Experimental hematology
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Experimental hematology · Dec 1995
Comparative StudyDifferential effect of type I interferons on hematopoietic progenitor cells: failure of interferons to inhibit IL-3-stimulated normal and CML myeloid progenitors.
We observed a differential effect of type I interferons (IFNs) in inhibiting the proliferation of various hematopoietic progenitor cell types. Upon stimulation with interleukin-3 (IL-3), IFN-alpha and IFN-beta failed to inhibit colony formation of myeloid progenitors (day-14 colony-forming units-granulocyte/macrophage [CFU-GM]) obtained from peripheral blood (PB) and bone marrow (BM) of untreated chronic myelogenous leukemia (CML) patients in chronic phase even at IFN doses as high as 10,000 U/mL. In contrast, day-7 CFU-GM stimulated with granulocyte colony-stimulating factor (G-CSF) and burst-forming units-erythroid (BFU-E) were readily inhibited by moderate doses of IFNs. ⋯ The failure of IFN to inhibit immature myeloid progenitors was confirmed in normal and CML cells highly enriched in CD34-expressing cells. Combinations of growth factors were required for sufficient colony formation in these cells, whereas IL-3 alone provided only an inadequate stimulation, which was further inhibited by IFN. In purified CD34+ cells, day-14 CFU-GM were protected from IFN-mediated inhibition only upon stimulation with stem cell factor (SCF) in combination with IL-3 or G-CSF.
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Experimental hematology · Dec 1995
5-Fluorouracil-resistant CD34+ cell population from peripheral blood of CML patients contains BCR-ABL-negative progenitor cells.
Despite the marked expansion of leukemic cells observed in the hematopoietic system of chronic myeloid leukemia (CML) patients, there is clinical and experimental evidence that normal nonclonal cells persist in the bone marrow (BM) and peripheral blood (PB) of patients in the early chronic phase. In this study, we attempt to select the benign progenitor-enriched population from the PB of CML patients. The CD34+ cells isolated from the PB of 12 CML patients in the chronic phase were treated with low doses (5 or 10 micrograms/mL) of 5-fluorouracil (5-FU). ⋯ For the presence of BCR-ABL, mRNA from each of the 12 patients was studied by reverse-transcriptase-polymerase chain reaction (RT-PCR) on 10-15 pooled CFU-GM colonies plucked from methylcellulose cultures of starting and expanded populations. Although all PCR results were positive for colonies harvested before liquid culture, we were able to identify BCR-ABL-negative colonies from an expanded CD34+ population cultured in the presence of recombinant cytokines in 11 of 12 patients studied. 5-FU pretreatment of CML CD34+ cells markedly reduced their clonogenic potential and growth factor-mediated cell proliferation but favored higher frequency of BCR-ABL-free colonies. In conclusion, these data show that 5-FU-resistant CD34+ cells from the PB of CML patients contain normal progenitor cells, which can be selected and expanded in short-term cytokine-mediated cultures.
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Experimental hematology · Dec 1995
Hematopoietic growth factors after HLA-identical allogeneic bone marrow transplantation in patients treated with methotrexate-containing graft-vs.-host disease prophylaxis.
The use of hematopoietic growth factors (HGFs) in the allogeneic transplant setting has sometimes been avoided for fear of stimulating leukemic cell growth and intensifying graft-vs.-host disease (GVHD). However, neither an increase in relapse rate nor an aggravation of GVHD has been routinely described when HGFs are used after allogeneic bone marrow transplantation (allo-BMT). Early outcomes after HLA-matched allo-BMT in 26 patients with hematologic malignancies treated with recombinant human granulocyte colony-stimulating factor (rhG-CSF) or recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) from the day of transplantation were analyzed. ⋯ A decrease in the number of early deaths from fungal or bacterial infections was found in the cytokine-treated group (p = 0.05). These data suggest that the early use of rhG-CSF or rhGM-CSF after HLA-matched allo-BMT in hematologic malignancies accelerates engraftment, reduces hospitalization time, and improves outcome, without increasing acute GVHD or early relapse. Because MTX-based prophylaxis regimens are associated with prolonged neutropenia, the routine use of HGFs after transplantation may be particularly useful in regimens including MTX.