ALBERT

Description: To study transplanted unperturbed and mobilized long-term hematopoiesis after selection with an alkylating agent, bone marrow (BM) from 5 C57BL/6J mice was pooled, repeatedly transduced with retroviruses encoding the alkylating agent resistance protein O6-Methylguanine-DNA and enhanced green fluorescent protein (eGFP) as an easily traceable marker. Between 1 to 9x105 transfected BM cells were transplanted into 15 myeloablatively irradiated sex-mismatched C57BL/6J mice. Subsequently, 3 to 4 selection rounds with BCNU/O6-BG were carried out, enriching eGFP marked hematopoiesis in these mice up to 70–90%. Between 1 and 7x107BM cells of different mice were transplanted according to marrow location into groups of 5 sex-matched Bri44[1] mice. Two mice each received BM from the hind limbs, two from the pelvis and one received cells from the spleen, only, respectively. Altogether the study comprised 15 groups divided into 6 female and 9 male groups. Of these, 4 male and 3 female groups received 3 HSC-mobilization courses with G-CSF at intervals of 2 months starting 3 month after transplantation. Hematopoiesis in the other fraction remained unperturbed. During the observation period of 11–14 months in these tertiary recipients, repeated FACS analyses as well as linear amplification mediated (LAM) PCRs were carried out to track the clonal contributions. A decrease in the percentage of eGFP expressing marked hematopoiesis was observed in most cases. However, eGFP expression never disappeared altogether and could still be detected in the different hematopoietic lineages and successfully sorted for further analyses by MoFlo (Dako-Cytomation). Assessment of the clonal status of the Bri44 by LAM-PCR displayed interesting results. In some mice a decline in clone numbers was observed, whereas clone numbers remained stable in others. Tertiary transplantation with long-term follow-up indicates that this observation may be related to the transplantation of limited long-term repopulating clone numbers and progenitor cell exhaustion over time.

Description: Continuous infusion (CI) of coagulation factor concentrates has been used since the early 1990s. Recent reports of the occurrence of an inhibitor (inh) after CI have raised concerns about this method of treatment. We conduct a retrospective study to investigate the development of inh after CI of FVIII concentrates in Germany. 99 haemophilia treating physicians in Germany were contacted and asked to answer a questionnaire. So far data of 13 departments have been reported and analyzed. Three of these 13 centers never conducted a CI, in 5 no inh were detected and in 5 haemophilia centers 10 patients with inh development after CI were registered. 5 of these patients were suffering from severe, 1 from moderate and 4 from mild haemophilia (age between 7 months and 57 years). Indications for treatment were major bleeds and surgical procedures. Plasma derived (6) and recombinant (4) factor concentrates were given in various infusion sets. Data concerning infused amount (4300 to 〉100000 IE), exposure days (1 to 〉100) and inh characteristic (alloantibodies, 3 LR, 7 HR) were collected. Regarding the genotype, we found 4 missense-mutations, 2 intron-22-inversions, 1 small deletion, 3 were unknown. In our own center we found no inh in 81 patients with major orthopaedic surgery and bolus infusion of factor VIII concentrate compared to 2 inh in 8 patients with major orthopaedic surgery and CI of FVIII. In conclusion we found only in 2 patients the typical gene mutation for inh development. Strikingly the inh developed very often in patients with mild haemophilia. These findings agree with published results. There might be an uncommon inh-pathomechanism due to CI or patients with mild haemophilia might exhibit a much higher prevalence of inhibitor development when treated with an “intensive FVIII-treatment” such as CI.

Description: The prognostic value of histologic classification and single histomorphologic parameters in Hodgkin disease has been widely debated in the literature. Whereas several former studies identified single parameters to be of clinical relevance, some recent reports have doubted the prognostic value of histology using modern treatment. Grading of the largest histologic category of Hodgkin disease, nodular sclerosis (NS), has been controversially discussed concerning clinical relevance. In this study, 965 cases of NS were reviewed to assess 9 histomorphologic parameters. The histologic results were correlated with laboratory and clinical findings and with overall survival and disease-free survival. Based on these results, a new grading of the NS category was established. The new grading, based on the 3 criteria eosinophilia, lymphocyte depletion, and atypia of the Hodgkin/Reed-Sternberg cells, was a significant indicator of prognosis in intermediate and advanced stages. Patients investigated in this study represent an outstanding collection because all of them were enrolled in the prospective multicenter clinical trial of the German Hodgkin Lymphoma Study Group. All of them had been staged uniformly according to the Ann Arbor system and had received stage-adapted modern treatment according to multimodality protocols. A subtle analysis of histology could represent a possible way to identify patients with a significantly better or worse prognosis. This new grading should help to avoid overtreatment to reduce severe therapy-related side effects such as acute toxicity and chronic sequelae such as cardiopulmonary complications and secondary neoplasias.

