Primitive hematopoietic progenitor cells are present in peripheral blood autografts.
In this report we have used an in vitro assay for long-term culture-initiating cells (LTC-IC) to detect primitive hematopoietic progenitor cells (HPC) in the peripheral blood (PB) of cancer patients who received high-dose cyclophosphamide (HD-CTX) followed by a combination of recombinant hematopoietic growth factors (C-HGF) including either interleukin-3 (IL-3) + granulocyte colony-stimulating factor (G-CSF), IL-3 + granulocyte-macrophage colony-stimulating factor (GM-CSF) or IL-3/GM-CSF fusion protein (PIXY-321). In addition, we have developed a quantitative assay for cells capable of generating additional colony-forming cells (pre-CFC) as a means of determining primitive HPC present in mobilized PB cells. CD34+ human leukocyte A (HLA)-DR- cells isolated from the mobilized PB were capable of initiating long-term hematopoiesis in vitro that persisted for 10 weeks, while CD34+ HLA-DR- cells obtained from the nonmobilized PB or BM were capable of sustaining long-term hematopoiesis in vitro for only 4 weeks and 8 weeks, respectively. As determined by a limiting dilution analysis of mobilized PB CD34+ HLA-DR- cells, the frequency of pre-CFC was 4.3% (range, 1.0-8.3%). Pre-CFC comprised 0.01% (range, 0.001-0.02%) of mobilized PB mononuclear cells, and 151 pre-CFC were calculated to be present in one milliliter of mobilized PB (range, 20-310/ml). These results suggest that PB mononuclear cells collected by leukapheresis following mobilization with HD-CTX + C-HGFs contain not only differentiated HPCs but also more primitive HPC.
Tong
J
J
Hematology/Oncology Section, Indiana University School of Medicine, Indianapolis, USA.
Gianni
A M
AM
Siena
S
S
Srour
E F
EF
Bregni
M
M
Hoffman
R
R
D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34; D001772:Blood Cell Count; D001773:Blood Cells; D001853:Bone Marrow / Q000473:pathology; D001943:Breast Neoplasms / Q000097:blood* / Q000188:drug therapy; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D003520:Cyclophosphamide / Q000494:pharmacology; D006684:HLA-DR Antigens / Q000032:analysis; D006410:Hematopoiesis / Q000187:drug effects; D016298:Hematopoietic Cell Growth Factors / Q000494:pharmacology; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells; D006801:Humans; D007937:Leukapheresis; D008228:Lymphoma, Non-Hodgkin / Q000097:blood / Q000188:drug therapy; D011994:Recombinant Proteins / Q000494:pharmacology; D014182:Transplantation, Autologous
D015703:Antigens, CD; D018952:Antigens, CD34; D006684:HLA-DR Antigens; D016298:Hematopoietic Cell Growth Factors; D011994:Recombinant Proteins; D003520:Cyclophosphamide