohort-based, relative survival analysis was applied for patients diagnosed during 1989–2009. Since follow-up was available until 2010, 5 year relative survival for patients diagnosed in 2004–2009 was estimated using period-based relative survival analysis. Results: The number of newly diagnosed MM cases rose between 1989 and 2009 from 631 to 968 cases respectively. Significantly more males were diagnosed than females over time (p=0.01). Furthermore the proportion of male patients increased slightly over these time periods. However, the overall age standardised incidence rate for males and females remained stable over time but was higher among males than females. The median age at diagnosis was 71 years (p10-P90 range 53–84) and stable over time (p=0.07). Incidence was highest in the 70–79 age group for both sexes. However, because of the aging population the age-specific incidence rates (ASIR) were highest for patients aged 80+ years for both sexes. Within specific age groups significant changes were seen. In the population 50–59 years, the ASIR increased from 5.0 per 100,000 in 1989 to 6.9 in 2009 (EAPC 1989–2009 = + 0.7%; 95% CI: 0.0 –1.3). A decrease was seen in females aged 80+ years from 25.1 per 100,000 in 1989 to 22.4 in 2009 (EAPC 1989–2009 = −1,0; 95% CI: −1.8; −0.2). In the overall patient population the 1-year relative survival increased only slightly from 72% to 77% between 1989 and 2009. 5-year relative survival increased from 28% to 37%. Small improvements in survival were observed for all age groups in the past two decades except for patients aged 80+ years. Relative survival decreased with increasing age. In contrast, in the group aged 40–64 years improvements are already detectable from 1994 on. In 2004–2009 the highest 5-year relative survival, 62%, was seen in patients 40–49 year of age. However the strongest improvement over time was observed among the group 50–59 years. Conclusion: Although the average annual age-adjusted incidence rate remained stable from 1989–2009, the number of newly diagnosed MM patients increased because of the aging population. Relative survival increased slowly but continuously in time for patients until 80 years of age with strongest increase seen in patients up to 64 years of age. Improvement for these younger patients is most likely caused by the introduction of novel agents based regiments as well as by the introduction of high dose chemotherapy followed by stem cell transplantation. Our findings in trends of incidence and survival of MM are similar to those reported in other western populations. Disclosures: Sonneveld: Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen-Cilag: Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Membership on an entity's Board of Directors or advisory committees, Research Funding; Millennium: Membership on an entity's Board of Directors or advisory committees.

Description: Abstract 475FN2 Background: An IMiDs® immunomodulatory agent, Len has a dual mechanism of action: its tumoricidal effect directly leads to tumor cell death, and its immunomodulatory effect may keep the tumor in remission. A phase 3, randomized, placebo (Pbo)-controlled trial, MM-015 compares MPR-R with fixed-duration MPR and MP induction in transplant-ineligible NDMM pts. Interim results showed unprecedented reduction in disease progression risk with MPR-R (Palumbo et al, IMW 2011); this analysis focuses on pts aged 65–75 yrs in whom the greatest benefit was observed. Methods: A total of 459 pts aged ≥ 65 yrs with NDMM were enrolled. Induction consisted of nine 28-day cycles of melphalan 0.18 mg/kg (D1-4), prednisone 2 mg/kg (D1-4), and Len 10 mg (D1-21) (MPR-R and MPR) or melphalan and prednisone with Pbo (MP). After induction, MPR-R pts received Len 10 mg (D1-21) maintenance until progression; MPR and MP pts received Pbo. Pts with progressive disease (PD) could enroll in an open-label extension phase to receive Len 25 mg (D1-21) ± dexamethasone 40 mg (D1-4, 9–12, and 17–20). This analysis includes data up to Feb 28, 2011 (median follow-up, 30 mos). Results: There were 116/152 (76%), 116/153 (76%), and 116/154 (75%) of MPR-R, MPR, and MP pts, respectively, aged 65–75 yrs. Nearly 50% had ISS stage III disease, 〉 40% had β2-microglobulin 〉 5.5 mg/L, and 40% had CrCL 〈 60 mL/min. With a median follow-up of 30 mos, MPR-R reduced progression risk by 70% and significantly prolonged median PFS (31 mos) vs MP (12 mos; hazard ratio [HR]: 0.30 [95% CI, 0.20–0.45]; P

Description: POEMS syndrome is a rare clonal plasma cell disorder without standard treatment. Based on the efficacy and low toxicity of a combination of melphalan and dexamethasone (MDex) for light chain amyloidosis, we conducted a prospective study of MDex treatment for patients with newly diagnosed POEMS syndrome. Thirty-one patients (19 men) were enrolled and the median age at the time of diagnosis was 44 years (range, 32-68 years). All patients received 12 cycles of MDex treatment. Twenty-five patients (80.6%) achieved hematologic response including 12 (38.7%) complete remission and 13 (41.9%) partial remission. Of all 31 patients, the neurologic response rate was 100%, assessed by overall neuropathy limitation scale (ONLS). The initial neurologic response was observed in 24 patients (77.4%) at 3 months after treatment and the median time to maximal neurologic response was 12 months (range, 3-15 months). Moreover, MDex substantially improved the level of serum vascular endothelial growth factor and relieved organomegaly, extravascular volume overload, and pulmonary hypertension. Only 6 patients (19.3%) suffered from grade 3 adverse events during treatment. All patients are alive and free of neurologic relapse after the median follow-up time of 21 months. Therefore, MDex is an effective and well-tolerated treatment option for patients with newly diagnosed POEMS syndrome.

Description: Multiple mechanisms operate to ensure T-cell tolerance toward self-antigens. Three main processes have been described: clonal deletion, anergy, and deviation to CD4+ regulatory T cells (Tregs) that suppress autoreactive T cells that have escaped the first 2 mechanisms. Although it is accepted that dendritic cells (DCs) and B cells contribute in maintaining T-cell tolerance to self-antigens, their relative contribution and the processes involved under physiologic conditions remain only partially characterized. In this study, we used different transgenic mouse models to obtain chimeras where a neo self-antigen is expressed by thymic epithelium and/or by DCs or B cells. We found that expression of cognate ligand in the thymus enhances antigen-specific FoxP3+ cells independently of whether the self-antigen is expressed on thymic epithelium or only on DCs, but not on B cells. On the contrary, self-antigen expression by B cells was very efficient in inducing FoxP3+ cells in the periphery, whereas self-antigen expression by DC led mainly to deletion and anergy of antigen-specific FoxP3− cells. The results presented in this study underline the role of B cells in Treg induction and may have important implications in clinical protocols aimed at the peripheral expansion of Tregs in patients.

Description: Treatment-related mortality (TRM) is important in acute lymphoblastic leukemia and acute myeloid leukemia (AML); however, little is known about how TRM is defined across trials. Two major problems are related to what constitutes treatment versus disease-related cause of death and to TRM attribution (for example, death because of infection or hemorrhage). To address the former, we conducted a systematic review of randomized therapeutic pediatric acute leukemia and adult/pediatric acute promyelocytic leukemia trials and any study type focused on TRM in pediatric acute leukemia. We described definitions used for TRM. Sixty-six studies were included. Few therapeutic pediatric acute lymphoblastic leukemia studies (2/32, 6.3%) provided definitions for TRM, whereas more therapeutic pediatric AML studies (6/9, 66.7%) provided definitions. There was great heterogeneity in TRM classification. The authors of most studies relied on deaths during induction or in remission to delineate whether a death was TRM. However, 44.4% of therapeutic AML studies used death within a specific time frame to delineate TRM. We suggest that a consistent approach to defining and determining attribution for TRM in acute leukemia is an important future goal. Harmonization of definitions across the age spectrum would allow comparisons between pediatric and adult studies.

Description: Using proteins in a therapeutic context often requires engineering to modify functionality and enhance efficacy. We have previously reported that the therapeutic antileukemic protein macromolecule Escherichia coli L-asparaginase is degraded by leukemic lysosomal cysteine proteases. In the present study, we successfully engineered L-asparaginaseto resist proteolytic cleavage and at the same time improve activity. We employed a novel combination of mutant sampling using a genetic algorithm in tandem with flexibility studies using molecular dynamics to investigate the impact of lid-loop and mutations on drug activity. Applying these methods, we successfully predicted the more active L-asparaginase mutants N24T and N24A. For the latter, a unique hydrogen bond network contributes to higher activity. Furthermore, interface mutations controlling secondary glutaminase activity demonstrated the importance of this enzymatic activity for drug cytotoxicity. All selected mutants were expressed, purified, and tested for activity and for their ability to form the active tetrameric form. By introducing the N24A and N24A R195S mutations to the drug L-asparaginase, we are a step closer to individualized drug design.

Description: Shwachman-Diamond syndrome (SDS) results from mutations in the SBDS gene, characterized by exocrine pancreatic insufficiency and hematologic and skeletal abnormalities. Neutropenia and neutrophil dysfunction are hallmark features of SDS; however, causes for the bone defects are unknown. Dysfunction of bone-resorbing osteoclasts, formed by the fusion of monocytic progenitors derived from the same granulocytic precursors as neutrophils, could be responsible. We report that Sbds is required for in vitro and in vivo osteoclastogenesis (OCG). Sbds-null murine monocytes formed osteoclasts of reduced number and size because of impaired migration and fusion required for OCG. Phenotypically, Sbds-null mice exhibited low-turnover osteoporosis consistent with findings in SDS patients. Western blotting of Rho GTPases that control actin dynamics and migration showed a 5-fold decrease in Rac2, whereas Rac1, Cdc42, and RhoA were unchanged or only mildly reduced. Although migration was rescued on Rac2 supplementation, OCG was not. This was attributed to impaired signaling downstream of receptor activator of nuclear factor-κB (RANK) and reduced expression of the RANK-ligand-dependent fusion receptor DC-STAMP. We conclude that Sbds is required for OCG by regulating monocyte migration via Rac2 and osteoclast differentiation signaling downstream of RANK. Impaired osteoclast formation could disrupt bone homeostasis, resulting in skeletal abnormalities seen in SDS patients.

Description: Bone marrow transplantation (BMT) is relatively effective for the treatment of lysosomal storage diseases. To better understand the contribution of specific hematopoietic lineages to the efficacy of BMT, we transplanted β-glucuronidase–positive mononuclear phagocytes derived from either the peritoneum or from bone marrow in vitro into syngeneic recipients with mucopolysaccharidosis type VII (MPS VII). Cell surface marking studies indicate that the bone marrow-derived cells are less mature than the peritoneal macrophages. However, both cell types retain the ability to home to tissues rich in cells of the reticuloendothelial system after intravenous injection into MPS VII mice. The half-life of both types of donor macrophages is approximately 7 days, and some cells persist for at least 30 days. In several tissues, therapeutic levels of β-glucuronidase are present, and histopathologic analysis demonstrates that lysosomal storage is dramatically reduced in the liver and spleen. Macrophages intravenously injected into newborn MPS VII mice localize to the same tissues as adult mice but are also observed in the meninges and parenchyma of the brain. These data suggest that macrophages play a significant role in the therapeutic efficacy of BMT for lysosomal storage diseases and may have implications for treatments such as gene therapy.

Description: In anaplastic large-cell lymphoma (ALCL), the (2;5) chromosomal translocation creates a fusion gene encoding the 80-kD NPM-ALK hybrid protein. This report describes three new monoclonal antibodies, two of which recognize, by Western blotting, the N-terminal portion of NPM present in the NPM-ALK fusion protein and also in two other NPM fusion proteins (NPM-RAR and NPM-MLF1). The third antibody recognizes the C-terminal portion (deleted in NPM-ALK) and reacts only with wild-type NPM. The three antibodies immunostain wild-type NPM (in paraffin-embedded normal tissue samples) in cell nuclei and in the cytoplasm of mitotic cells. Cerebral neurones, exceptionally, show diffuse cytoplasmic labeling. In contrast to normal tissues, the two antibodies against the N-terminal portion of NPM labeled the cytoplasm of neoplastic cells, in four ALK-positive ALCL, reflecting their reactivity with NPM-ALK fusion protein, whereas the antibody to the C-terminal NPM epitope labeled only cell nuclei. Immunocytochemical labeling with these antibodies can therefore confirm that an ALK-positive lymphoma expresses NPM-ALK (rather than a variant ALK-fusion protein) and may also provide evidence for chromosomal anomalies involving the NPM gene other than the classical (2;5) translocation.

Description: Thrombin is a positive mediator of thrombus formation through the proteolytic activation of protease-activated receptors (PARs), fibrinogen, factor XI (fXI), and other substrates, and a negative regulator through activation of protein C, a natural anticoagulant with anti-inflammatory/cytoprotective properties. Protease-engineering studies have established that 2 active-site substitutions, W215A and E217A (fIIWE), result in dramatically reduced catalytic efficiency with procoagulant substrates while largely preserving thrombomodulin (TM)–dependent protein C activation. To explore the hypothesis that a prothrombin variant favoring antithrombotic pathways would be compatible with development but limit inflammatory processes in vivo, we generated mice carrying the fIIWE mutations within the endogenous prothrombin gene. Unlike fII-null embryos, fIIWE/WE mice uniformly developed to term. Nevertheless, these mice ultimately succumbed to spontaneous bleeding events shortly after birth. Heterozygous fIIWT/WE mice were viable and fertile despite a shift toward an antithrombotic phenotype exemplified by prolonged tail-bleeding times and times-to-occlusion after FeCl3 vessel injury. More interestingly, prothrombinWE expression significantly ameliorated the development of inflammatory joint disease in mice challenged with collagen-induced arthritis (CIA). The administration of active recombinant thrombinWE also suppressed the development of CIA in wild-type mice. These studies provide a proof-of-principle that pro/thrombin variants engineered with altered substrate specificity may offer therapeutic opportunities for limiting inflammatory disease processes.

Description: Thrombomodulin (TM) is a predominantly endothelial transmembrane glycoprotein that modulates hemostatic function through a domain that controls thrombin-mediated proteolysis and an N-terminal lectin-like domain that controls inflammatory processes. To test the hypothesis that TM is a determinant of malignancy and dissect the importance of these functional domains in cancer biology, metastatic potential was evaluated in TMPro mice expressing a mutant form of TM with reduced thrombin affinity and TMLeD mice lacking the N-terminal lectin-like domain. Studies of TMPro mice revealed that TM is a powerful determinant of hematogenous metastasis. TMPro mice exhibited a strongly prometastatic phenotype relative to control mice that was found to result from increased survival of tumor cells newly localized to the lung rather than any alteration in tumor growth. The impact of the TMPro mutation on metastasis was dependent on both tumor cell-associated tissue factor and thrombin procoagulant function. In contrast, expression of a mutant form of TM lacking the lectin-like domain had no significant impact on metastasis. These studies directly demonstrate for the first time that TM-mediated regulation of tumor cell-driven procoagulant function strongly influences metastatic potential and suggest that endothelial cell-associated modulators of hemostasis may represent novel therapeutic targets in limiting tumor dissemination.

Description: Whether long-term use of vitamin K antagonists (VKAs) might affect the incidence of cancer is a longstanding hypothesis. We conducted a population-based study including all cancer- and thromboembolism-free patients of our health area; study groups were defined according to chronic anticoagulant use to VKA-exposed and control groups. Cancer incidence and cancer-related and overall mortality was assessed in both groups. 76 008 patients (3231 VKA-exposed and 72 777 control subjects) were followed-up for 8.2 (± 3.2) years. After adjusting for age, sex, and time-to-event, the hazard ratio of newly diagnosed cancer in the exposed group was 0.88 (95% confidence interval [95% CI] 0.80-0.98; P 〈 .015). VKA-exposed patients were less likely to develop prostate cancer, 0.69 (95% CI 0.50-0.97; P = .008). The adjusted hazard ratio for cancer-related and overall mortality was 1.07 (95% CI 0.92-1.24) and 1.12 (95% CI 1.05-1.19), respectively. These results support the hypothesis that anticoagulation might have a protective effect on cancer development, especially prostate cancer.