Description: It has recently been shown that the transcription factor Erg, an Ets family member, drives constitutive expression of the intercellular adhesion molecule 2 (ICAM-2) in human umbilical vein endothelial cells (HUVECs) and that its expression is down-regulated by the pleiotropic cytokine tumor necrosis factor α (TNF-α). To identify other Erg target genes and to define its function in the endothelium, a combined approach of antisense oligonucleotides (GeneBloc) and differential gene expression was used. Treatment of HUVECs with Erg-specific GeneBloc for 24, 48, and 72 hours suppressed Erg mRNA and protein levels at all time points. Total RNA extracted from HUVECs treated withErg-specific or control GeneBloc was analyzed for differences in gene expression using high-density, sequence-verified cDNA arrays containing 482 relevant genes. Inhibition ofErg expression resulted in decreased expression ofICAM-2, as predicted. Four more genes decreased in Erg-deficient HUVECs were the extracellular matrix proteinsSPARC and thrombospondin, the adhesive glycoprotein von Willebrand factor, and the small GTPaseRhoA. Each of these molecules has been directly or indirectly linked to angiogenesis because of its role in vascular remodeling, adhesion, or shape change. Therefore, the role of Erg in vascular remodeling was tested in an in vitro model, and the results showed that HUVECs treated with Erg GeneBloc had a decreased ability to form tubulelike structures when grown on Matrigel. These results suggest that Erg may be a mediator of the TNF-α effects on angiogenesis in vivo.

Description: Rituximab proved to be effective in relapsed and refractory indolent NHL as a single agent and generated impressive results in phase II studies in combination with chemotherapy. In a prospective randomized trial we compared the efficacy and toxicity of rituximab (375 mg/m² d 1) plus MCP-chemotherapy ( mitoxantrone 8 mg/m² d 3 + 4, chlorambucile 3 x 3 mg/m² d 3 – 7, prednisolone 25 mg/m² d 3 – 7 ) given every 28 days for a total of 8 cycles versus MCP (d 1 – 5) x 8 cycles alone in advanced indolent NHL and MCL. Efficacy endpoints included overall and complete response rates, event free survival, progression free survival, overall survival and toxicity. For response assessment classical definitions have been used. Between 10/98 and 09/03 we randomized 358 patients (pts) with advanced stage follicular lymphoma (FL) (grade 1 + 2), lymphoplasmacytic lymphoma and MCL to either R-MCP or MCP. The study arms are well balanced for all demographic factors. 201/358 pts (56%) had FL. Both regimens were well tolerated with a low incidence of serious adverse events. The overall response rate (RR) and the complete response rate (CR) for all pts was 85,5% and 42% in the R-MCP arm versus 65,5% and 20% in the MCP arm (p

Description: HIV-based lentiviral vectors (LV) have become powerful tools for in vivo gene transfer and gene expression in non-dividing cells after local injection. However, the potential of in vivo bone marrow stem cell gene transfer by “in situ” bone cavity injection has not been well unexplored. This in vivo approach could take full advantage of any source of stem cells present in bone cavity and avoid many of the difficulties encountered by ex vivo hematopoietic stem cell (HSC) gene transfer. To determine if intra bone marrow (iBM) injection of LV can efficiently transduce BM stem cells, a 3rd-generation self-inactivating LV, containing eGFP regulated transcriptionally by a CMV promoter, was used to inject intra-femorally into adult Boy/J Ly45.1 mice (at 2 x106 IU/mouse). Blood counts were normal in all LV-injected mice (n=4) and buffer-injected mice (n=4). GFP-expressing peripheral blood leukocytes (PBL) were observed in both myeloid (up to 4%) and lymphoid subpopulations (up to 2%) 3-month post injection. To evaluate gene transfer and transgene expression in multi-potential progenitors, the colony-forming cell (CFC) assay was performed using low-density bone marrow 4-months post injection, resulting in 4–5% GFP+ CFU-granulocyte macrophage (CFU-GM) and CFU-granulocyte, erythroid, macrophage and megakaryocyte (CFU-GEMM). This was consistent with the 4-color FACS analysis data demonstrating that up to 3.7% of HSC/progenitors (Lin−c-kit+Sca1+ cells) from LV-injected mice expressed GFP transgene 4-months post injection. To further evaluate HSC gene transfer, BM from injected mice was transplanted into lethally irradiated adult C57/Bl6 (Ly45.2) mice. Four months later, successful engraftment was demonstrated in all BM recipients with 97–99% donor-derived cells in PBL and 91–93.3% in BM. Moreover, significant levels of GFP+ CFU were observed in all recipients ranging from 8.4 ± 2.3% to 17.7 ± 4.2%. To further study the LV-mediated gene transfer profile in HSC, mesenchymal progenitors and systemic distribution by intra-femoral injection, molecular analyses are in progress including real-time QPCR and clonality analysis by LAM-PCR. Our results indicate successful LV-mediated gene transfer into HSC by iBM injection. These data would potentially open a door to a novel approach for treatment of human diseases, but also provide a new tool to study adult stem cell plasticity and the nature of hematopoiesis.

