Résumé
PURPOSE: Umbilical cord blood (CB) transplantation is an alternative method instead of allogeneic bone marrow (BM) transplantation. CB transplantation has used grafts with red blood cell (RBC) depletion but previous reports in CB investigated the immune reaction about mononulcear cell separated by density gradient. To study the real immune response in CB transplantation, the experimental group designed the total nuclear cell (TNC) groups by RBC depletion and the mononuclear cell (MNC) groups by Ficoll Hypaque in CB and BM. METHODS: We evaluated the various cytokine gene expression by semiquantitative RT- PCR method after immune stimulation with phytohemagglutinin in cord blood and bone marrow according to cell separation method. RESULTS: 1) All samples of CB and BM expressed IL-2 mRNA. There was no difference in amounts of IL-2 mRNA between CBTNC and CBMNC, between BMTNC and BMMNC. 2) All samples of CB and BM expressed IL-10 mRNA. There was no difference in amounts of IL-10 mRNA between the CBTNC and CBMNC but significantly different between the BMTNC and BMMNC (P<0.05). The amounts of IL-10 mRNA in the BMMNC and CBTNC group showed larger than in the BMTNC group (P<0.05). 3) The expression of IL-4, IFN-gamma was not shown in this study. These results suggest that no difference of IL-2 mRNA between CB and BM may reveal IL-2 as major cytokine gene in CB after immune stimulation. The expression of IL-10 mRNA in CBTNC showed more than in BMTNC group. Conclusion: Our results suggest that CBTNC may contain a lot of cells producing IL-10, as a cytokine of immunoregulatory function, and therefore the immune reaction in CB transplantation may be less apparent than in BM transplantation. The cell component producing IL-10 in CB may be T regulator cell. There were not showed the IFN-gamma and IL-4 mRNA due to short duration of immune stimulation. Therefore, further studies will identify the IL-4 and IFN-gamma mRNA expression after long time stimulation and various cytokine gene expression to certificate the precise immune response after flow cytometry to composed of immune cells in CB and BM.