Description: Patients referred to tertiary care centers occasionally may have their diagnostic procedures repeated and have a final diagnosis that differs from that of the referring center. The aim of this study was to evaluate discordance rates and their clinical implications in the diagnosis of patients with myelodysplastic syndrome (MDS) referred to a tertiary center. We analyzed 915 patients with MDS who were referred to M. D. Anderson Cancer Center between September 2005 and December 2009. Discordance in the diagnosis was documented in 109 (12%) patients, with a majority reclassified as having higher-risk disease by French-American-British (67%) or by International Prognostic Scoring System (77%) with implications for therapy selection and prognosis calculation. These results demonstrate the complexity of the diagnosis of MDS and highlight the need for confirmation of diagnosis when in doubt.

Description: Abstract 2283 Introduction: von Willebrand factor (VWF) acts as bridging molecule between platelets and vessel wall or as a career for plasma factor VIII (FVIII). Earlier reports using flow chamber had revealed that VWF acts as an “initiator” through its interactionwith glycoprotein (GP) Ib, whereas fibrinogen, via its binding to GP IIb-IIIa, acts as a “stabilizer” against high shear. VWD is categorized as partial or complete quantitative defect (type 1 or 3) or qualitative defect (type 2) of VWF based on laboratory tests, such as VWF antigen (VWF:Ag), VWF ristocetin cofactor activity (VWF:RCo), and FVIII activity (FVIII:C). However, the diagnosis of VWD remains difficult because the clinical and laboratory phenotype has wide-spectrum. An assay reflecting clinical phenotypes of VWD and effect of the treatment would be helpful for clinicians. Methods: We evaluated a thrombus formation with a new applicative microchip flow chamber instrument, total-thrombus-formation analysis system (T-TAS®). Citrated or hirudin-added blood from healthy volunteers (n=5) or 3 patients with VWD [symptomatic type 1 (S-1), asymptomatic type 1 (AS-1), and symptomatic type 3 (S-3)] were utilized. Normal blood was mixed with inhibitor for GP Ib (OS-1), GP IIb-IIIa (abciximab) and monoclonal antibody against for VWF (mAb-VWF). Patients' blood was infused with FVIII/VWF concentrates in (ex) vivo. Re-calcified citrated blood (450 μl) added corn trypsin inhibitor (30 μg/ml) was infused to AR chip of T-TAS at constant flow rate (240–600 s−1), which surface was coated by collagen and tissue factor. Hirudin-added blood (350 μl) was infused to PL chip of T-TAS at higher shear (1,000–2,000 s−1) which surface was coated by collagen. Flow pressure curve was plotted and time to 10 kPa (T10) was evaluated. Furthermore, flow images were recorded with a micro camera. AR chip promoted white thrombus formation (WTF) which reflected both platelet aggregation and fibrin generation, whilst PL chip did only platelet thrombus formation (PTF). Rotational thromboerastometry (ROTEM) were simultaneously investigated. Results: Both abciximab (0.5–2.0 μg/ml) and OS-1 (100–400 nM) inhibited WTF in AR chip dose-dependently. OS-1 (200 nM) inhibited WTF partially at 240 s−1 (T10 15.4±1.6 min, control 8.9±0.4 min), but completely at 600 s−1 (T10 〉30 min, control 7.5±0.2 min). In PL chip, both agents inhibited PTF at much lower dose than those in AR chip. ROTEM parameters showed little change in both agents. Using mAb-VWF, similar results to OS-1 were obtained. These data showed that GP Ib-VWF interaction was shear-dependent, consistent with earlier reports. In in (ex) vivo assays, S-1 and AS-1 had comparable VWF levels (VWF:Ag/VWF:RCo 20%/6.4% and 5.8%/3.2%, respectively) in spite of clear difference of clinical phenotype. ROTEM parameters of S-1 were rather better than those of AS-1 likely reflecting FVIII:C (60% and 7.2%). Interestingly, however, PTF in PL chip (at 1,000 s−1) showed significant delay of T10 in S-1 (9.0 min, control 4.1±0.5 min) compared to AS-1 (5.2 min) and after in vivo infusion of FVIII/VWF concentrates, T10 in S-1 was improved (5.0 min). In S-3, ROTEM parameters declined reflecting low FVIII:C (1.2%), and prolonged T10 (〉30 min) in AR chip likely reflected complete defect of VWF:Ag (

Description: Gene expression profiling (GEP) of purified plasma cells 48 hours after thalidomide and dexamethasone test doses showed these agents' mechanisms of action and provided prognostic information for untreated myeloma patients on Total Therapy 2 (TT2). Bortezomib was added in Total Therapy 3 (TT3), and 48 hours after bortezomib GEP analysis identified 80 highly survival-discriminatory genes in a training set of 142 TT3A patients that were validated in 128 patients receiving TT3B. The 80-gene GEP model (GEP80) also distinguished outcomes when applied at baseline in both TT3 and TT2 protocols. In context of our validated 70-gene model (GEP70), the GEP80 model identified 9% of patients with a grave prognosis among those with GEP70-defined low-risk disease and 41% of patients with favorable prognosis among those with GEP70-defined high-risk disease. PMSD4 was 1 of 3 genes common to both models. Residing on chromosome 1q21, PSMD4 expression is highly sensitive to copy number. Both higher PSMD4 expression levels and higher 1q21 copy numbers affected clinical outcome adversely. GEP80 baseline-defined high risk, high lactate dehydrogenase, and low albumin were the only independent adverse variables surviving multivariate survival model. We are investigating whether second-generation proteasome inhibitors (eg, carfilzomib) can overcome resistance associated with high PSMD4 levels.

Description: Factor XI deficiency is associated with a bleeding diathesis, but factor XII deficiency is not, indicating that, in normal hemostasis, factor XI must be activated in vivo by a protease other than factor XIIa. Several groups have identified thrombin as the most likely activator of factor XI, although this reaction is slow in solution. Although certain nonphysiologic anionic polymers and surfaces have been shown to enhance factor XI activation by thrombin, the physiologic cofactor for this reaction is uncertain. Activated platelets secrete the highly anionic polymer polyphosphate, and our previous studies have shown that polyphosphate has potent procoagulant activity. We now report that polyphosphate potently accelerates factor XI activation by α-thrombin, β-thrombin, and factor XIa and that these reactions are supported by polyphosphate polymers of the size secreted by activated human platelets. We therefore propose that polyphosphate is a natural cofactor for factor XI activation in plasma that may help explain the role of factor XI in hemostasis and thrombosis.

Description: Recent studies have shown that long-term repopulating hematopoietic stem cells (HSCs) first appear in the aorta-gonad-mesonephros (AGM) region. Our immunohistochemistry study showed that TEK+cells existed in the AGM region. Approximately 5% of AGM cells were TEK+, and most of these were CD34+ and c-Kit+. We then established a coculture system of AGM cells using a stromal cell line, OP9, which is deficient in macrophage colony-stimulating factor (M-CSF). With this system, we showed that AGM cells at 10.5 days postcoitum (dpc) differentiated and proliferated into both hematopoietic and endothelial cells. Proliferating hematopoietic cells contained a significant number of colony-forming cells in culture (CFU-C) and in spleen (CFU-S). Among primary AGM cells at 10.5 dpc, sorted TEK+ AGM cells generated hematopoietic cells and platelet endothelial cell adhesion molecule (PECAM)-1+ endothelial cells on the OP9 stromal layer, while TEK− cells did not. When a ligand for TEK, angiopoietin-1, was added to the single-cell culture of AGM, endothelial cell growth was detected in the wells where hematopoietic colonies grew. Although the incidence was still low (1/135), we showed that single TEK+ cells generated hematopoietic cells and endothelial cells simultaneously, using a single-cell deposition system. This in vitro coculture system shows that the TEK+ fraction of primary AGM cells is a candidate for hemangioblasts, which can differentiate into both hematopoietic cells and endothelial cells.

Description: Several studies have found that high levels of reactive oxidative species (ROS) are associated with stem cell dysfunction. In the present study, we investigated the role of nuclear factor erythroid-2–related factor 2 (Nrf2), a master regulator of the antioxidant response, and found that it is required for hematopoietic stem progenitor cell (HSPC) survival and myeloid development. Although the loss of Nrf2 leads to increased ROS in most tissues, basal ROS levels in Nrf2-deficient (Nrf2−/−) BM were not elevated compared with wild-type. Nrf2−/− HSPCs, however, had increased rates of spontaneous apoptosis and showed decreased survival when exposed to oxidative stress. Nrf2−/− BM demonstrated defective stem cell function, as evidenced by reduced chimerism after transplantation that was not rescued by treatment with the antioxidant N-acetyl cysteine. Gene-expression profiling revealed that the levels of prosurvival cytokines were reduced in Nrf2−/− HSPCs. Treatment with the cytokine G-CSF improved HSPC survival after exposure to oxidative stress and rescued the transplantation defect in Nrf2−/− cells despite increases in ROS induced by cytokine signaling. These findings demonstrate a critical role for Nrf2 in hematopoiesis and stem cell survival that is independent of ROS levels.

Description: Reactive oxygen species (ROS) are highly destructive toward cellular macromolecules. However, moderate levels of ROS can contribute to normal cellular processes including signaling. Herein we evaluate the consequence of a pro-oxidant environment on hematopoietic homeostasis. The NF-E2 related factor 2 (Nrf2) transcription factor regulates genes related to ROS scavenging and detoxification. Nrf2 responds to altered cellular redox status, such as occurs with loss of antioxidant selenoproteins after deletion of the selenocysteine-tRNA gene (Trsp). Conditional knockout of the Trsp gene using Mx1-inducible Cre-recombinase leads to selenoprotein deficiency and anemia on a wild-type background, whereas Trsp:Nrf2 double deficiency dramatically exacerbates the anemia and increases intracellular hydrogen peroxide levels in erythroblasts. Results indicate that Nrf2 compensates for defective ROS scavenging when selenoproteins are lost from erythroid cells. We also observed thymus atrophy in single Trsp-conditional knockout mice, suggesting a requirement for selenoprotein function in T-cell differentiation within the thymus. Surprisingly, no changes were observed in the myelomonocytic or megakaryocytic populations. Therefore, our results show that selenoprotein activity and the Nrf2 gene battery are particularly important for oxidative homeostasis in erythrocytes and for the prevention of hemolytic anemia.

Description: Human induced pluripotent stem cells (iPSCs) bearing monogenic mutations have great potential for modeling disease phenotypes, screening candidate drugs, and cell replacement therapy provided the underlying disease-causing mutation can be corrected. Here, we report a homologous recombination-based approach to precisely correct the sickle cell disease (SCD) mutation in patient-derived iPSCs with 2 mutated β-globin alleles (βs/βs). Using a gene-targeting plasmid containing a loxP-flanked drug-resistant gene cassette to assist selection of rare targeted clones and zinc finger nucleases engineered to specifically stimulate homologous recombination at the βs locus, we achieved precise conversion of 1 mutated βs to the wild-type βA in SCD iPSCs. However, the resulting co-integration of the selection gene cassette into the first intron suppressed the corrected allele transcription. After Cre recombinase-mediated excision of this loxP-flanked selection gene cassette, we obtained “secondary” gene-corrected βs/βA heterozygous iPSCs that express at 25% to 40% level of the wild-type transcript when differentiated into erythrocytes. These data demonstrate that single nucleotide substitution in the human genome is feasible using human iPSCs. This study also provides a new strategy for gene therapy of monogenic diseases using patient-specific iPSCs, even if the underlying disease-causing mutation is not expressed in iPSCs.

Description: The Ldb1/GATA-1/TAL1/LMO2 complex mediates long-range interaction between the β-globin locus control region (LCR) and gene in adult mouse erythroid cells, but whether this complex mediates chromatin interactions at other developmental stages or in human cells is unknown. We investigated NLI (Ldb1 homolog) complex occupancy and chromatin conformation of the β-globin locus in human erythroid cells. In addition to the LCR, we found robust NLI complex occupancy at a site downstream of the Aγ-globin gene within sequences of BGL3, an intergenic RNA transcript. In cells primarily transcribing β-globin, BGL3 is not transcribed and BGL3 sequences are occupied by NLI core complex members, together with corepressor ETO2 and by γ-globin repressor BCL11A. The LCR and β-globin gene establish proximity in these cells. In contrast, when γ-globin transcription is reactivated in these cells, ETO2 participation in the NLI complex at BGL3 is diminished, as is BCL11A occupancy, and both BGL3 and γ-globin are transcribed. In these cells, proximity between the BGL3/γ-globin region and the LCR is established. We conclude that alternative NLI complexes mediate γ-globin transcription or silencing through long-range LCR interactions involving an intergenic site of noncoding RNA transcription and that ETO2 is critical to this process.

Description: Megakaryocytes generate platelets by remodeling their cytoplasm first into proplatelets and then into preplatelets, which undergo fission to generate platelets. Although the functions of microtubules and actin during platelet biogenesis have been defined, the role of the spectrin cytoskeleton is unknown. We investigated the function of the spectrin-based membrane skeleton in proplatelet and platelet production in murine megakaryocytes. Electron microscopy revealed that, like circulating platelets, proplatelets have a dense membrane skeleton, the main fibrous component of which is spectrin. Unlike other cells, megakaryocytes and their progeny express both erythroid and nonerythroid spectrins. Assembly of spectrin into tetramers is required for invaginated membrane system maturation and proplatelet extension, because expression of a spectrin tetramer–disrupting construct in megakaryocytes inhibits both processes. Incorporation of this spectrin-disrupting fragment into a novel permeabilized proplatelet system rapidly destabilizes proplatelets, causing blebbing and swelling. Spectrin tetramers also stabilize the “barbell shapes” of the penultimate stage in platelet production, because addition of the tetramer-disrupting construct converts these barbell shapes to spheres, demonstrating that membrane skeletal continuity maintains the elongated, pre-fission shape. The results of this study provide evidence for a role for spectrin in different steps of megakaryocyte development through its participation in the formation of invaginated membranes and in the maintenance of proplatelet structure.

Description: IIbb3 integrin is a heterodimeric receptor facilitating platelet aggregation. Both genes are on chromosome 17q21.32. Intergenic distance between them has been reported to be 125 to 260 kilobasepairs (kb) by pulsed-field gel electrophoresis (PFGE) genomic analysis, suggesting that they may be regulated coordinately during megakaryopoiesis. In contrast, other studies suggest these genes are greater than 2.0 megabasepairs (mb) apart. Because of the potential biological implications of having these two megakaryocytic-specific genes contiguous, we attempted to resolve this discrepancy. Taking advantage of large kindreds with mutations in either IIb or β3, we have developed a genetic linkage map between the thyroid receptor hormone-1 gene (THRA1) and β3 as follows: cen-THRA1-BRCA1-D17S579/IIb-β3-qter, with a distance of 1.3 centiMorgans (cM) between IIb and β3 and the two genes being oriented in the same direction. PFGE genomic and YAC clone analysis showed that the β3 gene is distal and ≥365 kb upstream of IIb. Additional restriction mapping shows IIb is linked to the erythrocyte band 3 (EPB3) gene, and β3 to the homeobox HOX2b gene. Analysis of IIb+-BAC and P1 clones confirm that the EPB3 gene is ∼110 kb downstream of the IIb gene. Sequencing the region surrounding the human IIb locus showed the Granulin gene ∼18 kb downstream to IIb, and the KIAA0553 gene ∼5.7 kb upstream. This organization is conserved in the murine sequence. These studies show that IIb and β3 are not closely linked, with IIb flanked by nonmegakaryocytic genes, and imply that they are unlikely to share common regulatory domains during megakaryopoiesis.

Description: Myeloid-derived suppressor cells (MDSCs) inhibit adaptive and innate immunity and accumulate in the blood of persons with cancer, chronic inflammation, trauma, infection, and stress. Some of the factors inducing their accumulation are known; however, mechanisms regulating their turnover have not been identified. Mass spectrometry showed prominent expression of apoptosis pathway proteins, suggesting that MDSC turnover may be regulated by Fas-FasL–mediated apoptosis. This hypothesis was confirmed by showing that blood MDSCs induced by 3 mouse tumors were Fas+ and apoptosed in response to Fas agonist in vitro and to activated FasL+ T cells in vivo. FasL-deficient mice contained significantly more blood MDSCs than FasL+/+ mice, and after removal of primary tumors MDSCs regressed in STAT6−/− and CD1−/− mice but not in STAT6−/−FasL−/− or CD1−/−FasL−/− mice. Fas+ macrophages and dendritic cells did not apoptose in response to activated T cells, indicating that Fas-FasL regulation of myeloid cells was restricted to MDSCs. These results identify a new mechanism regulating MDSC levels in vivo and show a retaliatory relationship between T cells and MDSCs in that MDSCs suppress T-cell activation; however, once activated, T cells mediate MDSC apoptosis.

