Background :Different clinical outcomes of umbilical cord blood (CB) transplantation and GM-CSF mobilized peripheral blood stem cell (LB) transplantation stimulated our interests in immune characteristics of various stem cell sources so that we investigated immunophenotypes of mononuclear cells of twenty-six CB and ten LB cases and twenty normal adult peripheral blood (AB). Method :Two-color direct immunofluorescence analysis was performed using FACScan (Becton-Dickinson, USA) and monoclonal antibodies were CD34FITC/CD33PE, CD34FITC/CD45ROPE, CD34PE/CD45RAFITC, CD34PE/CD38FITC, CD4PE/CD45RAFITC, CD4FITC/CD45ROPE, CD8PE/CD45RAFITC, CD8PE/CD11bFITC, CD8PE/CD57FITC, CD8FITC/CD38PE (Serotec), and Simulset IMK lymphocyte kit (Becton-Dickinson). Result :CD34+ cell frequencies of CB and LB were four times higher than that of AB. CD34+CD38- cell frequency was higher in CB, 41.5±28.1% compared to 20.1±15.8% in LB (P=0.0391). LB showed higher frequency of CD3+ and CD8+ cells and lower frequency of CD4+ and CD19+ cells compared to those of CB and AB. CD4+CD45RA+ naive cell frequency was higher in CB (29.3%) compared to 2.3% of LB. CD4+CD45RO+ memory T cell frequency (8.5%) and CD8+CD57+ cell frequency (1.0%) were lowest in CB. CD8+CD45RA+ and CD8+CD11+ cell frequencies showed no difference. CD8+CD11+ cell frequency was higher in Vaginal delivery (11 ±7.6%) compared to that (4.0±2.3%) in Cesarean section (P =0.0081). Conclusion :CB showed higher frequency of immature hematopoietic stem cell precursors and na ve lymphocytes compared to that of LB and AB. LB showed higher frequency of T lymphocytes and lower frequency of B lymphocytes compared to those of CB and AB, which might be the possible causes of the different clinical outcome. Study on the standard immunophenotypic values in various hematopoietic stem cell products using sufficient numbers of subjects is necessary for the guideline of clinical utilization.

Keywords: Umbilical cord blood, GM-CSF mobilized peripheral blood stem cell, Immunophenotyping