title: Comparative study of CD34-positive cells and subpopulations in human umbilical cord blood and bone marrow.
abstract: The CD34-positive population of bone marrow cells contain not only committed myeloid, erythroid, megakaryocytic and lymphoid progenitor cells but also more primitive stem cells capable of initiating haemopoiesis in long-term marrow culture that are termed long-term culture initiating cells (LTC-IC). Recently, different subpopulations of BM CD34+ cells have been defined. Thus the CD34+/CD45RO+ fraction contains both BFU-E and LTC-IC whereas CFU-GM are mainly CD34+/CD45RA+ and CD34+/CD33+. As human umbilical cord blood (UBC) also contains CD34+ cells and has been used as a source of material for clinical transplantation, we have undertaken a comparative study of the expression of CD34RO, CD45RA, CD33 and CD38 on CD34+ cells from UCB and BM using directly conjugated antibodies and flow cytometry. The frequency of CD34 cells in UCB (mean 1.0% +/- 0.3%) was similar to that in harvested pelvic BM (0.8% +/- 0.4%). The frequencies of CD34+ cells co-expressing CD33 (UBC: 54.1% +/- 28.7%; BM: 52.9% +/- 18.5%) and CD45RA (UBC: 24.8% +/- 16.6%; BM: 21.1% +/- 19.7%) were not significantly different between UCB and BM. In contrast, a significantly higher percentage of UCB-CD34+ cells co-expressed CD45RO+ (19.7% +/- 10.3%) compared with BM-CD34+ cells (7.2% +/- 5.3%; p < 0.001). The absolute number of CD34+ cells in UCB correlated with the number of committed myeloid (CFU-GM) and erythroid (BFUe) progenitors; a similar relationship was found for the absolute number of CD34+/CD33+ cells. However, the numbers of CD34+/CD45RO+ cells showed no correlation with numbers of committed progenitors.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Haematology, City Hospital, Nottingham, UK.
authors.forename: D
authors.initials: D
authors.lastname: Kinniburgh
authors.forename: N H
authors.initials: NH
authors.lastname: Russell
mesh_terms: D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD / Q000032:analysis*; D018952:Antigens, CD34; D000943:Antigens, Differentiation / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001853:Bone Marrow / Q000276:immunology*; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D005312:Fetal Blood / Q000166:cytology* / Q000276:immunology*; D005434:Flow Cytometry; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000276:immunology; D006801:Humans; D007536:Isomerism; D017493:Leukocyte Common Antigens / Q000032:analysis; D008562:Membrane Glycoproteins; D063268:Sialic Acid Binding Ig-like Lectin 3; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D000943:Antigens, Differentiation; D015214:Antigens, Differentiation, Myelomonocytic; C571163:CD33 protein, human; D008562:Membrane Glycoproteins; D063268:Sialic Acid Binding Ig-like Lectin 3; D017493:Leukocyte Common Antigens; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1