Description: Abstract 41 Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-related death with a majority of the reported cases secondary to the infusion of antibodies (Abs) contained within the plasma/blood component. An experimental filter that removes IgG was developed. We hypothesize that filtration of plasma with antibodies to leukocyte antigens will decrease both antibody-mediated priming of PMNs and antibody-mediated TRALI in a two-event in vivo model. Methods: Human plasma was drawn from healthy volunteers and IgG concentrations were measured before and after filtration. Plasma was obtained from two multiparous female donors: one with antibodies to HLA-A2 and to DR7 and the other with antibodies against HNA-3a. These plasma samples were filtered (F-Plas) or left as an unmodified control (Plas) and the anti-leukocyte antibodies were measured in a blinded fashion in referral labs using flow cytometry and Luminex™ beads or standard granulocyte antibody detection assays. These plasma samples were then used to prime the fMLP-activated respiratory burst, measured as the SOD-inhibitable reduction of cytochrome c (nmol O2−/min), of PMNs from HNA-3a+ donors or donors homozygous donors for HLA-A2, respectively. For the two-event in vivo modeling rats were incubated with 2 μg/ml endotoxin (LPS, S. enteritides) or saline (NS) for 2 hours (first event) and then were transfused with heat-treated human plasma that contained 25 μg/ml of an antibody against the MHC class I antigen OX27 that was either filtered (or left unmodified) prior to infusion (second event) followed by Evans Blue dye (EBD). ALI was measured as %EBD leak from the plasma into the bronchoalveolar lavage fluid. Statistical differences were measured via paired (PMN priming) or independent (in vivo TRALI) ANOVA, and data are reported as the mean ± the standard error of the mean. *=p

Description: Clinical trials have demonstrated that rituximab improves overall survival in non-Hodgkin lymphoma (NHL), except in mantle cell lymphoma (MCL). We used Surveillance Epidemiology and End Results (SEER)–Medicare data to compare survival in older MCL patients who began chemotherapy with or without rituximab within 180 days of diagnosis. Patients were followed from diagnosis (January 1999 to December 2005) until death or the end of observation (December 2007). Medicare administrative and claims data were used to identify the date and cause of death and the immunochemotherapy regimen. Of 638 patients, the mean age at diagnosis was 75 years, 75% had stage III/IV disease, 67% had extranodal involvement, and 64% received rituximab. The average length of first-line treatment was 21 weeks, with no difference between the 2 groups (P = .76). Median survival was 27 months for chemotherapy alone, compared with 37 months for chemotherapy plus rituximab (P 〈 .001). In multivariate analysis of 2-year survival, rituximab plus chemotherapy was associated with lower all-cause (hazard ratio [HR] 0.58; 95% confidence interval [CI] 0.41-0.82; P 〈 .01), and cancer-specific (HR 0.56; 95% CI 0.37-0.84; P 〈 .01) mortality. Results were similar when using the entire observation period, propensity score analysis, and limiting chemotherapy to CHOP/CHOP-like. We conclude that first-line chemotherapy including rituximab is associated with significantly improved survival in older patients diagnosed with MCL.

Description: This study shows that human postthymic T cells express CD10 when undergoing apoptosis, irrespective of the signal responsible for initiating the apoptotic process. Cells from continuous T-cell lines did not normally express CD10, but became CD10+ when induced into apoptosis by human immunodeficiency virus (HIV) infection and exposure to CD95 monoclonal antibody, etoposide, or staurosporin. Inhibitors of caspases blocked apoptosis and CD10 expression. Both CD4+ and CD8+ T cells purified from normal peripheral blood expressed CD10 on apoptotic induction. CD10 was newly synthesized by the apoptosing cells because its expression was inhibited by exposure to cycloheximide and CD10 mRNA became detectable by reverse transcription-polymerase chain reaction in T cells cultured under conditions favoring apoptosis. To show CD10 on T cells apoptosing in vivo, lymph node and peripheral blood T cells from HIV+ subjects were used. These suspensions were composed of a substantial, although variable, proportion of apoptosing T cells that consistently expressed CD10. In contrast, CD10+ as well as spontaneously apoptosing T cells were virtually absent in peripheral blood from normal individuals. Collectively, these observations indicate that CD10 may represent a reliable marker for identifying and isolating apoptosing T cells in vitro and ex vivo and possibly suggest novel functions for surface CD10 in the apoptotic process of lymphoid cells.

Description: Abstract 4127 In the age of novel targeted agents, autologous stem cell transplant (ASCT) remains the standard of care for younger patients with newly diagnosed multiple myeloma (MM), offering similar treatment responses and overall survivals as standard chemotherapeutic agents but with the added benefit of a prolonged treatment-free period. Nevertheless, a standard of care for stem cell mobilization for ASCT has yet to be determined. Even in the era of new mobilization agents such as Plerixafor, Cyclophosphamide (Cy) and G-CSF combination remains the preferred mobilizing approach for patients with MM. Several studies have shown that Cy improves the stem cell yield at the expense of increased toxicity, but whether the administration of this chemotherapeutic agent pre-transplant has any impact on the long-term event-free and/or overall survival of myeloma patients remains controversial. In this study, we present a retrospective analysis of 186 patients with newly diagnosed MM who underwent ASCT with high-dose melphalan 200 mg/m2 (HDM) between December of 2000 and 2008 at our Institution. Eighty-three patients were mobilized with single agent G-CSF and 103 patients received high dose Cy (4 gm/m2) and G-CSF combination. Patient characteristics were similar between the treatment groups, including: age, gender, disease stage, and disease status prior to transplant. However, toxicity post-mobilization with Cy/G-CSF was significantly higher compared with G-SCF alone, including: febrile neutropenia (23%), hemorrhagic cystitis (8%), GI toxicity (57%), re-hospitalization due to complications and transplant delay (14%). The overall post-transplant toxicity was similar in the 2 groups, though the treatment related mortality was slightly higher in the Cy/G-CSF arm (4% versus 2%). Post transplant responses were not significantly different in the 2 groups, with 60% of patients achieving a VGPR or better after ASCT in the G-CSF group and 49% in the Cy/G-CSF group (p = 0.33). The median event-free survivals (EFS) for the Cy/G-CSF and G-CSF cohorts were 21.6 and 22.6 months, respectively, (p = 0.62) yielding no significant difference (Figure 1). Similarly, with a median follow up for surviving patients of 34.3 and 32.7 months, the median overall survivals were 68.2 and 62.3 months (p = 0.23) for the Cy/G-CSF and G-CSF cohorts, respectively (Figure 2). This retrospective analysis confirms that the addition of high dose Cy as part of the mobilizing regimen offers no improvement on the transplant outcome for patients with newly diagnosed myeloma and should therefore only be used in cases of difficult stem cell mobilization. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 1753 Background: Ruxolitinib (INC424), a potent and selective oral JAK1 and JAK2 inhibitor, has demonstrated rapid and durable reductions in splenomegaly and improved disease-related symptoms, role functioning, and quality of life (QoL) in 2 phase 3 studies in patients with myelofibrosis (MF) (the COMFORT studies). These studies compared ruxolitinib with either placebo or best available therapy (BAT). This analysis compares the efficacy outcomes between the placebo arm from COMFORT-I and the BAT arm from COMFORT-II. Methods: COMFORT-I is a randomized (1:1), double-blind, multicenter study comparing ruxolitinib 15 or 20 mg twice daily (bid) with placebo, and COMFORT-II is a randomized (2:1), open-label, multicenter study comparing ruxolitinib 15 or 20 mg bid with BAT (investigator-selected therapy, including no treatment). Both studies met their primary end points with statistical significance (ruxolitinib vs control): the percentage of patients achieving ≥35% reduction in spleen volume at week 24 (COMFORT-I, P

Description: The outcome of patients with non-Hodgkin’s lymphoma has been improved by current approaches to treatment. Nevertheless, many patients either do not have a complete remission or ultimately relapse. To identify such patients, it is important to be able to predict the outcome. We previously found that the differentiation inhibitory factor/nm23 was correlated with the prognosis of acute myeloid leukemia. To examine the prognostic effect of nm23 on non-Hodgkin’s lymphoma, we established an enzyme-linked immunosorbent assay procedure to determine nm23-H1 protein levels in plasma and assessed the association of this protein level with the response to chemotherapy, overall survival, and progression-free survival in patients with aggressive non-Hodgkin’s lymphoma. The plasma concentration of nm23-H1 was significantly higher in patients with malignant lymphoma than in normal controls, especially in aggressive non-Hodgkin’s lymphoma. The complete remission rate in patients with higher nm23-H1 levels was significantly worse than that in patients with lower nm23-H1 levels. Overall survival and progression-free survival were also lower in patients with higher nm23-H1 levels than in those with lower levels. The 3-year survival rates in patients with low and high nm23-H1levels were 79.5% and 6.7% (P = .0001). A multivariate analysis of prognostic factors showed that the plasma nm23-H1level was independently associated with the survival and progression-free survival. An elevated plasma nm23-H1concentration predicts a poor outcome of advanced non-Hodgkin’s lymphoma. Therefore, nm23-H1 in plasma may be useful for identifying a distinct group of patients at very high risk.

Description: Abstract 1768 B-cell chronic lymphocytic leukemia (CLL) is characterized by deregulated expression of microRNAs (miRNAs). These post-transcriptional regulators of gene expression play a crucial role in controlling multiple cellular processes. By microarray analysis and quantitative RT-PCR we observed significantly lower levels of miR-126, miR-130a, miR-143, miR-181a and miR-326 in primary CLL cells compared to normal B cells. Transfection of synthetic miR-130a or miR-143 induced a significant reduction in cell viability of both primary CLL cells and the CLL cell line MEC-1. As autophagy is connected to cancer cell survival and resistance to apoptosis, we investigated the effect of these two miRNAs on autophagy by following the specific autophagosome marker LC3 (microtubule-associated protein 1 light chain 3). Therefore, we generated MEC-1 cells stably expressing GFP-tagged LC3 and analyzed autophagosome formation by using an imaging flow cytometer quantifying GFP-positive dots. These experiments revealed that autophagy is induced in these cells upon starvation, and that introduction of miR-130a, but not miR-143, resulted in a reduction of autophagosome formation (see Figure). These findings were verified by LC3 Western blot analysis, and extended to primary CLL cells, showing for the first time that autophagy is an active process in these cells and that miR-130a inhibits autophagy in primary CLL cells as well. To further elucidate the molecular mechanism of miR-130a-mediated CLL cell survival and autophagy, we aimed at identifying putative target genes of this miRNA and identified ATG2B, an autophagy-related gene, as well as DICER1 and AGO4, two components of the miRNA processing machinery, as direct target genes of miR-130a in CLL cells. The relevance and role of these three novel target genes in miR-130a-regulated cell death/cell survival programs is under current investigation. Figure: Analysis of autophagy using MEC-1 cell line stably expressing GFP-tagged LC3 protein. Green dots representing autophagosomes were quantified in MEC-1/GFP-LC3 cells under starvation by imaging flow cytometry (Image Stream, Amnis). Transfection with synthetic miR-130a reduced the autophagic flux in these cells compared to scrambled negative control miRNA (NC). Figure:. Analysis of autophagy using MEC-1 cell line stably expressing GFP-tagged LC3 protein. Green dots representing autophagosomes were quantified in MEC-1/GFP-LC3 cells under starvation by imaging flow cytometry (Image Stream, Amnis). Transfection with synthetic miR-130a reduced the autophagic flux in these cells compared to scrambled negative control miRNA (NC). Disclosures: No relevant conflicts of interest to declare.

Description: The Blood and Marrow Transplant Clinical Trials Network conducted 2 parallel multicenter phase 2 trials for individuals with leukemia or lymphoma and no suitable related donor. Reduced intensity conditioning (RIC) was used with either unrelated double umbilical cord blood (dUCB) or HLA-haploidentical related donor bone marrow (Haplo-marrow) transplantation. For both trials, the transplantation conditioning regimen incorporated cyclophosphamide, fludarabine, and 200 cGy of total body irradiation. The 1-year probabilities of overall and progression-free survival were 54% and 46%, respectively, after dUCB transplantation (n = 50) and 62% and 48%, respectively, after Haplo-marrow transplantation (n = 50). The day +56 cumulative incidence of neutrophil recovery was 94% after dUCB and 96% after Haplo-marrow transplantation. The 100-day cumulative incidence of grade II-IV acute GVHD was 40% after dUCB and 32% after Haplo-marrow transplantation. The 1-year cumulative incidences of nonrelapse mortality and relapse after dUCB transplantation were 24% and 31%, respectively, with corresponding results of 7% and 45%, respectively, after Haplo-marrow transplantation. These multicenter studies confirm the utility of dUCB and Haplo-marrow as alternative donor sources and set the stage for a multicenter randomized clinical trial to assess the relative efficacy of these 2 strategies. The trials are registered at www.clinicaltrials.gov under NCT00864227 (BMT CTN 0604) and NCT00849147 (BMT CTN 0603).

Description: Recently, we have demonstrated that antibodies that block the function of the β2-integrin leukocyte function-associated antigen-1 (LFA-1) completely abrogate the rapid mobilization of hematopoietic progenitor cells (HPC) with colony-forming and radioprotective capacity induced by interleukin-8 (IL-8) in mice. These findings suggested a direct inhibitory effect of these antibodies on LFA-1–mediated transmigration of stem cells through the bone marrow endothelium. Therefore, we studied the expression and functional role of LFA-1 on murine HPC in vitro and in vivo. In steady state bone marrow ± 50% of the mononuclear cells (MNC) were LFA-1neg. Cultures of sorted cells, supplemented with granulocyte colony-stimulating factor (G-CSF)/granulocyte-macrophage colony-stimulating factor (GM-CSF)/IL-1/IL-3/IL-6/stem cell factor (SCF) and erythropoietin (EPO) indicated that the LFA-1neg fraction contained the majority of the colony-forming cells (CFCs) (LFA-1neg 183 ± 62/7,500 cells v LFA-1pos 29 ± 17/7,500 cells,P 〈 .001). We found that the radioprotective capacity resided almost exclusively in the LFA-1neg cell fraction, the radioprotection rate after transplantation of 103, 3 × 103, 104, and 3 × 104 cells being 63%, 90%, 100%, and 100% respectively. Hardly any radioprotection was obtained from LFA-1pos cells. Similarly, in cytokine (IL-8 and G-CSF)–mobilized blood, the LFA-1neg fraction, which comprised 5% to 10% of the MNC, contained the majority of the colony-forming cells, as well as almost all cells with radioprotective capacity. Subsequently, primitive bone marrow-derived HPC, represented by Wheat-germ-agglutinin (WGA)+/Lineage (Lin)−/Rhodamine (Rho)− sorted cells, were examined. More than 95% of the Rho− cells were LFA-1neg. Cultures of sorted cells showed that the LFA-1neg fraction contained all CFU. Transplantation of 150 Rho− LFA-1neg or up to 600 Rho−LFA-1pos cells protected 100% and 0% of lethally irradiated recipient mice, respectively. These results show that primitive murine HPC in steady-state bone marrow and of cytokine-mobilized blood do not express LFA-1.

Description: Various combinations of antibodies directed to cell surface markers have been used to isolate human and rhesus macaque hematopoietic stem cells (HSCs). These protocols result in poor enrichment or require multiple complex steps. Recently, a simple phenotype for HSCs based on cell surface markers from the signaling lymphocyte activation molecule (SLAM) family of receptors has been reported in the mouse. We examined the possibility of using the SLAM markers to facilitate the isolation of highly enriched populations of HSCs in humans and rhesus macaques. We isolated SLAM (CD150+CD48−) and non-SLAM (not CD150+CD48−) cells from human umbilical cord blood CD34+ cells as well as from human and rhesus macaque mobilized peripheral blood CD34+ cells and compared their ability to form colonies in vitro and reconstitute immune-deficient (nonobese diabetic/severe combined immunodeficiency/interleukin-2 γc receptornull, NSG) mice. We found that the CD34+ SLAM population contributed equally or less to colony formation in vitro and to long-term reconstitution in NSG mice compared with the CD34+ non-SLAM population. Thus, SLAM family markers do not permit the same degree of HSC enrichment in humans and rhesus macaques as in mice.