Description: Erythroid progenitors undergo renewal (proliferation without apparent differentiation) in response to erythropoietin (Epo), stem cell factor (SCF), and glucocorticoids (dexamethasone) (Dex). SCF and Dex cooperate with Epo to promote proliferation and inhibit differentiation of erythroid progenitors, while Epo alone is required to protect erythroid cells from apoptosis during terminal red cell maturation. To examine the mechanism of the synergistic interactions of Epo, SCF, and Dex, we analyzed gene expression patterns using DNA chip–based large-scale comparative gene profiling using microarrays enriched in hematopoietic transcripts or containing randomly selected genes. Differentially regulated genes were validated by real-time reverse transcription–polymerase chain reaction (RT-PCR). The results reveal cooperative regulation of gene expression by glucocorticoids and Epo/SCF on a number of genes, such as CIS, BTG1, VDUP1, CXCR4, GILZ, and RIKEN29300106B05. While Epo and SCF never showed opposite effects on gene expression, Dex either enhanced or attenuated the effect of Epo and/or SCF. Several glucocorticoid receptor (GR)–target genes were regulated by Dex only in the presence of Epo and/or SCF, suggesting that the GR functions in the context of a larger transactivation complex to regulate these genes. The data also suggest that modulation of cytokine-induced signals by the GR is an important mechanism in erythroid progenitor renewal.

Description: Ex vivo proliferation of hematopoietic stem cells (HSCs) is important for cellular and gene therapy but is limited by the observation that HSCs do not engraft as they transit S/G2/M. Recently identified candidate inhibitors of human HSC cycling are transforming growth factor-β1(TGF-β1) and stroma-derived factor–1 (SDF-1). To determine the ability of these factors to alter the transplantability of human HSCs proliferating in vitro, lin− cord blood cells were first cultured for 96 hours in serum-free medium containing Flt3 ligand, Steel factor, interleukin-3, interleukin-6, and granulocyte colony-stimulating factor. These cells were then transferred to medium containing Steel factor and thrombopoietin with or without SDF-1 and/or TGF-β1 for 48 hours. Exposure to SDF-1 but not TGF-β1 significantly increased (〉 2-fold) the recovery of HSCs able to repopulate nonobese diabetic/severe combined immunodeficiency mice. These results suggest new strategies for improving the engraftment activity of HSCs stimulated to proliferate ex vivo.

