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Post-graft hematopoiesis is characterized by long-term quantitative deficiency in marrow progenitor cells in both autologous and allogenic settings. In order to evaluate the function of post-graft progenitor cells, the proliferative capacity of marrow CD34(+) cells was evaluated in 10 patients 6 months after autologous bone marrow transplantation (ABMT) for non-Hodgkin's lymphoma and compared to that of 10 patients before ABMT and 10 normal controls. Immuno-selected CD34(+) cells were cultured for 7 days in liquid serum-free medium with a combination of early-acting GF consisting of stem cell factor, IL-3 and IL-1beta. Clonogenic efficiency of unselected cells for CFU-GM and BFU-E was decreased in post-graft patients compared to pre-graft and control patients. However, clonogenic efficiency of selected CD34(+) cells for CFU-GM was not different in post-graft, pre-graft and control patients but BFU-E values of post-graft patients remained lower than those of control patients. Decreased percentages of CD34(+) CD38(-) cells were observed in both post-graft and pre-graft patients while those of CD34(+) c-kit(+) cells were similar in all three patient groups. After 7-day liquid culture, expansion yields of total progenitor cells were significantly lower in post-graft patients (147 +/- 28%) than in pre-graft (255 +/- 27%) and control patients (246 +/- 23%). Post-graft deficiency in progenitor cell expansion was particularly marked for BFU-E (61 +/- 24%) compared to pre-graft patients (220 +/- 82%) and to controls (349 +/- 82%). These results indicate impaired proliferative potential of marrow CD34(+) cells several months after ABMT involving erythroid progenitor cells and/or commitment towards erythroid lineage from a more immature stage (pre-CFU).

Hematopoietic reconstitution has been studied in 180 patients after autologous bone marrow transplantation based on peripheral blood cell (PBC) recovery time and marrow progenitor counts sequentially tested for up to 4 years. Several factors that could influence hematopoietic reconstitution have been analyzed including sex, age, diagnosis, disease status, conditioning regimen, graft progenitor content, graft in vitro purging, and postgrafting administration of growth factors. Before transplantation, marrow progenitor values were normal only for colony-forming unit granulocyte macrophage (CFU-GM) in contrast to colony-forming unit-erythroid (CFU-E), burst-forming unit-erythroid (BFU-E), and colony-forming unit-megakaryocyte (CFU-Meg). After transplantation, as described with allogenic grafts, these values remained low for several years, although PBC counts were nearly normalized within a few weeks. Pregraft values were reached after 2 years for CFU-GM and BFU-E, and after 4 years for CFU-E, while CFU-Meg failed to reach pregraft values after this time. Normal levels were reached after 4 years only by CFU-GM. On univariate and multivariate analysis, the following factors appeared to delay both PBC and marrow progenitor reconstitution: underlying disease (particularly acute myeloid leukemias), graft characteristics such as low stem cell content and in vitro purging, conditioning regimens with total body irradiation or busulfan, and lack of postgraft administration of growth factors. In conclusion, high-dose therapy followed by bone marrow transplantation induces a deep and prolonged impairment of hematopoiesis irrespective of any alloimmune reaction or postgraft immunosuppressive therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Objective The aim of this study was designed to compare the in vivo long-term hematopoietic potential of bone marrow and peripheral blood grafts. Materials and Methods Marrow progenitor cell recovery was assessed for up to 4 years in 227 patients. One hundred patients were treated for malignant lymphomas by autologous bone marrow transplantation (BMT) and 127 by peripheral blood progenitor cell transplantation (PBPCT). Results Marrow progenitor cell counts were decreased for several years with both bone marrow and peripheral blood grafts. They were not different according to the origin of the graft, despite the reduced duration of peripheral blood cell recovery observed after PBPCT. Granulocyte colony-stimulating factor (G-CSF) used for PB graft mobilization and after transplantation resulted in faster neutrophil recovery compared to granulocyte-macrophage colony-stimulating factor (GM-CSF) with no evidence of decreased marrow progenitor cell recoveries. On the other hand, postgraft administration of GM-CSF enhanced long-term colony-forming unit granulocyte-macrophage reconstitution only after BMT. Factors that influenced marrow progenitor cell reconstitution have been identified by univariate and multivariate analysis: age, gender, type of lymphoma, and postgraft administration of hematopoietic growth factors (HGF) for the whole patient group; gender, graft progenitor cell yields, and type of HGF (G-CSF vs GM-CSF) for the PBPCT group; and only type of HGF for the BMT group. Conclusion Despite faster peripheral blood cell recovery, persistent deficiency of marrow progenitor cells was found several years after PBPCT, as observed after BMT. G-CSF–mobilized PBPCT resulted in faster neutrophil recovery compared to GM-CSF mobilization, with no difference in long-term hematopoietic reconstitution.