Description: T-cell therapy with genetically modified T cells targeting CD19 or CD20 holds promise for the immunotherapy of hematologic malignancies. These targets, however, are only present on B cell–derived malignancies, and because they are broadly expressed in the hematopoietic system, their targeting may have unwanted consequences. To expand T-cell therapies to hematologic malignancies that are not B cell–derived, we determined whether T cells can be redirected to CD70, an antigen expressed by limited subsets of normal lymphocytes and dendritic cells, but aberrantly expressed by a broad range of hematologic malignancies and some solid tumors. To generate CD70-specific T cells, we constructed a chimeric antigen receptor (CAR) consisting of the CD70 receptor (CD27) fused to the CD3-ζ chain. Stimulation of T cells expressing CD70-specific CARs resulted in CD27 costimulation and recognition of CD70-positive tumor cell lines and primary tumor cells, as shown by IFN-γ and IL-2 secretion and by tumor cell killing. Adoptively transferred CD70-specific T cells induced sustained regression of established murine xenografts. Therefore, CD70-specific T cells may be a promising immunotherapeutic approach for CD70-positive malignancies.

Description: Thrombomodulin (TM) is a widely expressed glycoprotein receptor that plays a physiologically important role in maintaining normal hemostatic balance postnatally. Inactivation of the TM gene in mice results in embryonic lethality without thrombosis, suggesting that structures of TM not recognized to be involved in coagulation might be critical for normal fetal development. Therefore, the in vivo role of the cytoplasmic domain of TM was studied by using homologous recombination in ES cells to create mice that lack this region of TM (TMcyt/cyt). Cross-breeding of F1 TMwt/cyt mice (1 wild-type and 1 mutant allele) resulted in more than 300 healthy offspring with a normal Mendelian inheritance pattern of 25.7% TMwt/wt, 46.6% TMwt/cyt, and 27.7% TMcyt/cyt mice, indicating that the tail of TM is not necessary for normal fetal development. Phenotypic analyses showed that the TMcyt/cyt mice responded identically to their wild-type littermates after procoagulant, proinflammatory, and skin wound challenges. Plasma levels of plasminogen, plasminogen activator inhibitor 1 (PAI-1), and 2-antiplasmin were unaltered, but plasmin:2-antiplasmin (PAP) levels were significantly lower in TMcyt/cyt mice than in TMwt/wt mice (0.46 ± 0.2 and 1.99 ± 0.1 ng/mL, respectively; P 〈 .001). Tissue levels of TM antigen were also unaffected. However, functional levels of plasma TM in the TMcyt/cyt mice, as measured by thrombin-dependent activation of protein C, were significantly increased (P 〈 .001). This supported the hypothesis that suppression in PAP levels may be due to augmented activation of thrombin-activatable fibrinolysis inhibitor (TAFI), with resultant inhibition of plasmin generation. In conclusion, these studies exclude the cytoplasmic domain of TM from playing a role in the early embryonic lethality of TM-null mice and support its function in regulating plasmin generation in plasma.

Description: Abstract 2542 Background: Patients with high-risk chronic lymphocytic leukemia (CLL) uniformly relapse after conventional chemo-immunotherapy, but roughly half achieve long-term disease-free survival (DFS) following allogeneic hematopoietic cell transplantation (allo-HCT). Quantification of minimal residual disease (MRD) following allo-HCT predicts post-transplant relapse (PTR) when CLL disease burden remains greater than 10e-4 (ie, 1 leukemic cell in 10,000 peripheral blood mononuclear cells [PBMC]) when quantified by allele-specific oligonucleotide quantitative polymerase chain reaction (ASO-PCR) or flow cytometry. We previously demonstrated the feasibility of MRD quantification using consensus primers to amplify all immunoglobulin heavy chain (IGH) genes in a mixture of PBMC, followed by high-throughput sequencing (HTS) and clonotypic quantification. In our prior work, we used 454 pyrosequencing technology which enabled 10e-5 sensitivity. Here, we report 10e-6 MRD sensitivity using novel Illumina-based HTS that provides better prediction of disease recurrence than ASO-PCR. Methods: We amplified IGH loci from genomic DNA extracted from PBMC (median input 2.4×10e6 cells; range 1.1–23.7×10e6) using V and J segment consensus primers. Amplified IGH molecules were then sequenced with one million or more dedicated reads using Illumina HiSeq and clones were quantified using Sequenta HTS bioinformatics. To verify 10e-6 sensitivity using this system, a clonal B cell population was diluted to 10e-6 in PBMC from a healthy donor with successful clonal detection. Disease-bearing samples (either pre-treatment or after PTR) were sequenced to verify applicability of consensus primers for each patient and to determine each patient's unique clonal IGH sequence. Thirty-seven PBMC samples from 14 patients which were either negative (n=30) by ASO-PCR or detectable below the linear limit of detection (n=7) were subjected to MRD quantification by HTS. The integrity of all samples was determined by preliminary IGH quantitative PCR. Results: CLL-specific IGH clonotypes from all 14 patients amplified successfully from samples with known disease burden, confirming the acceptability of consensus primers for all patients. Concordant MRD negativity by ASO-PCR and IGH-HTS was only observed in 14/37 samples (38%), while 16 samples (43%) were negative by ASO-PCR but detectable at the 10e-6 level using IGH-HTS (range 0.1–11 CLL IGH sequences per 10e6 PBMC genomes). Two of 37 samples (5%) exhibited concordant low-level positivity in the 10e-5 range. 4/37 samples (11%) were concordantly positive, but quantified more than or equal to 0.5log higher with ASO-PCR than HTS. One sample was positive below the linear limit of detection by ASO-PCR but negative by HTS. With median clinical follow-up of 1072 days (range 522–1986 days), one of 7 patients (14%) who exhibited MRD negativity by both ASO-PCR and IGH-HTS relapsed. All 5 patients found to have MRD negativity by ASO-PCR with concurrent MRD positivity using IGH-HTS relapsed. The association between IGH-HTS negativity and long-term DFS was highly significant (p=0.005), whereas ASO-PCR negativity was not significantly associated with DFS (p=0.47). In patients found to be MRD negative by ASO-PCR but positive by IGH-HTS, the HTS result predicted clinical relapse by a median 321 days (range 38–644 days). Conclusions: Massively parallel immunoglobulin gene sequencing using Illumina HiSeq provides a heretofore unachievable level of MRD sensitivity in peripheral blood samples from patients with CLL. Samples found to be negative or below the linear limits of detection for CLL MRD using ASO-PCR were more accurately quantified using IGH-HTS. Quantification of CLL MRD using IGH-HTS has tremendous prognostic value since achievement of MRD negativity with 10e-6 sensitivity is highly associated with long-term DFS. To further validate the performance of Illumina-based HTS, we are currently sequencing 289 archived post-transplant PBMC from 42 CLL patients. This scalable and cost-effective platform for ultra-sensitive MRD quantification using consensus primers will broadly expand the availability and utility of post-transplant MRD assessment. Disclosures: Faham: Sequenta, Inc.: Employment, Equity Ownership. Carlton:Sequenta, Inc.: Employment, Equity Ownership. Zheng:Sequenta, Inc.: Employment, Equity Ownership. Moorhead:Sequenta, Inc.: Employment, Equity Ownership. Willis:Sequenta, Inc.: Employment, Equity Ownership.

Description: The anti-CD20 mAb rituximab has substantially improved the clinical outcome of patients with a wide range of B-cell malignancies. However, many patients relapse or fail to respond to rituximab, and thus there is intense investigation into the development of novel anti-CD20 mAbs with improved therapeutic efficacy. Although Fc-FcγR interactions appear to underlie much of the therapeutic success with rituximab, certain type II anti-CD20 mAbs efficiently induce programmed cell death (PCD), whereas rituximab-like type I anti-CD20 mAbs do not. Here, we show that the humanized, glycoengineered anti-CD20 mAb GA101 and derivatives harboring non-glycoengineered Fc regions are type II mAb that trigger nonapoptotic PCD in a range of B-lymphoma cell lines and primary B-cell malignancies. We demonstrate that GA101-induced cell death is dependent on actin reorganization, can be abrogated by inhibitors of actin polymerization, and is independent of BCL-2 overexpression and caspase activation. GA101-induced PCD is executed by lysosomes which disperse their contents into the cytoplasm and surrounding environment. Taken together, these findings reveal that GA101 is able to potently elicit actin-dependent, lysosomal cell death, which may potentially lead to improved clearance of B-cell malignancies in vivo.

Description: The natural history of chronic hepatitis C (HCV) infections in long-term leukemia survivors has not been well characterized. We studied the prevalence of HCV infections, measured HCV RNA levels, and evaluated the severity of liver disease in patients with leukemia who achieved long-term remissions after intensive chemotherapy or bone marrow transplantation (BMT). HCV antibody tests were performed by the enzyme-linked immunosorbent assay (ELISA) and positive tests confirmed by the recombinant immunoblot assay (RIBA). HCV RNA levels were measured by the branched DNA (bDNA) assay. Seventy-five leukemia survivors with 25 or more blood donor exposures were identified. Nine (12%) were anti-HCV positive. All were infected before 1992 when second generation HCV screening tests were implemented. Mean HCV RNA levels were 10.3 ×106 eq/mL versus 3.2 × 106 eq/mL (P = .056) in a control group of 20 anti-HCV positive immunocompetent individuals of comparable age who were infected twice as long (17.8 ± 6.5 years v 9.0 ± 4.4 years in leukemia survivors, P = .001). Liver biopsies were performed on six of the nine anti-HCV positive leukemia survivors. All showed at least moderate portal inflammation and half had evidence of bridging fibrosis. We conclude that viral loads in anti-HCV positive leukemia survivors are markedly higher than in immunocompetent controls. Our results suggest that long-term leukemia survivors with chronic HCV may have more rapidly progressive liver disease than has been previously recognized.

Description: Although sickle cell disease (SCD) has a variable clinical course, many patients develop end-organ complications that are associated with significant morbidity and early mortality. Myeloablative allogeneic HSCT (allo-HSCT) is curative but has been historically performed only in children younger than 16 years of age. Modest modifications in the conditioning regimen and supportive care have improved outcome such that the majority of children with a suitable HLA-matched sibling donor can expect a cure from this approach. However, adult patients have been excluded from myeloablative allo-HSCT because of anticipated excess toxicity resulting from accumulated disease burden. Efforts to use nonmyeloablative transplantation strategies in adults logically followed but were initially met with largely disappointing results. Recent results, however, indicate that nonmyeloablative allo-HSCT in adult patients with SCD allows for stable mixed hematopoietic chimerism with associated full-donor erythroid engraftment and normalization of blood counts, and persistence in some without continued immunosuppression suggests immunologic tolerance. The attainment of tolerance should allow extension of these potentially curative approaches to alternative donor sources. Efforts to build on these experiences should increase the use of allo-HSCT in patients with SCD while minimizing morbidity and mortality.

Description: Abstract 2708 Background: The simplified Mantle Cell Lymphoma International Prognostic Index (MIPI) has been shown to be a good predictor of patient survival (Blood 2008;111:558–65; Blood 2010;115:1530–1533). This post hoc study analyzed data from a randomized, phase III clinical trial investigating temsirolimus (TEM) in relapsed/refractory mantle cell lymphoma (MCL) in which TEM 175/75 (175 mg for first 3 weeks then 75 mg weekly) demonstrated significantly longer progression-free survival (PFS) vs investigator's choice of therapy (INV; 4.8 vs 1.9 months, respectively; hazard ratio [HR]=0.44; P=.0009; J Clin Oncol 2009;27:3822–9). Patients receiving TEM 175/25 (175 mg for first 3 weeks then 25 mg weekly) also had longer PFS vs INV, but this difference was not significant (3.4 vs 1.9 months; respectively; HR=0.65; P=.06). During the trial, baseline prognostic risk classification was not recorded; thus, patients were retrospectively assigned baseline prognostic scores, and outcomes were analyzed according to risk category. Methods: All patients (N=162) were classified as low, intermediate, or high risk using the simplified MIPI. The MIPI scores were based on 4 independent prognostic markers: age, Eastern Cooperative Oncology Group (ECOG) performance status, lactate dehydrogenase level, and white blood cell count. Median PFS and overall survival (OS) were calculated using Kaplan-Meier estimates, and treatment effect was assessed using log-rank statistics. P values of ≤.05 indicated significance of the treatment effect between the 2 treatment groups. As the phase III study was not powered to analyze patients according to MIPI risk categorization, statistical analyses shown are for explanatory purposes. Results: Distribution was relatively even across MIPI risk categories (55 patients low, 59 patients intermediate, 48 patients high). MIPI distributions in the 2 TEM arms were: 175/75 (n=54: 28% low, 43% intermediate, 30% high); 175/25 (n=54: 28% low, 33% intermediate, 39% high). Relative to the TEM arms, the INV arm (n=54) had a higher proportion of low-risk patients (46% low; 33% intermediate; 20% high). TEM 175/75 resulted in significant improvement in median PFS (independent assessment) vs INV in high-risk patients (P=.003) (Table); trends toward improvement were observed for intermediate-risk and low-risk patients (P=.06 in each group). By investigator assessment, TEM 175/75 improved median PFS vs INV by 7.9 months in the low-risk category (P=.0007) and by 2.8 months (P=.06) and 1.1 month (P=.001) in the intermediate-risk and high-risk categories, respectively. A trend toward longer OS was observed in the low-risk patients treated with TEM 175/75 vs INV (P=.0502). In the low-risk category, maintenance of stable disease or better response was achieved in more patients receiving TEM 175/75 (9/15 [60%]) vs INV (5/25 [20%]); objective responses were observed in 5 patients with TEM 175/75 and in no patients with INV. Patients in the low-risk category treated with TEM 175/75 received a longer duration of therapy vs INV (30.7 vs 9.0 wk, respectively). Across the duration of treatment, the average frequency of delay was once per 5.6 wk with TEM 175/75 vs once per 6.4 wk with INV. TEM was generally well tolerated. Grade 3/4 anemia, thrombocytopenia, and infection also were analyzed by patient risk category. In both the TEM 175/75 and INV groups, the selected grade 3/4 events occurred more commonly in high-risk than low-risk patients. In the low-risk category, a higher incidence of grade 3/4 thrombocytopenia and anemia was observed with TEM 175/75 vs INV. Conclusions: Retrospective risk analysis of patients according to the simplified MIPI demonstrated that TEM 175/75 was effective across patient risk categories. The greatest benefit trend was observed in low-risk patients. In this study of relapsed/refractory MCL patients, MIPI was a good predictor of survival outcome. Disclosures: Hess: Pfizer: Consultancy, Honoraria, Research Funding. Off Label Use: Torisel is licensed for treatment of relapsed and/or refractory mantle cell lymphoma and renal cell carcinoma in Europe. Torisel is licensed in the US for renal cell carcinoma. Kang:Pfizer: Employment. Moran:Pfizer: Employment.

Description: A long outstanding problem is the resolution of the full potential of hematopoietic precursors. The commonly used allotypic marker Ly5 permits the tracing of lymphoid and granulocyte-macrophage (GM) output. Here we present a novel eGFP allele that allows the quantitative analysis of red blood cell (RBC) origin at the single-cell level. The miR-144/451 locus is required for erythroid development and homeostasis. Taking advantage of the fact that miR-451 is specifically and highly expressed in the erythroid lineage, we inserted an eGFP expression cassette into the miR-144/451 locus. In miR-144/451+/eGFP animals, accumulation of eGFP is exclusively observed during terminal erythroid differentiation. Expression of miR-144/451eGFP ignites immediately before the CFU-E stage and results in strong and complete labeling of all mature RBCs in circulation. Using competitive reconstitution experiments in the Ly5 transplant model, we show that eGFP linearly correlates with Ly5 expression. Thus, the miR-144/451eGFP allele represents a novel tool for the resolution of erythroid potential.