Description: Damage of endothelial cells (EC) is known to be involved in pathogenesis of microangiopathy, hepatic veno-occlusive disease, sepsis, capillary leak syndrome, and acute or chronic graft-versus-host disease (GvHD) as major causes of morbidity and mortality in patients after hematopoietic stem-cell transplantation (HSCT). We recently demonstrated in 39 patients undergoing allogeneic stem cell transplantation that numbers of circulating EC (CEC) increased significantly after conditioning regimens and that patients treated with reduced intensity conditioning (RIC) showed significantly lower cell numbers (Woywodt et al., Blood, 2004 May 1;103(9):3603-5). Here we report on the measurement of plasma levels of von Willebrand factor (vWF), thrombomodulin (TM), PAI-I and TAFI in the course of HSCT. Measurement of vWF, TM, PAI-I and TAFI was performed in the 39 patients (20 male, 19 female; n = 21: HLA-matched unrelated donor; n = 18: related donors). Blood samples were collected before starting conditioning regimen (day −7), the day before transplantation (day −1) and at day +7, +14 and +21 after transplantation. 28 patients received a conventional regimen with cyclophosphamide (120 mg/kg) and either total body irradiation with 12 Gy (n = 14) or busulfan (16 mg/kg, n = 14). 11 patients undergoing stem-cell transplantation were treated with reduced intensity conditioning with fludarabine (150 mg/m²) and busulfan (8 mg/kg body) or melphalan (120 mg/m²). Median baseline vWF was elevated (262%, range 68–612, normal range: 50–150). Median baseline PAI-I (11.3 U/l; range 1.8–34.4; normal range: 〈 20) and median baseline TAFI (90%; range 46–126; normal range: 70–120) were within normal limits. TM level was lower than normal values (median 3.95 ng/ml; range 2.69–9.36; normal range: 6.6–10.6). Levels of vWF increased after conditioning regimen and remained elevated until day +21 (day −1: median 262; day+7: 268; day +14: 327; day +21: 374; p 〈 0.01). Median TM remained low at all time points (day −1: median 4.26; day +7: 3.86; day +14: 3.97; day +21: 4.52). Levels of TAFI remained unchanged (day −1: median 82; day +7: median 91, day +14: median 88; day +21: median 89). There were also no differences in levels of PAI-I before or after conditioning regimen or after transplantation (day −1: median 11.4, day +7: median 10.8, day + 14: median 14, day + 21: median 11.8). There was no significant difference in vWF in patients undergoing reduced intensity conditioning compared to patients treated with conventional regimens. Interestingly, there was no correlation between the endothelial markers as vWF and TM and numbers of CEC. Our data indicate that significant alterations of the hemostatic system occur in patients undergoing HSCT. Further studies are warranted to define the clinical role of both, hemostatic alterations and CEC in the course of HSCT.

Description: In allogeneic stem cell transplantation (SCT) T-cell depletion reduces transplant related mortality by diminishing GVHD. We have investigated a myeloablative regimen for matched unrelated donor SCT using both in vivo and in vitro CAMPATH-1H for effective T-cell depletion, utilising DLI at a later time point for graft versus tumor effect if necessary. Thirty patients (median age 33 years, range 18–48) were transplanted from January 1997 to June 2002. Diagnoses were: CML CP (n=9), CML AP (n=2), AML/MDS (n=9), ALL (n=8), NHL (n=1) and Fanconi anemia (n=1). Six patients had one HLA mismatch, the others were identical for HLA A, B, C, DR and DQ. Conditioning consisted of CAMPATH-1H 5mg/d on days −8 to −4, TBI 6 Gy on days −8 and −7 and cyclofosfamide 60 mg/kg on days −6 and −5. T-cell depletion was performed by in vitro incubation of the graft with 20 mg CAMPATH-1H for 30 minutes (Campath “in the bag”). Post-transplant GVHD prophylaxis consisted of cyclosporine A and methotrexate. The stem cell source was bone marrow in 19 patients (63%) and peripheral blood in 11 patients. One graft failure was observed, all other patients had sustained engraftment of donor cells. Acute GVHD was observed in 12 patients (40%), maximally grade I-II skin. No severe acute GVHD (grade III-IV) was experienced. Limited chronic GVHD developed in 2 patients, resolving after treatment. Only in one patient extensive chronic GVHD developed, which did not resolve. CMV reactivation occurred in 23% of patients, one patient developed CMV disease. No EBV disease was observed. Ten patients received donor lymphocyte infusion (DLI) at a median of 17.4 months after SCT (8 patients with relapsed CML, one patient with relapsed ALL, one patient with autoimmune hemolytic anemia). After DLI acute GVHD grade I-II developed in 4 patients, and GVHD grade III-IV in 3. Chronic GVHD developed in 5 patients, of which 2 extensive, resolving in all except one patient. With a median follow up of 37 (range 21–84) months 17 patients are alive (57%). One of the CML patients shows persistence of molecular disease not responding to increasing doses of DLI. All other patients are in CR with the CML patients in molecular remission. Five patients (17%) died because of relapsed disease (2 AML/MDS and 3 ALL). Treatment related mortality was 26% (1 rejection, 2 GVHD, 1 myocardial infarction, 4 infections). In conclusion, matched unrelated donor SCT following myeloablative conditioning using T-cell depletion with CAMPATH-1H in vivo as well as in vitro results in good engraftment, minimal grade I-II GVHD and an overall survival of 57%. Relapse rate was not increased with this strategy. This regimen appears to be successful for young adults with high-risk malignancies.