Hematology and cell therapy最新文献

Gamma-irradiation-induced DNA single- and double-strand break (SSB and DSB) formation and their repair kinetics in normal hematopoietic cells and in leukemic lymphocytes was investigated using alkaline and neutral comet assays. The cells were isolated by density gradient centrifugation from peripheral blood of patients with chronic lymphocytic leukemia (CLL) and from healthy study subjects. Furthermore, CD34+ progenitor cells isolated with immunomagnetic beads from bone marrow of non-leukemic persons were investigated. The cytotoxicity of 137Cs irradiation was determined in vitro in peripheral blood mononuclear lymphocytes from 36 CLL patients and from 8 healthy donors using radioactive leucine incorporation assay in 4-day culture. A dose-dependent increase in DNA migration was observed in alkaline (SSBs) and neutral (DSBs) gel electrophoresis when the cells were exposed to gamma-irradiation doses up to 10.4 Gy. After irradiation with doses of 2.4 and 5.4 Gy, the cells repaired their single- and double-strand breaks almost completely. The formation and repair of DNA strand breaks were essentially similar in all normal cell populations investigated and in CLL cells. The gamma-irradiation-induced cytotoxicity did not correlate with DNA strand break formation and repair capacity. According to these results, the differences of gamma-irradiation tolerance among individual CLL cases and among healthy persons are explicable in terms other than DNA strand break formation or repair.

In recent years, we have initiated two clinical studies, to evaluate the usefulness of ex-vivo expanded cells in patients with breast cancer who receive sequential high-dose chemotherapy. Ex-vivo expanded cells were produced from autologous cryopreserved bone marrow nucleated cells, using a biomedical device. The Aastrom Replicell system cultures cells in animal serum-replete medium, with a combination of flt3-L, PIXY321 and Epo, for 12 days. The initial pilot trial was set up to establish the feasibility and safety of the technique: 6 patients completed the study. An ongoing randomized study searches to establish whether ex-vivo expanded cells provide a clinical benefit.

Unlabelled: We report hereby the results of the french multicentric randomized PEGASE 04 protocol established to evaluate the impact on survival of high-dose chemotherapy over conventional chemotherapy for MBC patients.

Patients and methods: Inclusion criteria were: age < or = 60 year, PS < 2, adenocarcinoma initially metastatic or in first relapse, chemosensitive disease. Randomization was done after 4-6 courses of conventionnal chemotherapy between high-dose (Mitoxantrone, 45 mg/m2, Cyclophosphamide: 120 mg/kg, Melphalan: 140 mg/m2), and the pursuit of the same conventionnal chemotherapy. Between 09/92 and 12/96, 61 chemosensitive patients were enrolled: 29 were referred to standard chemotherapy, 32 to intensive therapy. At randomization, 13 pts (21.3%) were in complete response and 48 in partial response.

Results: The median progression-free survivals were 20 and 35.3 months in the standard and intensive groups (p=0.06). The relapse rates were respectively 79.3% vs 50.8% at 3 years and 90.8% vs 90.7% at 5 years. The median overall survivals were 20 and 43.4 months, with an overall survival rate of 18.5% vs 29.8% at 5 years (p=0.12).

Conclusion: The CMA regimen could prolong the progression-free survival of MBC patients, however without any significant impact on overall survival.

T-cell depletion (TCD) of the bone marrow graft remains the most effective method to prevent severe graft versus host disease after allogeneic bone marrow transplantation. Early studies of HLA-identical sibling transplants showed that although T-cell depletion decreased GVHD, T-cell depleted transplants had higher risks of graft failure and leukemia relapse, leukemia free survival (LFS) was not improved compared to non-T-cell depleted transplants. In order to avoid graft failure and increased risk of relapse associated with this approach, we initiated a pilot study of T-cell depletion of the marrow graft combined with reinfusion of a fixed quantity of CD2+ peripheral blood T-cells. Depletion technique consisted in negative purging using CD2 and CD7 monoclonal antibodies (MoAbs) followed by rabbit complement cytolysis. This approach was associated with an intensified conditioning regimen using total body irradiation, high-dose cytosine arabinoside and melphalan (TAM) for all but one patient. Twenty-one patients were included with a mean age of 40 years. Only one acute severe Graft Versus Host Disease (GVHD) was observed and all patients engrafted. At 63 months, probability of survival is 42.86% with a relapse risk of 19.89%, two patients died from B-cell lymphoproliferative disease, seven other died from the procedure partially because of the use of the TAM as pretransplant regimen. This approach is being pursued by a gene therapy trial using herpes-simplex - 1 thymidine kinase gene expressing peripheral donor T-cells.

This study allowed evaluation and comparison of the precision (20 samples) and agreement (200 samples) of the relative and absolute values of the monocyte count using three methods: microscopic, flow cytometry and the automated ABX Vega hematology analyzer. Flow cytometry is the most precise method, even if the coefficient of variation of the automated analyzer is very similar. The coefficient of correlation between the ABX Vega and the flow cytometer is very satisfactory (r=0.8042). This study of the agreement also made it possible to confirm the difficulty that automated hematology analyzers have in differentiating between some granulocytes and monocytes and their propensity to overstimate the latter when the sample includes immature forms of granulocytes. This fact stresses the importance of the microscopic method, despite its lack of precision. The observed discrepancies did not lead to any difficulties in clinical interpretation; however, this finding should be taken into consideration, particularly in myleoproliferative syndromes and the laboratory monitoring of chemotherapy.

Through two clinical studies, tumor cells were searched for in the bone biopsies and cytapherisis of patients suffering from inflammatory tumors and who had undergone intensive therapy and autografts (Pegase 2 program). In these studies we used immunocytochemical test with two monoclonal antibodies. The results have shown the presence of tumor cells in 14% of the patients (respectively 18%), with no correlation to the appearance of metastases after 4 years in the first study. Nevertheless, the presence of these tumor cells seems to be an important factor in the number of relapses. It seems important to develop research into tumor contamination especially in the selection of grafts over the next few years.

High dose chemotherapy (HDC) for breast cancer has been used for some 15 years. All studies demonstrate a high response rate with approximately 20% prolonged (> 3 years) disease free survival among patients who achieved complete remission (CR) following HDC. Debate about the value of HDC has centered around the issue of patient selection, including selection by chemotherapy response. Results of one randomised, published trial of HDC versus conventional dose treatment, however, demonstrate a better outcome for the HDC group with a higher CR rate and prolongation of survival. These results have been updated and continue to show a stable proportion of long term complete remitters. In the adjuvant setting one recent trial has demonstrated no benefit from HDC 'consolidation' in 'high-risk' patients. Results of a number of other studies are pending and will help to settle this issue. The article reviews issues including patient selection by prior chemotherapy response, other methods of selection, the chemotherapy regimens used and the timing of HDC. While additional and confirmatory studies are required HDC for breast cancer remains an effective treatment modality.