Description: A 250-cGy whole-body γ-radiation dose was used to induce thymus regression in mice, and to study the expression and function of extracellular matrix (ECM) receptors in distinct thymocyte subsets emerging during repopulation of the organ. The onset of regeneration was detected from day 2 to 3 postirradiation (P-Ir), when a remarkable increase in the absolute counts of CD3−CD25hiCD44+ and CD3−CD25in/hiCD44−cells occurred. Enhanced expression of L-selectin, 4, and 5 integrin chains (L-selhi 4hi5hi) was also exhibited by these cells. This pattern of expression was maintained until the CD4+CD8+ (DP) young stage was achieved. Afterward, there was a general downregulation of these ECM receptors in DP as well as in CD4+ or CD8+ single positive (SP) thymocytes (L-selin 4in5in). In some recently generated SP cells, 4 expression was downregulated before the 5 chain, and L-selectin was upregulated in half of more mature cells. The expression of the 6 integrin chain was downregulated only in maturing CD4+cells. Importantly, the increased expression of L-selectin and 4 and 5 chains in thymocytes was strongly correlated with their adhesiveness to thymic epithelial cells (TEC) in vitro. Blocking experiments with monoclonal antibody or peptides showed the following: (1) that the LDV rather than the REDV cell attachment motif in the IIIC segment of fibronectin is targeted by the 4 integrin during thymocyte/TEC adhesion; (2) that the RGD motif of the 120-kD fragment of fibronectin, a target for 5 integrin, has a secondary role in this adhesion; and (3) that the YIGSR cell attachment motif of the β1 chain of laminin/merosin recognized by a nonintegrin receptor is not used for thymocyte adherence. In conclusion, our results show that an upregulated set of receptors endows CD25+ precursors and cells up to the young DP stage with a high capability of interacting with thymic ECM components.

Description: Thymic negative selection renders the developing T-cell repertoire tolerant to self-major histocompatability complex (MHC)/peptide ligands. The major mechanism of induction of self-tolerance is thought to be thymic clonal deletion, ie, the induction of apoptotic cell death in thymocytes expressing a self-reactive T-cell receptor. Consistent with this hypothesis, in mice deficient in thymic clonal deletion mediated by cells of hematopoietic origin, a twofold to threefold increased generation of mature thymocytes has been observed. Here we describe the analysis of the specificity of T lymphocytes developing in the absence of clonal deletion mediated by hematopoietic cells. In vitro, targets expressing syngeneic MHC were readily lysed by activated CD8+ T cells from deletion-deficient mice. However, proliferative responses of T cells from these mice on activation with syngeneic antigen presenting cells were rather poor. In vivo, deletion-deficient T cells were incapable of induction of lethal graft-versus-host disease in syngeneic hosts. These data indicate that in the absence of thymic deletion mediated by hematopoietic cells functional T-cell tolerance can be induced by nonhematopoietic cells in the thymus. Moreover, our results emphasize the redundancy in thymic negative selection mechanisms.

Description: A variety of previously published studies have shown the presence of autoantibodies directed against oncogenic proteins in the sera of patients with tumors. Generally the underlying genetic aberration responsible for the induction of an immune response directed against an abnormal protein is unknown. In our studies we analyzed the role of gene amplification in the production of autoantibodies in squamous cell lung carcinoma. We screened a cDNA expression library with autologous patient serum and characterized the isolated cDNA clones encoding tumor expressed antigens termed LCEA (lung carcinoma expressed antigens). As determined by sequence analysis, the 35 identified cDNA clones represent 19 different genes of both known and unknown function. The spectrum of different clones were mapped by polymerase chain reaction (PCR) and fluorescence in-situ hybridization, showing that a majority are located on chromosome 3, which is frequently affected by chromosomal abnormalities in lung cancer. Gene amplification of 14 genes was analyzed by comparative PCR. Nine genes (65% of all analyzed genes) were found to be amplified; furthermore, most of them are also overrepresented in the pool of cDNA clones, suggesting an overexpression in the corresponding tumor. These results strongly suggest that gene amplification is one possible mechanism for the expression of immunoreactive antigens in squamous cell lung carcinoma.

Description: CD36 modulates platelet function via binding to oxidized LDL (oxLDL), cell-derived microparticles, and thrombospondin-1. We hypothesized that the level of platelet CD36 expression may be associated with inheritance of specific genetic polymorphisms and that this would determine platelet reactivity to oxLDL. Analysis of more than 500 subjects revealed that CD36 expression levels were consistent in individual donors over time but varied widely among donors (200-14 000 molecules per platelet). Platelet aggregometry and flow cytometry in a subset of subjects with various CD36 expression levels revealed a high level of correlation (r2 = 0.87) between platelet activation responses to oxLDL and level of CD36 expression. A genome-wide association study of 374 white subjects from the Cleveland Clinic ASCLOGEN study showed strong associations of single nucleotide polymorphisms in CD36 with platelet surface CD36 expression. Most of these findings were replicated in a smaller subset of 25 black subjects. An innovative gene-based genome-wide scan provided further evidence that single nucleotide polymorphisms in CD36 were strongly associated with CD36 expression. These studies show that CD36 expression on platelets varies widely, correlates with functional responses to oxLDL, and is associated with inheritance of specific CD36 genetic polymorphisms, and suggest that inheritance of specific CD36 polymorphisms could affect thrombotic risk.

Description: Human erythroid precursors grown in culture possess membrane receptors that bind and internalize acid isoferritin. These receptors are regulated by the iron status of the cell, implying that ferritin iron uptake may represent a normal physiologic pathway. The present studies describe the fate of internalized ferritin, the mechanisms involved in the release of its iron, and the recognition of this iron by the cell. Normal human erythroid precursors were grown in a 2-phase liquid culture that supports the proliferation, differentiation, and maturation of erythroid precursors. At the stage of polychromatic normoblasts, cells were briefly incubated with 59Fe- and/or125I-labeled acid isoferritin and chased. The125I-labeled ferritin protein was rapidly degraded and only 50% of the label remained in intact ferritin protein after 3 to 4 hours. In parallel, 59Fe decreased in ferritin and increased in hemoglobin. Extracellular holoferritin uptake elevated the cellular labile iron pool (LIP) and reduced iron regulatory protein (IRP) activity; this was inhibited by leupeptin or chloroquine. Extracellular apoferritin taken up by the cell functioned as an iron scavenger: it decreased the level of cellular LIP and increased IRP activity. We suggest that the iron from extracellular is metabolized in a similar fashion by developing erythroid cells as is intracellular ferritin. Following its uptake, extracellular ferritin iron is released by proteolytic degradation of the protein shell in an acid compartment. The released iron induces an increase in the cellular LIP and participates in heme synthesis and in intracellular iron regulatory pathways.

Description: A multifaceted immunotherapeutic strategy that includes hematopoietic stem cell (HSC) transplantation, T-cell adoptive transfer, and tumor vaccination can effectively eliminate established neuroblastoma tumors in mice. In vivo depletion of CD4+ T cells in HSC transplantation recipients results in increased antitumor immunity when adoptively transferred T cells are presensitized, but development of T-cell memory is severely compromised. Because increased percentages of regulatory T (Treg) cells are seen in HSC transplantation recipients, here we hypothesized that the inhibitory effect of CD4+ T cells is primarily because of the presence of expanded Treg cells. Remarkably, adoptive transfer of presensitized CD25-depleted T cells increased tumor vaccine efficacy. The enhanced antitumor effect achieved by ex vivo depletion of CD25+ Treg cells was similar to that achieved by in vivo depletion of all CD4+ T cells. Depletion of CD25+ Treg cells resulted in elevated frequencies of tumor-reactive CD8 and CD4+ T cells and increased CD8-to-Treg cell ratios inside tumor masses. All mice given presensitized CD25-depleted T cells survived a tumor rechallenge, indicating the development of long-term CD8+ T-cell memory to tumor antigens. These observations should aid in the future design of immunotherapeutic approaches that promote the generation of both acute and long-term antitumor immunity.

Description: The microvasculature assumes an inflammatory and procoagulant state in a variety of different diseases, including sickle cell disease (SCD), which may contribute to the high incidence of ischemic stroke in these patients. This study provides evidence for accelerated thrombus formation in arterioles and venules in the cerebral vasculature of mice that express hemoglobin-S (βs mice). Enhanced microvascular thrombosis in βs mice was blunted by immunologic or genetic interventions that target tissue factor, endothelial protein C receptor, activated protein C, or thrombin. Platelets from βs mice also exhibited enhanced aggregation velocity after stimulation with thrombin but not ADP. Neutropenia also protected against the enhanced thrombosis response in βs mice. These results indicate that the cerebral microvasculature is rendered vulnerable to thrombus formation in βs mice via a neutrophil-dependent mechanism that is associated with an increased formation of and enhanced platelet sensitivity to thrombin.

Description: Megakaryocytes transfer a diverse and functional transcriptome to platelets during the final stages of thrombopoiesis. In platelets, these transcripts reflect the expression of their corresponding proteins and, in some cases, serve as a template for translation. It is not known, however, if megakaryocytes differentially sort mRNAs into platelets. Given their critical role in vascular remodeling and inflammation, we determined whether megakaryocytes selectively dispense transcripts for matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) into platelets. Next-generation sequencing (RNA-Seq) revealed that megakaryocytes express mRNA for 10 of the 24 human MMP family members. mRNA for all of these MMPs are present in platelets with the exception of MMP-2, 14, and 15. Megakaryocytes and platelets also express mRNA for TIMPs 1-3, but not TIMP-4. mRNA expression patterns predicted the presence and, in most cases, the abundance of each corresponding protein. Nonetheless, exceptions were observed: MMP-2 protein is present in platelets but not its transcript. In contrast, quiescent platelets express TIMP-2 mRNA but only traces of TIMP-2 protein. In response to activating signals, however, platelets synthesize significant amounts of TIMP-2 protein. These results demonstrate that megakaryocytes differentially express mRNAs for MMPs and TIMPs and selectively transfer a subset of these into platelets. Among the platelet messages, TIMP-2 serves as a template for signal-dependent translation.

Description: Abstract 794FN2 LBH589 is a novel pan-deacetylase inhibitor (DACi) that has demonstrated clinical activity in phase I/II studies in patients with a variety of hematologic malignancies. Our group has previously presented preliminary results of a phase I study of LBH589 in patients with myelofibrosis (MF) (Mascarenhas et al, ASH 2009, a308) while a phase II trial using higher doses of LBH589 has also been reported (DeAngelo et al, ASH 2010,a630). Both studies identified reversible thrombocytopenia as the DLT and reported evidence of clinical responses. The final results of our phase I study and the effects of extended treatment with LBH589 are reported here. We enrolled 18 patients at 3 dose levels. Fifty-five percent of these patients had PMF, 28% Post-PV MF and 17% Post ET MF; all were intermediate/high risk based on Lille classification. Twenty-five mg PO TIW was determined to be the recommended phase II dose. All patients experienced resolution of their systemic symptoms and 10/11 patients with baseline palpable splenomegaly, who were evaluable after 1 month of therapy, had a median reduction of 30%, range 0–100%. Five patients entered into an extension phase of the trial and received 〉 6 months of therapy with a mean dose of 20mg PO TIW at time of optimal response (Table 1). Of these patients, 2 were initially enrolled in the 20 mg PO TIW cohort, 1 in the 30 mg PO TIW cohort and 2 in the 25 mg PO TIW cohort. Both patients at the lowest dose achieved clinical improvement (CI) by IWG-MRT response criteria at 6 months as did one patient at the 25 mg dose. The remaining 2 patients had SD at 30 and 25 mg. A mean reduction in palpable splenomegaly at 3 and 6 months of 55% and 83%, respectively, was observed in this group. Two of these patients had marked and durable improvement in anemia (patients 1 and 4). Patient 4 achieved a near CR at 16 months with resolution of palpable splenomegaly, elimination of peripheral blood dacrocytes and leukoerythroblastosis, a 4g/dL increase in hemoglobin, improvement in overall marrow cellularity and megakaryocyte atypia with an increase in erythroid precursors and a significant reduction of reticulin/collagen fibrosis. Patient 1 was heavily transfusion dependent requiring RBC transfusions weekly to maintain a mean hemoglobin of 6.5g/dL and after 6 months on LBH589 achieved 〉50% reduction in transfusion dependence maintaining a mean hemoglobin of 9g/dL. Patient 2 had resolution of palpable splenomegaly and leukoerythroblastosis by cycle 6 and the bone marrow at cycle 26 was characterized by a reduction in marrow fibrosis from grade 4 to 1. A phase II study is ongoing, 14 patients are currently enrolled, with a planned goal of 22 patients. Pharmacokinetic and pharmacodynamic studies as well as cytokine profiling of the phase I patients are being analyzed and will be presented at the meeting. We conclude that low doses of LBH589 delivered for greater than 6 months in patients with MF are capable of ameliorating symptoms, improving clinical features and reversing pathologic marrow changes. Disclosures: Off Label Use: Oral histone deacetylase inhibitor that targets epigenetic changes in malignant myelofibrosis cells with an goal to modify the disease process.

