Abstract: The objective of the study was to investigate Fas antigen induced apoptosis in the pathogenesis of aplastic anemia. The expression of Fas antigen on bone marrow CD34⁺ cells and the effect of IFN-γ to it were assayed in AA by flowing cytometry and short-liquid-culture in vitro. Fas antigen expression on CD34⁺ cells in SAA and CAA was significantly higher than that in normal controls 〔(38.28± 9.01)% and(26.66±4.27)% vs(10.02±2.33)%, (P<0.01, (P<0.05 respectly〕. Fas antigen expression on CD34⁺ cells in CAA was significantly lower than that in SAA(P<0.05). Addition of IFN-γ to liquid culture of BMMNC including SCF, IL-3, GM-CSF and EPO cytokines showed significant stimulating effects on Fas antigen expression in AA, but not in normal controls, the expression in SAA was higher than that in CAA(P<0.05). The abnormal expression of Fas antigen on CD34⁺ cells may be involved in the pathogenesis of AA.

Key words: anemia|aplastic|CD95|IFN-γ|apoptosis