Abstract: Objective To investigate the expression of Fas antigen and Fas ligand（FasL） in liver tissues from chronic asymptomatic hepatitis B virus （HBV） carrier （ASC）. Methods Liver biopsy specimen and sera from 120 individuals with ASC were obtained;The expression of Fas and FasL in liver tissues were detected by immunohistostaining. Serum levels of soluble Fas （sFas） and sFasL were measured by ELISA. Results Only 11% had a normal appearance of liver tissues in the 120 chronic HBV carriers,and 59% had mild and other 30% had moderate to severe hepatitis;Fas and FasL were negative in normal liver tissues,almost absent or only slightly positive in hepatocytes and lymphocytes in inflammatory zone of the interface in liver tissues with mild hepatitis,and strongly positive in those with moderate or severe hepatitis,showing a pattern of diffused staining in the interface area of hepatic lobules;The strongly positive rate for Fas and FasL in moderate（34.8% and 30.4%,respectively） and severe hepatitis（69.2% and 53.8%,respectively） was significantly higher than that in mild hepatitis or normal liver tissues（P<0.05）;Serum sFas from persons with normal liver tissues was（1.68±0.33） ng/L,and they increased significantly to（2.58±0.31） ng/L,（3.94±0.21） ng/L and（5.94±0.26） ng/L,respectively,from individuals with mild,moderate and severe hepatitis（P<0.01）. Conclusion The Fas-FasL mediated apoptosis might play an important role in the disease progress of ASC.

Key words: Chronic asymptomatic hepatitis B virus carrier, Apoptosis, Fas, Fas ligand