Description: Abstract 1506 BACKGROUND: A wide range of neuropsychological sequelae, noted in long-term survivors of ALL, have been in part ascribed to cranial irradiation (CRT), especially in children who are more vulnerable than adults. We had attempted to abandon prophylactic CRT by intensifying systemic chemotherapy and protracted triple IT (TIT) in ALL-02 trial; whereas one third of patients received CRT for CNS directed therapy in the former study (ALL-97). We present here the results of JACLS ALL-02 trials especially about the effect of the CNS-directed therapy. PATIENTS AND METHODS: Between 2002 and 2008, 1139 children with newly diagnosed non-T ALL with 1–18 years of age were enrolled to JACLS ALL-02 trial. Patients with Ph+ALL and T-ALL were registered to independent protocol. The criteria for diagnosis of CNS disease of the JACLS ALL-02 trial were defined as a CSF pleocytosis of 〉 5 cells /microL and the presence of recognizable blast cells on a well-stained cytospin preparation, or the presence of cranial-nerve palsies at a diagnosis of leukemia. Treatment group was divided into 3 groups according to the BFM-style initial prednisolone (PSL) response and the modified National Cancer Institute (NCI) workshop criteria. PSL good responders were divided into standard risk (SR) and high risk (HR) by WBC 10,000 and age 10. BCP-ALL with PSL poor responders and acute mixed lineage leukemia/ acute unclassified leukemias were treated in extremely high risk (ER). The SR patients with unequivocal CNS involvement (CNS3) at diagnosis were treated as an HR group. The patients in M1 marrow at day 33 with M2/M3 at the day 15 bone marrow (BM) were assigned to shift higher risk after induction therapy. Treatment of ALL-02 consists of early phase and maintenance phase. Early phase includes induction, consolidation, sanctuary (2 courses of high-dose MTX at a dose of 3g /m2), and re-induction therapy for 15 to 26 weeks depending on risk group. Prophylactic CRT was replaced by protracted TIT (MTX, CA, HDC) in all except the patients with CNS3 at diagnosis in ALL-02 trial. The patients with CNS3 at diagnosis received CRT at a dose of 12 Gy. Depending on the risk group, protracted TIT was given during induction, intensification and maintenance in ALL-02 (12 doses in SR and 15 in HR/ER). Accumulative doses of DEX were 120 mg/m2 in SR, whereas 170 mg/m2 in HR and 670 mg/m2 in ER. Treatment duration is 24 months for any risk. The patients assigned ER were candidate for allogeneic stem cell transplantation (SCT) by the end of early phase, provided HLA-matched siblings were available. The probability of event-free survival (EFS) and overall survival were constructed using the Kaplan-Meier method. Events in the analysis of EFS included induction failure, death, relapse and secondary malignant neoplasm. All statistical analyses were done according to intent-to treat methods. RESULTS: The numbers of patients at each risk in ALL-02 were 457 (40%) for SR, 543 (48%) for HR, and 139 (12%) for ER. The number of patients with CNS3 at diagnosis was 31 (2.7%). Of 1139 patients, 16 patients (1.4%) had CNS relapses of the leukemia (an isolated CNS relapse: 10 pts, a combined CNS and BM relapse: 6 pts). The 5-year EFS rate ALL-02 was 83.7% (SE=1.1), slightly better than for ALL-97 (79.3%, SE=1.7, p =0.054). The 5-year cumulative risk of an isolated and total CNS relapse was lower in ALL-02 than in ALL-97 (isolated CNS relapse: 0.9% vs 2.7%, p=0.017, total CNS relapse: 4.5% vs 1.4%, p =0.01). The proportion of CRT and SCT were 2%, 8% in ALL-02 respectively, whereas 31%, 11% in ALL-97 respectively. CONCLUSIONS: The ALL-02 trial found that CRT was abolished successfully, in all except those with CNS3 at diagnosis, with substitution of more intensive systemic chemotherapy and protracted TIT. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 255 Introduction: Standard treatment of acute myeloid leukemia (AML) comprises one or two cycles of chemotherapy to induce complete remission (CR) followed by postremission treatment in order to prevent relapse of the disease (consolidation therapy). In 2003, we initiated a prospective multicenter randomized trial to investigate the impact of different consolidation strategies on long-term outcome in AML patients ≤ 60 years. Consolidation options comprised upfront allogeneic stem cell transplantation (allo SCT) in aplasia after induction therapy, autologous SCT, and three cycles of standard high-dose-cytarabine-based consolidation. For patients receiving high-dose cytarabine, the main study aim was to evaluate the benefit of adding additional mitoxantrone and amsacrine to cytarabine consolidation. Design: From 2003 to 2009, 1182 patients (median age, 48 years; range 16–60 years) with untreated AML were randomly assigned at diagnosis to different consolidation strategies after classical 7+3 induction. According to the risk-adapted treatment strategy of the trial, cytogenetically or molecular intermediate-risk (IR) and adverse-risk (AR) patients should receive an allo SCT as consolidation treatment if an HLA-identical-sibling donor (IR) or HLA-matched related or unrelated donor (AR) was available. IR and AR patients with no available donor should receive autologous SCT. All favorable risk patients and patients with no available donor were scheduled for high-dose cytarabine based consolidation. Half of the patients were randomized for high dose cytarabine based consolidation. Half of the patients were randomized for high dose cytarabine alone while the other half received high dose cytarabine with the addition of amsacrine and mitoxantrone. Standard chemotherapy consisted of three cycles with high dose cytarabine (2 × 3 g/m2, day 1,3,5) whereas combined consolidation contained two cycles of MAC (cytarabine 2 × 1g/m2, day 1–6, mitoxantrone 10 mg/m2, day 4–6) plus one cycle of MAMAC (cytarabine 2 × 1 g/m2, day 1–5, amsacrine 100 mg/m2, day 1–5). In order to evaluate the effect of the two cytarabine based consolidation strategies, we determined overall survival (OS) and event free survival (EFS) using the method of Kaplan Meyer. Survival distributions were compared using the log rank test. Results: 1182 patients were randomized for further intervention (Arm A+B: n=582, 49.3%; Arm C+D: n=600, 50.7 %). Median follow-up was 41.4 months (95%-CI 39.3–43.6). A total number of 375 patients received allogeneic (n=322) or autologous SCT (n=53) and 807 patients were consolidated with cytarabine. Of these patients, 407 were randomized for cytarabine alone and 400were randomized to receive cytarabine plus mitoxantrone and amsacrine (MAC/MAC/MAMAC). Complete remission rate (CR) after second induction therapy was 59.1% (n=698). Between the four arms, there were no significant differences of the CR rates. Five-year OS of patients receiving high dose cytarabine alone was 47.1% (95%-CI 42.0–52.2%), for patients receiving MAC/MAMAC as consolidation therapy it was 46.8% (95%-CI 42.3–51.3%; p = 0.610). Three-year event free survival (EFS) was also not significant with 30.5% (95%-CI 26.6–34.4%) for patients receiving high dose cytarabine alone and 35.6% (95%-CI 31.7–39.5%; p = 0.059) for patients receiving MAC/MAMAC. Conclusions: According to our data, the addition of mitoxantrone and amsacrine to high dose cytarabine consolidation confers no benefit for treatment outcome in younger AML patients. Disclosures: No relevant conflicts of interest to declare.

Description: Abstract 1122 The survival of replicating B cells, with DNA damage arising from oxidative stress and/or activation-induced cytosine deaminase (AID), appears in part to be under p53 control. Importantly, a common C〉G single nucleotide polymorphism (SNP) within codon 72 of p53 influences p53 function. Among other differences, p53-72R (CGC=Arginine) is notably more effective than p53-72P (CCC=Proline) at inducing apoptosis. The SNP has been linked to clinical outcome in multiple settings, including malignancy. Most individuals in the US population display heterozygosity. In this study, we have examined whether B cells, whose genomic DNA is heterozygous for the codon 72 SNP, exhibit allelic exclusion at the level of expressed RNA. This was suggested by reported evidence that p53 expression is strongly regulated by gene methylation status; mRNA of peripheral blood cells from p53-72P/R heterozygous individuals is skewed toward the representation of only one SNP, depending upon ethnic status; and a p53 intron 2 SNP, representing a potential methylation site, is in strong linkage disequilibrium with the codon 72 SNP (PLoS ONE 6:e15320, 2011). Evidence for allelic exclusion of this functionally relevant p53 SNP would suggest that not all identically-stimulated B cells have equal likelihoods of survival within p53-72P/R heterozygous individuals. To investigate this issue, we first confirmed that p53 was expressed in non-transformed human B cells replicating in response to surrogate C3d-bound antigen, IL4 and BAFF. These physiologically-relevant stimuli synergize to induce a burst of T cell-independent clonal expansion, followed by apoptosis of many of the divided progeny (J. Immunol. 175:6143, 2005). Expression of p53 was monitored by immunoblotting and flow cytometry. Consistent with a role in regulating clonal burst size, p53 protein and mRNA/protein of p53-regulated pro-apoptotic genes were significantly elevated in blasts, prior to apoptosis. This contrasted with undectable p53 protein in non-stimulated B cells. To assess whether expressed p53 within a single lymphoblast derives from one allele, i.e. demonstrates allelic exclusion, we first identified tonsil donors heterozygous for the codon 72 polymorphism. This involved PCR-restriction fragment length polymorphism (RFLP) analysis of genomic DNA, as described by others (Leukemia Research 30:1113, 2006). Subsequently, purified resting B2 cells from cryopreserved tonsil cell suspensions, determined to be heterozygous for p53-72P/R, were labeled with CFSE and stimulated as above. At d5, single B lymphoblasts were sorted into 96 well PCR plates containing lysis buffer and cDNA prepared using random hexamer primers. A p53 sequence comprising exons 2a, 3, and 4 was subjected to two rounds of PCR amplification with the following primers, Forward: 5-cagccagactgccttccg-3 & Reverse: 5-gcaagtcacagacttggctg-3. Nucleotide sequencing of PCR-amplified p53 was performed commercially (Applied Biosystems Big Dye Terminator v3.1 cycle sequencing) and analyzed by chromasPro software. In two experiments, only 39 cells of a total of 236 assayed were positive for p53. By contrast, β-actin cDNA from two rounds of PCR amplification yielded 88% of the single cell-containing wells positive for actin. These yields indicate that p53 mRNA levels within a single cell are significantly more limiting than those for actin and are consistent with quantitative PCR of cDNA obtained from activated cell pools. Interestingly, analysis of the cDNA p53 chromatogram sequence of the p53-positive single cells (n=39), whose genomic DNA was heterozygous for the p53 codon 72 SNP, showed only a single homogenous sequence: either P (n=21) or R (n=18), but never both. This was in marked contrast to the chromatogram of cDNA derived from a pool of activated B cells within each experiment. In the latter cases, two overlapping peaks indicating co-expression of p72-P and p72-R were noted. Taken together, our findings suggest that p53 mRNA expression from a single non-transformed human B lymphocyte arises from the transcriptional activation of a single allele, i.e. shows allelic exclusion. Although the mechanism for this phenomenon requires further investigation, these results imply that B cells within individuals heterozygous for the functionally important p53-p72 polymorphism might vary considerably in their resistance to apoptosis. Disclosures: No relevant conflicts of interest to declare.

Description: HSCs are rare cells that have the unique ability to self-renew and differentiate into cells of all hematopoietic lineages. The lack of donors and current inability to rapidly and efficiently expand HSCs are roadblocks in the development of successful cell therapies. Thus, the challenge of ex vivo human HSC expansion remains a fertile and critically important area of investigation. Here, we show that either SALL4A- or SALL4B-transduced human HSCs obtained from the mobilized peripheral blood are capable of rapid and efficient expansion ex vivo by 〉10 000-fold for both CD34+/CD38− and CD34+/CD38+ cells in the presence of appropriate cytokines. We found that these cells retained hematopoietic precursor cell immunophenotypes and morphology as well as normal in vitro or vivo potential for differentiation. The SALL4-mediated expansion was associated with enhanced stem cell engraftment and long-term repopulation capacity in vivo. Also, we demonstrated that constitutive expression of SALL4 inhibited granulocytic differentiation and permitted expansion of undifferentiated cells in 32D myeloid progenitors. Furthermore, a TAT-SALL4B fusion rapidly expanded CD34+ cells, and it is thus feasible to translate this study into the clinical setting. Our findings provide a new avenue for investigating mechanisms of stem cell self-renewal and achieving clinically significant expansion of human HSCs.

Description: Abstract 2873 International staging system (ISS) and cytogenetics are the main prognostic factors of Multiple Myeloma (MM) but they reflect biologic characteristics of disease without taking into account individual host features. On the contrary, clinical characteristics of single patient could be substantial as to various points of view. For instance, in elderly MM patients, novel therapies reduction or interruption due to toxicity represent the major cause of unsatisfactory outcome. Therefore, it was empirically suggested different schedule of drugs in these “frail” patients but, how the “frailty” should be assessed in every single patient, is still unsettled. Advanced age, poor performance status (PS) and comorbidities are usually applied to recognize the “frailty” but it is not well known which of them are really prominent and whether these parameters, adjusted for conventional prognostic factors, still affect final outcome. We analyzed a population of symptomatic MM diagnosed from 2007 to 2010 included in the Marche Region MM Registry, to assess the frequency of “frailty” features, such as age, PS, comorbidities, cytopenias, renal insufficiency (RI) and lytic bone lesions, and their role on the overall survival (OS) when adjusted for prognostic factors. Comorbidities were scored according to Charlson Comorbidity Index (CCI) that split patients in 4 categories according to number and type of comorbidity. Patients were treated with transplant or standard therapy according to their eligibility. Overall, 88% of patients were treated with new drug-based therapies and 12% with MP. Median age of the 266 patients analyzed was 73 years (range 38–90). Twenty-four percent of patients had IgA MM, fifty patients (23%) had ISS stage=3 and 29/166 (17.5%) had unfavourable cytogenetics. Regarding “frailty” measures, 38% of patients had 〉 75 years, 39% had PS=2–4, 34% had 1 or more comorbidities. The most frequent comorbidities were hypertension (35%), heart diseases (22%), diabetes (15%), neurological diseases (16%), COBP (8%), secondary malignancies (8%) and chronic renal failure (6%). CCI ≥1 was detected in 51%. Increasing comorbitities number and CCI were associated with increased age although 37% of patients aged less than 65 years had CCI ≥2. Moreover, 35% had at least 2 cytopenias, 76% had bone disease and 14% had RI. Fifty patients (19%) died during follow-up. OS at 3 years was 74%. Univariate analysis performed on the total population determined age 〉 65 years (p=0.065), PS=2–4 (p

Description: Xanthomas are a common manifestation of lipid metabolism disorders. They include hyperlipemic xanthoma, normolipemic xanthoma, and a related condition, necrobiotic xanthogranuloma (NXG). All 3 forms can be associated with monoclonal immunoglobulin (MIg). In an attempt to improve diagnosis, understanding, and treatment of this association, we retrospectively analyzed a personal series of 24 patients (2 hyperlipemic xanthoma, 11 normolipemic xanthoma, and 11 NXG) and 230 well-documented reports from the literature. With the exception of the nodules and plaques featured in NXG, the clinical presentation of xanthomatous lesions usually resembled that seen in common hyperlipidemic forms and could not be used to suspect MIg-associated xanthomas. Extracutaneous sites were not rare. The MIg was an IgG in 80% of cases. Myeloma was diagnosed in 35%. Hypocomplementemia with low C4 fraction was present in 80% of studied patients. Low C1 inhibitor serum levels were found in 53%. Cryoglobulinemia was detected in 27%. These abnormalities suggest immune complex formation because of interactions between the MIg and lipoproteins and argue in favor of a causal link between MIg and xanthomas. Monoclonal gammopathy therapy could thus be an option. Indeed, among the patients who received chemotherapy, hematologic remission was accompanied by improvement in xanthoma lesions in several cases.

Description: Tumor cells that survive initial courses of chemotherapy may do so by acquiring a multidrug-resistant phenotype. This particular mechanism of drug resistance may also confer resistance to physiological effectors of apoptosis that could potentially reduce the efficacy of immune therapies that use these pathways of cell death. We have previously demonstrated high efficacy for a cytokine-based tumor cell vaccine in a murine MPC11 myeloma model. In the present study, the effects of this vaccination were compared in MPC11 cells and their isogenic sublines selected for mdr1/P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). Immunization with MPC11 cells expressing granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-12 (IL-12) led to long-lasting protection of mice against subcutaneous (sc) challenge with both parental cells or their MDR variants. Similarly, immunization with GM-CSF/IL-12–transfected MDR sublines caused rejection of transplantation of both parental cells and the MDR sublines. Whereas MPC11 cells and their MDR variants were resistant to APO-1/CD95/Fas ligand, the immunization generated potent granzyme B/perforin-secreting cytotoxic T lymphocytes (CTLs) that were similarly effective against both parental and isogenic MDR cells. We conclude that MDR mediated bymdr1/Pgp did not interfere with lysis by pore-forming CTLs. Immunotherapy based on pore-forming CTLs may be an attractive approach to the treatment of drug-resistant myeloma.

