Abstract • 59

A major investigative effort of our laboratory has been directed toward the evaluation of hematopoietic stem cells from different sources for transplantation. We compared and characterized the functional and phenotypic characteristics of fetal bone marrow (FBM), adult bone marrow (ABM), cord blood (CB) and peripheral blood (PBMC). A striking difference in the phenotypic composition, such as CD34+ cells of FBM, ABM, PBMC and CB was observed (24.60% vs 2.11% vs 0.47 vs 1.97%). The clonogenic efficacy, as measured by CFU-C assays, was significantly higher in FBM when compared to ABM, PBMC and CB (202.5 vs 73.5 vs 40.81 vs 65.53/105 cells). There was a significant decrease in proliferative responsiveness when analyzed by MLR assays of FBM and CB as compared to ABM and PBMC (1X vs 4X vs 6.5X vs 6.3X). We further investigated the expression of hematopoietic-related cytokines in stromal cells from FBM, ABM, and CB. The expression of stem cell factor (SCF), GM-CSF, G-CSF, M-CSF, IL-3, IL-6, IL-10 and IL-11 was detected by using RT-PCR. Strong expression of SCF and IL-11 was observed in the stromal cells from FBM compared to ABM and CB. Although M-CSF was not detected in any of 8 FBM specimens, it was highly expressed in all ABM and CB stromal cells. IL-6 was detected in 6/8 ABM but only 1/8 in FBM and 0/7 in CB. G-CSF was not observed in CB, but it was expressed in all FBM and ABM specimens. In contrast, expression of GM-CSF, IL-3 and IL-10 by different sources of the stromal cells was similar. These results indicate that there are age-related changes in cytokine expression, and suggest that the expression of the cytokines at different maturational stages may play an important role in regulating differentiation and proliferation of the stem cells. This study may provide predicative information for treatment of hematologic diseases as well as selection of stem cells for transplantation.