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Immune clinical events and pattern of recovery of total lymphocytes, T cells and CD4+/CD8+ T cell subsets, B cells and NK cells, were analysed after allogeneic blood cell transplantation (BCT) for 12 months following transplant (n = 33). Results were compared with immune recovery after allogeneic bone marrow transplantation (BMT) (n = 15) and autologous blood cell transplantation (n = 19). Rates of acute GVHD were comparable in the two allotransplantation groups. Fourteen out of 17 evaluable alloBCT group patients have presented an extensive cGVHD. Total T cell, CD4+T cells and CD56+NK cell reconstitution were improved in alloBCT group vs alloBMT group. CD4+/CD8+ ratio evolution were improved in alloBCT group vs alloBMT and autoBCT groups. These results confirm that rapid immune recovery is associated with allogeneic blood stem cell transplantation.

Massive ascites of donor T-cell origin in a patient with acute GVHD after a reduced-intensity allograft for CLL

The destruction of cells capable of initiating and maintaining leukemia challenges the treatment of human acute myeloid leukemia. Recently, CD34+/CD38- leukemia progenitors have been defined as new leukemia-initiating cells less mature than colony-forming cells. Here we show that CD34+/CD38- leukemia precursors have reduced in vitro sensitivity to daunorubicin, a major drug used in leukemia treatment, in comparison with the CD34+/CD38+ counterpart, and increased expression of multidrug resistance genes (mrp/lrp). These precursors show lower expression of Fas/Fas-L and Fas-induced apoptosis than CD34+/CD38+ blasts. Moreover, the CD34+/CD38- leukemic subpopulation induces a weaker mixed leukocyte reaction of responding T-lymphocytes than the CD34+/CD38+ leukemic counterpart, either in a MHC-unmatched or MHC-matched settings. This weaker immunogenicity could be linked to lower expression on CD34+/CD38- leukemia precursors of major immune response molecules (MHC-DR, LFA-3, B7-1, or B7-2) than CD34+/CD38+ leukemic cells. Nonetheless, the susceptibility of the immature CD38- precursors to cytotoxicity was not different from the sensitivity of the CD38+ counterpart. Finally, CD34+/CD38- leukemia precursors, in contrast with CD38+ precursors, failed, under appropriate conditions, to differentiate into dendritic cells, a central step for antigen recognition. This is to our knowledge the first demonstration that the very immature phenotype of CD34+/CD38- leukemic progenitors confers both chemotherapy resistance and decreased capacities to induce an immune response. Because the susceptibility of the immature leukemia cells as cytotoxic targets is maintained, our data underline the importance of improving the initial steps of leukemia recognition, more particularly by defining optimal conditions of dendritic cell transformation of the very immature hematopoietic precursors.

The purpose of the present study was the detection of tumor cells in aphereses after mobilization of peripheral blood stem cells (PBSCs) with G-CSF from 39 breast cancer patients. Circulating tumor cells were searched using sensitive immunocytochemical technique (APAAP) with three anticytokeratin monoclonal antibodies. Counting of mononuclear cells and CD34 progenitor cells was also performed. Circulating tumor cells were detected in 35% of the patients. Cytokeratin-positive cells were detected in 45% of the patients of the metastatic group compared with 20% of the non metastatic one. Aphereses contamination was not correlated with lymph node involvement. Numbers of mononuclear cells and CD34 cells were not significantly different in positive and negative PBSCs collections. In our study, presence of tumor cells was associated with advanced clinical stage and could not be related to a higher CD34 cells mobilization by G-CSF.

Over a 10 year period, we transplanted 63 patients with acute lymphoblastic leukaemia (ALL) who had achieved first complete remission (CR). All were15 years old and 45 (71%) had at least one poor prognostic factor. Twenty-nine patients with a suitable sibling underwent autologous bone marrow transplantation (BMT). Beginning in 1984, patients without a donor received an allogeneic BMT (34 patients). Preparation consisted of cyclophosphamide (CY)/TBI (78%) or melphalan (Mel)/TBI (22%); marrow was treated in vitro in 31 patients (allogeneic: 7; autologous: 24). Kaplan-Meier estimates of the probability at 6 years of relapse, survival and DFS were 41% (allogeneic: 10%, autologous: 65%, p0.05), 44% (allogeneic: 62%, autologous: 26%, p = NS) and 42% (allogeneic: 62%, autologous: 27%, p0.06), respectively. This report confirms that allogeneic BMT permits long-term remissions giving high levels of survival when performed shortly after entering first CR while autologous BMT, when performed in the same setting, is less successful at preventing relapse. This study also confirms the high sensitivity of ALL to the graft-versus-leukemia effect provided by allogeneic BMT. Chemoradiotherapy dose intensification delivered at autologous BMT is not sufficient to prevent relapses. Autologous BMT must therefore be augmented by other approaches of which immunotherapy may be one.