Description: Abstract 223 A coding variant form of GFI1 (GFI136N) increases the risk to develop AML by 60% and is present in about 10–15 % of all Caucasian AML patients. To determine the underlying molecular mechanism and potentially develop new therapeutic approaches, we generated “knockin” mouse strains wherein the endogenous murine Gfi1 gene was replaced either by the human GFI1 variant (GFI136N, the form predisposing to AML) or by the more common form of GFI1 (GFI136S). In most hematopoietic compartments no difference was observable between GFI136N and GFI136S expressing mice; however, there was a 3–5 fold increase in the number of granulocytic monocytic progenitors (GMPs) and common myeloid progenitors (CMPs) in Gfi136N expressing (either homozygous or heterozygous) mice compared to wild-type or Gfi136S expressing mice(p≤0.01). Interestingly, both human and murine AML leukemic cells are thought to originate from GMPs and CMPs. To assess functional differences, we seeded GMPs from GFI136N or GFI136S knockin mice on methylcelluose or transplanted them into into syngenic animals. We found that GFI136N expressing GMPs proliferate faster and have an increased self-renewal capacity both in-vitro and in-vivo compared to GMPs carrying Gfi136S alleles. A gene expression array analysis showed that GFI136N GMPs have a stem cell-like gene signature with elevated levels of Hoxa9 expression and a deregulation of a number of oncogenes involved in the development of human AML such as Trib2, Tet2 or Idh2. It is of particular interest that Hoxa9, a known GFI1 target gene, was up-regulated 3–4 fold in GFI136N GMPs compared to in GFI136S GMPs (p≤0.01). It is known that high levels of Hoxa9 accelerate AML development in mice and are associated with a poor prognosis in AML patients. GFI1 is a transcriptional repressor and exerts its function by recruiting different histone modifying enzymes, in particular LSD1, which de-methylates histone 3 (H3) at lysine 4 (K4), or histone deacetylases (HDACs), which remove acetyl groups from H3K9 residues and G9a, which initiates dimethylation of H3K9. Both H3K4 methylation and H3K9 acetylation correlate with actived gene expression, whereas H3K9dimethyl correlates with repession. Chromatin-immuno-precipitation (ChIP) of Gfi1-bound chromatin from Lin−Sca1−c-Kit+ cells, which contains the GMP population, showed that GFI136N binds to a lesser degree to the Hoxa9 locus than GFI136S. This diminished binding of Gfi136N correlated with an increased H3K4 dimethylation and H3K9 acetylation as well as diminished H3K9 dimethylation across the Hoxa9 locus in GFI136N cells. It is likely that these epigenetic changes lead to the increased Hoxa9 expression observed in GFI136N GMPs. A more exhaustive ChIP-Seq analysis with antibodies recognizing H3K4dimethyl in Lin−Sca1−c-Kit+ cells from Gfi136N or Gfi136S mice showed significant epigenetic alterations throughout the Hoxa9 locus genome and at other GFI1 target genes. It is conceivable that these epigenetic alterations explain, at least in part, the changed gene expression signatures in GFI136N GMPs. To investigate the role of GFI136N in myeloid leukemogenesis, we induced the expression of a mutated form of KRAS (K12D) in both GFI136N and GFI136S mice. All mice developed a deadly myelo-proliferative disorder, but animals carrying the GFI136N allele succumbed to the disease within a significantly shorter latency period (17 against 31 days, p≤0.01) than GFI136S mice. We also transduced GFI136N and GFI136S GMPs with retroviral vectors directing the expression of either the AML1-Eto9a or the MLL-AF9 onco-fusion proteins typically found in human AML. We observed that GFI136N GMPs expressing MLL-AF9 or AML1-Eto9a generated 5–10 fold more colonies (p≤0.01) on methylcellulose and exhibited a higher replating efficiency than the respective GFI136S GMPs. Finally, AML blast cells from GFI136N heterozygous patients expressed higher levels of HOXA9 compared to AML blasts from GFI136S homozygous patients, suggesting that our mouse model reflects the disease predisposition in human patients. Our knockin mice are, to our knowledge, the first animal model for a human genetic variation that predisposes to leukemia. Based on the findings with this model, we propose that the human GFI136N variant predisposes to AML by inducing epigenetic changes affecting the expression of important regulators with oncogenic potential such as Hoxa9. Disclosures: No relevant conflicts of interest to declare.

Description: We prove that the SH2-containing tyrosine phosphatase 1 (SHP-1) plays a prominent role as resistance determinant of imatinib (IMA) treatment response in chronic myelogenous leukemia cell lines (sensitive/KCL22-S and resistant/KCL22-R). Indeed, SHP-1 expression is significantly lower in resistant than in sensitive cell line, in which coimmunoprecipitation analysis shows the interaction between SHP-1 and a second tyrosine phosphatase SHP-2, a positive regulator of RAS/MAPK pathway. In KCL22-R SHP-1 ectopic expression restores both SHP-1/SHP-2 interaction and IMA responsiveness; it also decreases SHP-2 activity after IMA treatment. Consistently, SHP-2 knocking-down in KCL22-R reduces either STAT3 activation or cell viability after IMA exposure. Therefore, our data suggest that SHP-1 plays an important role in BCR-ABL–independent IMA resistance modulating the activation signals that SHP-2 receives from both BCR/ABL and membrane receptor tyrosine kinases. The role of SHP-1 as a determinant of IMA sensitivity has been further confirmed in 60 consecutive untreated patients with chronic myelogenous leukemia, whose SHP-1 mRNA levels were significantly lower in case of IMA treatment failure (P 〈 .0001). In conclusion, we suggest that SHP-1 could be a new biologic indicator at baseline of IMA sensitivity in patients with chronic myelogenous leukemia.

Description: A Rhesus D (RhD) red blood cell phenotype with a weak expression of the D antigen occurs in 0.2% to 1% of whites and is called weak D, formerly Du. Red blood cells of weak D phenotype have a much reduced number of presumably complete D antigens that were repeatedly reported to carry the amino acid sequence of the regular RhD protein. The molecular cause of weak D was unknown. To evaluate the molecular cause of weak D, we devised a method to sequence all 10RHD exons. Among weak D samples, we found a total of 16 different molecular weak D types plus two alleles characteristic of partial D. The amino acid substitutions of weak D types were located in intracellular and transmembraneous protein segments and clustered in four regions of the protein (amino acid positions 2 to 13, around 149, 179 to 225, and 267 to 397). Based on sequencing, polymerase chain reaction-restriction fragment length polymorphism and polymerase chain reaction using sequence-specific priming, none of 161 weak D samples investigated showed a normal RHD exon sequence. We concluded, that in contrast to the current published dogma most, if not all, weak D phenotypes carry altered RhD proteins, suggesting a causal relationship. Our results showed means to specifically detect and to classify weak D. The genotyping of weak D may guide Rhesus negative transfusion policy for such molecular weak D types that were prone to develop anti-D.

Description: Abstract 3986 Background: Multiple Myeloma (MM) is an incurable plasma cell neoplasm. Although current lenalidomide (R) and bortezomib containing up-front regimens can now achieve overall response rates approaching 100%, patients eventually relapse with progressively refractory disease. Histone deacetylase inhibitors (HDACi), in Phase I clinical trials in patients with multiple myeloma, have shown promising activity when combined with other agents such as bortezomib. Vorinostat, (suberoylanilide hydroxamic acid; SAHA) is an oral HDACi, currently FDA approved in the United States for the treatment of cutaneous T-cell lymphoma. Here we report the findings of the combination of vorinostat (Zolinza®), lenalidomide and dexamethasone (ZRD) in multiple myeloma patients who were refractory to RD. Methods: Patients received oral vorinostat 300 mg or 400 mg once daily (days 1–7 and days 15–21), lenalidomide 10–25 mg (days 1–21) and dexamethasone 20–40 mg weekly (days 1, 8, 15, 22) in a 28-day cycle Subjects: Twenty-nine patients were treated and all were refractory to RD; 76% were refractory to at least one bortezomib containing regimen and 48% were refractory to the combination of VRD. Twenty-six patients (90%) had undergone prior high dose therapy with autologous stem cell transplant. The median number of prior therapies was 4 (range 2–13). Results: The overall response rate (ORR) was 24 % with 1 VGPR and 6 PR. The clinical benefit rate (ORR + MR) was 51% including 8 MR. Nine patients (31%) had stable disease. The median duration of response (DOR) was 4 months (range, 0–36). The median overall survival (OS) was 11 months (range, 4–36). Common toxicities including diarrhea and fatigue (all grades) were 41% and 34% respectively. The incidence of grade 3/4 neutropenia was 45 % and grade 3/4 thrombocytopenia was 34%. Conclusion: The combination of ZRD showed significant activity in patients with RD relapsed/refractory multiple myeloma. ZRD was well tolerated and is a viable option for patients who do not respond to lenalidomide-based therapy. Further, since all 3 agents are available in oral formulations, ZRD provides an additional option for those patients wishing to avoid intravenous therapy. Formal phase II studies of this combination are in preparation. Disclosures: Off Label Use: Vorinostat is an oral HDAC inhibitor and is being evaluated in the treatment of Multiple Myeloma. Bilotti:Celgene: Consultancy, Speakers Bureau; Millenium: Consultancy, Speakers Bureau. McNeill:Celgene: Consultancy, Speakers Bureau; Millenium: Consultancy, Speakers Bureau. Graef:Merck: Employment. Vesole:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium: Speakers Bureau. Siegel:Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Millenium: Consultancy, Honoraria, Research Funding, Speakers Bureau; Merck: Consultancy.

Description: Embryonic stem cells can differentiate in vitro into hematopoietic cells through two intermediate stages; the first being FLK1+ E-cadherin− proximal lateral mesoderm and the second being CD45− VE-cadherin+endothelial cells. To further dissect the CD45−VE-cadherin+ cells, we have examined distribution of 4-integrin on this cell population, because 4-integrin is the molecule expressed on hematopoietic stem cells. During culture of FLK1+ E-cadherin− cells, CD45− VE-cadherin+4-integrin− cells differentiate first, followed by 4-integrin+ cells appearing in both CD45− VE-cadherin+ and CD45−VE-cadherin− cell populations. In the CD45−VE-cadherin+ cell population, 4-integrin+ subset but not 4-integrin− subset had the potential to differentiate to hematopoietic lineage cells, whereas endothelial cell progenitors were present in both subsets. The CD45−VE-cadherin− 4-integrin+ cells also showed hematopoietic potential. Reverse transcription-polymerase chain reaction analyses showed that differential expression of the Gata2 and Myb genes correlated with the potential of the 4-integrin+ cells to give rise to hematopoietic cell differentiation. Hematopoietic CD45−VE-cadherin+ 4-integrin+ cells were also present in the yolk sac and embryonic body proper of 9.5 day postcoitum mouse embryos. Our results suggest that the expression of 4-integrin is a marker of the earliest precursor of hematopoietic cell lineage that was diverged from endothelial progenitors.

Description: The granulocyte colony-stimulating factor receptor (G-CSF-R) activates multiple STAT proteins. Although the membrane-proximal cytoplasmic region of the G-CSF-R is necessary and sufficient for activation of STAT1 and STAT5, activation of STAT3 requires the membrane distal region that contains four tyrosines. Although one of these (Y704) has previously been shown to be involved in STAT3 activation from a truncated G-CSF-R derived from a patient with severe chronic neutropenia (SCN), this tyrosine is not required for STAT3 activation by the full-length G-CSF-R. To investigate possible alternative mechanisms of STAT3 activation, we generated a series of Ba/F3 cell transfectants expressing the wild-type G-CSF-R or mutant receptors that either completely lack tyrosines or retain just one of the four cytoplasmic tyrosines of the G-CSF-R. We show that, at saturating G-CSF concentrations, STAT3 activation from the full-length G-CSF-R is efficiently mediated by the C-terminal domain in a manner independent of receptor tyrosines. In contrast, at low G-CSF concentrations, Y704 and Y744 of the G-CSF-R play a major role in STAT3 activation. Both tyrosine-dependent and -independent mechanisms of STAT3 activation are sensitive to the Jak2 inhibitor AG-490, follow similar kinetics, and lead to transactivation of a STAT3 reporter construct, indicating functional equivalence. STAT3 activation is also impaired, particularly at nonsaturating G-CSF concentrations, in bone marrow cells from mice expressing a truncated G-CSF-R (gcsfr-▵715). These findings suggest that G-CSF–induced STAT3 activation during basal granulopoiesis (low G-CSF) and “emergency” granulopoiesis (high G-CSF) are differentially controlled. In addition, the data establish the importance of the G-CSF-R C-terminus in STAT3 activation in primary cells, which has implications for understanding why truncated G-CSF-R derived from SCN patients are defective in maturation signaling.

Description: We investigated whether interleukin-1β (IL-1β) is differentially expressed in plasma cells from monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) patients because IL-1β appears to play a major role in the development of lytic bone lesions, the major clinical feature distinguishing MGUS from myeloma. In situ hybridization (ISH) for IL-1β was performed using bone marrow aspirates from 51 MM, 7 smoldering MM, 21 MGUS, and 5 normal control samples. Using the ISH technique IL-1β mRNA was detectable in the plasma cells from 49 of 51 patients with active myeloma and 7 of 7 patients with smoldering myeloma. In contrast, 5 of 21 patients with MGUS and 0 of 5 normal controls had detectable IL-1β message. Bone lesions were present in 40 of the 51 MM patients analyzed, and all 40 patients had IL-1β mRNA by ISH. These results show that greater than 95% of MM patients but less than 25% of MGUS patients are positive for IL-1β production. In the future, continued follow-up of IL-1β positive and negative MGUS patients should determine whether aberrant expression of plasma cell IL-1β is predictive of those MGUS patients that will eventually progress to active myeloma.

Description: We performed nonmyeloablative HSCT in 6 patients with a newly described genetic immunodeficiency syndrome caused by mutations in GATA2—a disease characterized by nontuberculous mycobacterial infection, monocytopenia, B- and NK-cell deficiency, and the propensity to transform to myelodysplastic syndrome/acute myelogenous leukemia. Two patients received peripheral blood stem cells (PBSCs) from matched-related donors, 2 received PBSCs from matched-unrelated donors, and 2 received stem cells from umbilical cord blood (UCB) donors. Recipients of matched-related and -unrelated donors received fludarabine and 200 cGy of total body irradiation (TBI); UCB recipients received cyclophosphamide in addition to fludarabine and TBI as conditioning. All patients received tacrolimus and sirolimus posttransplantation. Five patients were alive at a median follow-up of 17.4 months (range, 10-25). All patients achieved high levels of donor engraftment in the hematopoietic compartments that were deficient pretransplantation. Adverse events consisted of delayed engraftment in the recipient of a single UCB, GVHD in 4 patients, and immune-mediated pancytopenia and nephrotic syndrome in the recipient of a double UCB transplantation. Nonmyeloablative HSCT in GATA2 deficiency results in reconstitution of the severely deficient monocyte, B-cell, and NK-cell populations and reversal of the clinical phenotype. Registered at www.clinicaltrials.gov as NCT00923364.

Description: In multiple myeloma (MM) pathogenesis, hyperdiploidy and nonhyperdiploidy are recognized as 2 major cytogenetic pathways. Here, we assessed the role of hyperdiploidy in 426 patients with monoclonal plasma cell disorders, among them 246 patients with AL amyloidosis (AL), by interphase fluorescence in situ hybridization. Hyperdiploidy was defined by a well-established score requiring trisomies for at least 2 of the 3 chromosomes 5, 9, and 15. The hyperdiploidy frequency in AL was a mere 11% compared with 30% in monoclonal gammopathy of undetermined significance (P 〈 .001) and 46% in AL with concomitant MM I (P 〈 .001). Overall, hyperdiploidy was associated with an intact immunoglobulin, κ light chain restriction, higher age, and bone marrow plasmacytosis, but was unrelated to the organ involvement pattern in AL. Clustering of 6 major cytogenetic aberrations in AL by an oncogenetic tree model showed that hyperdiploidy and t(11;14) were almost mutually exclusive, whereas gain of 1q21 favored hyperdiploidy. Deletion 13q14 and secondary IgH translocations were equally distributed between ploidy groups. We conclude that the interphase fluorescence in situ hybridization–based hyperdiploidy score is also a feasible tool to delineate hyperdiploid patients in early-stage monoclonal gammopathies and that the cytogenetic pathogenetic concepts developed in MM are transferable to AL.

Description: Abstract 98 Background: Advanced follicular lymphomas (FL) are incurable with conventional chemotherapy and there is no consensus on the best treatment approach. The SWOG cancer research cooperative group and Cancer and Leukemia Group B (CALGB) compared the safety and efficacy of two immunochemotherapy regimens for FL in a Phase III randomized intergroup protocol (S0016) that enrolled 554 patients with previously untreated, advanced stage FL between 3/1/2001 and 9/15/2008. Methods: Pts were eligible if they had advanced stage (bulky stage II, III or IV) evaluable FL of any grade (1, 2, or 3) and had not received any prior therapy. In one arm (CHOP-R), patients received 6 cycles of CHOP chemotherapy (750 mg/m2 cyclophosphamide, 50 mg/m2 doxorubicin, 1.4 mg/m2 vincristine, and 100 mg prednisone daily for 5 days) at 3 week intervals with 6 doses of rituximab anti-CD20 antibody (375 mg/m2 on days 1, 6, 48, 90, 134 and 141 according to the schedule described by Czuczman et al.[J.Clin.Oncol 17:268, 1999]). In the second arm of the protocol, patients received 6 cycles of CHOP, followed by a dosimetric infusion of tositumomab/iodine I-131 tositumomab and then 1–2 weeks later a therapeutic infusion of I-131-tositumomab labeled with sufficient I-131 (median 85 mCi) to deliver a total body dose of 75 cGy (CHOP-RIT). The study was designed to have 86% power to detect a hazard ratio (HR) of CHOP-RIT to CHOP-R of 0.67 for 2 yr PFS based on a one-sided.021 level test (accounting for 3 interim analyses). Results: Of the 554 enrolled pts, 532 were eligible and 526 were evaluable for toxicity (263 on each arm of the protocol). Pt characteristics (age, sex, race, stage, beta 2 microglobulin level, tumor bulk, B symptoms) were well-balanced in the two arms of the protocol. In general, both regimens were well-tolerated (Table I). Median follow-up time among patients still alive is 4.9 years. One hundred and six of 267 eligible pts on the CHOP-R arm have progressed or died compared to 86 of 265 eligible pts on the CHOP-RIT arm. The 2 year estimate of PFS was 76% on the CHOP-R arm and 80% on the CHOP-RIT arm (Figure 1). In multivariate Cox regression adjusting for the stratification factor (serum beta-2 microglobulin level), the hazard ratio for CHOP-RIT vs. CHOP-R was 0.79 (95% CI: 0.60–1.05, p=.11 [2-sided] or p=.06 [1-sided]). Twenty-six of 267 pts on the CHOP-R arm have died compared to 40 of 265 eligible pts on the CHOP-RIT arm. The 2-year estimate of overall survival was 97% on the CHOP-R arm and 93% on the CHOP-RIT arm. In multivariate Cox regression adjusting for the stratification factor serum beta-2 microglobulin, the hazard ratio for CHOP-RIT vs. CHOP-R was 1.55 (95% CI: 0.95–2.54, p=.08 [2-sided]). Conclusion: No statistically significant differences in PFS, OS, or serious toxicities are yet demonstrable with either regimen administered in this trial. However, PFS and OS are outstanding with either of the two regimens with median times to progression not yet reached for either treatment. Future studies will be needed to assess whether combining CHOP-R with RIT consolidation and with maintenance rituximab will confer additive benefit, as being evaluated in a follow-up trial (SWOG protocol S0801) that has recently completed accrual. Disclosures: Press: Spectrum: Consultancy, Honoraria; Roche/Genentech: Consultancy, Honoraria, Research Funding. Off Label Use: Front-line use of I-131-tositumomab for consolidation therapy in 1st remission of follicular lymphoma. Friedberg:Genentech: Consultancy, Honoraria. Czuczman:Glaxo Smith Kline: Consultancy, Research Funding; Genentech: Consultancy, Honoraria. Kaminski:Glaxo Smith Kline: Patents & Royalties. Maloney:Genentech/Roche: Consultancy, Honoraria, Speakers Bureau; Glaxo Smith Kline: Consultancy, Honoraria, Speakers Bureau. Cheson:Glaxo Smith Kline: Research Funding. Fisher:Roche: Consultancy, Honoraria.

Description: Abstract 1131 Humanin (HN), a 24-amino acid endogenous antiapoptotic peptide, was initially shown to protect against neuronal cell death by Alzheimer's disease-related insults. It has recently been found that an exogenous analog of HN (HNG) in which the 14th amino acid serine is replaced with glycine protected against cerebral and cardiac ischemia reperfusion (I/R) injury in cortical neurons and cardiomyocytes, respectively. Platelet activation and thrombus formation has been shown to play an important role during I/R injury by exacerbating the extent of the infarct size. However, it is presently unknown whether HNG affects platelet function and the subsequent arterial thrombus formation. We thus examined whether HNG affects platelet activation and thrombus formation both in vitro and in vivo. Human platelets were isolated from healthy adults. Preincubation of washed human platelets with HNG (4μM) reduced collagen- or convulxin-induced platelet aggregation by 56.8% (P

Description: Targeted mutation of the myeloid transcription factor C/EBPɛ in mice results in gram-negative septic death at 3 to 5 months of age. This study defines the underlying molecular defects in their terminal granulocytic differentiation. The mRNA for the precursor protein of the cathelin-related antimicrobial peptides was almost completely absent in the bone marrow cells of C/EBPɛ−/− mice. This finding may help explain their susceptibility to gram-negative sepsis, because both are bacteriocidal peptides with potent activity against gram-negative bacteria. Superoxide production was found to be reduced in both granulocytes and monocytes of C/EBPɛ−/− mice. While gp91 phox protein levels were normal, p47phox protein levels were considerably reduced in C/EBPɛ −/− granulocytes/monocytes, possibly limiting the assembly of the NADPH oxidase. In addition, expression of mRNA of the secondary and tertiary granule proteins, lactoferrin and gelatinase, were not detected, and levels of neutrophil collagenase mRNA were reduced in bone marrow cells of the knock-out mice. The murine lactoferrin promoter has a putative C/EBP site close to the transcription start site. C/EBPɛ bound to this site in electromobility shift assay studies and mutation of this site abrogated binding to it. A mutation in the C/EBP site reduced the activity of the promoter by 35%. Furthermore, overexpression of C/EBPɛ in U937 cells increased the activity of the wild-type lactoferrin promoter by 3-fold. In summary, our data implicate C/EBPɛ as a critical factor of host antimicrobial defense and suggests that it has a direct role as a positive regulator of expression of lactoferrin in vivo.

Description: Cellular methotrexate (MTX) resistance may cause treatment failure in childhood common/preB-acute lymphoblastic leukemia (c/preB-ALL), T-lineage ALL (T-ALL), and acute myeloid leukemia (AML). The ex vivo potency of several antifolates (MTX, trimetrexate [TMQ], GW1843U89, multitargeted antifolate [MTA], Raltitrexed, and ZD9331) was studied via in situ inhibition of thymidylate synthase (TS). After short-term exposure, relapsed c/preB-ALL (rALL, n = 21), T-ALL (n = 22), and AML (n = 22) were 3-fold, 10-fold, and 6-fold less sensitive to MTX (P ≤ .01) compared with initial c/preB-ALL (n = 43). This difference in resistance was not observed for TMQ. Also for GW1843U89 and MTA, no resistance was observed in rALL and AML compared with c/preB-ALL. T-ALL compared with c/preB-ALL tended to be less resistant to GW1843U89 (3-fold) and MTA (6-fold) than to MTX (10-fold) (P= .06). Raltitrexed was more active against c/preB-ALL compared with the other subtypes. After 21 hours continuous incubation, T-ALL and AML samples were equally sensitive as c/preB-ALL to MTX, but rALL was 3-fold resistant to MTX compared with initial c/preB-ALL (P = .003). The resistance of rALL was circumvented by TMQ (1-fold; P = .03) and GW1843U89 (1.4-fold; P= .004). Novel antifolates, except MTA, displayed a more potent TS inhibition than MTX during continuous exposure. These results suggest that MTX resistance in AML and T-ALL can be circumvented by continuous exposure, and that novel antifolates should be explored further for MTX-resistant T-ALL, rALL, and AML cells.

Description: The gene PIGA encodes one of the protein subunits of the 1-6-N acetylglucosaminyltransferase complex, which catalyses an early step in the biosynthesis of glycosyl phosphatidylinositol (GPI) anchors. PIGA is somatically mutated in blood cells from patients with paroxysmal nocturnal hemoglobinuria (PNH), leading to deficiency of GPI-linked proteins on the cell surface. To investigate in detail how inactivating mutations of the PIGA gene affect hematopoiesis, we generated a mouse line, in whichloxP-mediated excision of part of exon 2 occurs on the expression of Cre. After crossbreeding with EIIa-cre transgenic mice, recombination occurs early in embryonic life. Mice that are mosaics for the recombined Piga gene are viable and lack GPI-linked proteins on a proportion of circulating blood cells. This resembles the coexistence of normal cells and PNH cells in patients with an established PNH clone. PIGA(−) blood cells in mosaic mice have biologic features characteristic of those classically seen in patients with PNH, including an increased sensitivity toward complement mediated lysis and a decreased life span in circulation. However, during the 12-month follow-up, the PIGA(−) cell population did not increase, clearly showing that a Piga gene mutation is not sufficient to cause the human disease, PNH.

Description: Shwachman-Diamond syndrome (SD), an inherited disorder with varying cytopenias and a marked tendency for malignant myeloid transformation, is an important model for understanding genetic determinants in hematopoiesis. To define the basis for the faulty hematopoietic function, 13 patients with SD (2 of whom had myelodysplasia with a clonal cytogenetic abnormality) and 11 healthy marrow donors were studied. Patients with SD had significantly lower numbers of CD34+ cells on bone marrow aspirates. SD CD34+ cells plated directly in standard clonogenic assays showed markedly impaired colony production potential, underscoring an intrinsically aberrant progenitor population. To assess marrow stromal function, long-term marrow stromal cell cultures (LTCs) were established. Normal marrow CD34+ cells were plated over either SD stroma (N/SD) or normal stroma (N/N); SD CD34+cells were plated over either SD stroma (SD/SD) or normal stroma (SD/N). Nonadherent cells harvested weekly from N/SD LTCs were strikingly reduced compared with N/N LTCs; numbers of granulocyte-monocyte colony-forming units (CFU-GM) derived from N/SD nonadherent cells were also lower. SD/N showed improved production of nonadherent cells and CFU-GM colonies compared with SD/SD, but much less than N/N. Stem-cell and stromal properties from the 2 patients with SD and myelodysplasia did not differ discernibly from SD patients without myelodysplasia. We conclude that in addition to a stem-cell defect, patients with SD have also a serious, generalized marrow dysfunction with an abnormal bone marrow stroma in terms of its ability to support and maintain hematopoiesis. This dual defect exists in SD with and without myelodysplasia.

Description: T-cell reconstitution after bone marrow transplant (BMT) is characterized, for at least 1 year, by the expansion of populations of T cells with a primed/memory phenotype and by reverse CD4/CD8 proportions. T lymphocytes from 26 BMT patients (mostly adults) were obtained at various times after transplantation (from 45 to ≥730 days) and were tested for susceptibility to spontaneous apoptosis and anti-Fas triggered apoptosis in vitro. Substantial proportions of CD4+ and CD8+ cells generated during the first year after transplantation, but not by day 730, exhibited in these assays decreased mitochondrial membrane potential (▵Ψm) and apoptotic DNA fragmentation. The apoptotic phenotype tended to disappear late in the follow-up period, when substantial absolute numbers of naive (CD45RA+/CD62-L+) T cells had repopulated the peripheral blood compartment of the BMT patients. The rate of spontaneous cell death in vitro was significantly correlated with lower levels of ex vivo Bcl-2 protein, as assessed by cytofluorometry and Western blot analysis. In contrast, the levels of Bax protein remained unchanged, resulting in dysregulated Bcl-2/Bax ratios. Cell death primarily concerned the expanded CD8+/CD45R0+ subpopulation, although CD45R0− subpopulations were also involved, albeit to a lesser extent. These results show that the T-cell regeneration/expansion occurring after BMT is accompanied by decreased levels of Bcl-2 and susceptibility to apoptosis.

Description: The neoplastic cells of classical Hodgkin’s disease (cHD), ie, Hodgkin and Reed-Sternberg cells (HRS cells), contain clonally rearranged Ig genes, but are dissimilar to normal B cells in that they mostly do not display B-cell antigens such as CD20 or CD19. The transcription factor B-cell–specific activator protein (BSAP) influences numerous B-cell functions such as B-cell antigen expression, Ig expression, and class switch. We analyzed the expression of BSAP in cHD and control tissues by isotopic in situ hybridization and immunohistochemistry to determine whether BSAP is expressed in HRS cells and, if so, whether it may be involved in the genesis of the abnormal phenotype of these cells. Both in normal lymphoid tissue and non-Hodgkin lymphomas, BSAP transcripts and protein were almost exclusively found in B cells and B-cell lymphomas (40 cases), but were absent from the tumor cells of T-cell neoplasms (41 cases), including 19 cases of anaplastic large cell lymphoma of T- and null-cell type. Among cHD, variable numbers of HRS cells exhibited BSAP transcripts (22 of 25 cases) and protein (28 of 31 cases). Our findings show that BSAP is sufficiently specific to serve as B-cell marker. BSAP expression in HRS cells provides further strong evidence for a frequent B-cell origin of cHD and helps distinguish this disease from anaplastic large cell lymphoma of T- and null-cell type. Because BSAP is much more frequently expressed in HRS cells than the conventional B-cell antigens, the abnormal immunophenotype of HRS cells with frequent absence of B-cell antigens does not appear to be due to absent BSAP expression.

Description: CD4+ T helper 1 (Th1) cells and Th2 cells are distinguished based on the pattern of cytokines they are able to produce. Selectin ligands and chemokine receptors are differentially expressed in Th1 and Th2 cells, providing a basis for tissue-specific recruitment of helper T-cell subsets. However, the modes and mechanisms regulating tissue-specific localization of Th1 and Th2 cells are still largely unknown. Here, we show the preferential expression on Th1 cells of the integrin 6/β1, which is distinctly regulated by the Th1-inducing cytokines interleukin-12 (IL-12) and interferon-alfa (IFN-). The pattern of integrin 6/β1 regulation closely mirrors that of the chemokine receptor CCR1. Analysis of signal transducer and activator of transcription 4 (Stat4) activation by IL-12 and IFN- shows distinct signaling kinetics by these cytokines, correlating with the pattern of CCR1 and integrin 6/β1 expression. Unlike IFN-, the ability of IL-12 to generate prolonged intracellular signals appears to be critical for inducing integrin 6/β1 upregulation in Th1 cells. The expression and upregulation of CCR1 and 6/β1 integrin promotes the migration of Th1 cells. These findings suggest that the exquisite regulation of integrin 6/β1 and CCR1 may play an important role in tissue-specific localization of Th1 cells.

Description: Human immunodeficiency virus (HIV) entry is mediated not only by the CD4 receptor, but also by interaction with closely related molecules that act as membrane coreceptors. We have analyzed mRNA expression and/or cell membrane exposition of the coreceptors most widely used by diverse HIV-1 strains (CXCR4, CCR5, and CCR3) on purified hematopoietic progenitor cells (HPCs) induced in liquid suspension culture to unilineage differentiation/maturation through the erythroid (E), granulocytic (G), megakaryocytic (Mk), and monocytic (Mo) lineages. Reverse transcriptase-polymerase chain reaction (RT-PCR) and cytofluorimetric analysis showed the presence of both CXCR4 and CCR5 in quiescent HPCs, but failed to detect CCR3-specific transcripts. Chemokine expression in HPC progenies showed that CXCR4 receptor is detected on the majority of MKs from early to late stages of maturation, whereas it is moderately decreased in the Mo lineage. In the G pathway, two distinct cell populations, CXCR4+ and CXCR4−, were observed: morphological analysis of the sorted populations showed that the CXCR4+ cells were largely eosinophils and the CXCR4− were granulocytes of the neutrophilic series. Furthermore, in the E pathway, CXCR4 was almost completely absent. CCR5 expression is restricted to Mo cultures, ie, ≈30% to 80% cells throughout all monocytopoietic differentiation/maturation stages. Finally, CCR3 mRNA is always absent in all the unilineage cultures. Evaluation of CD4 expression by flow cytometry on both quiescent HPCs and differentiating unilineage precursors showed that the CD4 receptor is present on ≈15% of the starting CD34+ HPC population, highly expressed in the Mo lineage up to 80% at terminal maturation, present on 20% to 30% of maturing Mks, and not detectable in either the E or G lineage. Expression of CD4 receptor together with CXCR4 and/or CCR5 coreceptor in the four lineages correlates with hematopoietic precursor susceptibility to T-lymphotropic and macrophage (M)-tropic HIV strains infection: (1) CD4− G and E cells were resistant to both M-tropic and T-lymphotropic strains; (2) HPC-derived Mks were susceptible to T-tropic, but resistant to M-tropic, infection; (3) Mo differentiating cells efficiently replicate both HIV strains. Furthermore, we showed that the CXCR4 and CCR5 ligands (stromal-derived factor 1 and macrophage-inflammatory protein-1 [MIP-1], MIP-1β and RANTES, respectively) inhibit HIV replication in both maturing Mo and Mk cells. Taken together, our data show a lineage-specific modulation of chemokine receptor/coreceptor during hematopoietic cell differentiation and extend previous observations on the relationship between the expression of HIV receptor/coreceptors, susceptibility, and chemokine-mediated resistance to HIV infection.