Abstract: Objective To investigate the impact of cytotoxic T lymphocyte（CTL） epitope mutation of HBV envelope and core protein on disease progress in patients with hepatitis B. Methods 38 individuals with asymptomatic HBsAg carrier,35 patients with chronic hepatitis B and 23 with liver cirrhosis were recruited in this study. Gene sequencing analysis of HBV core region and envelope region was carried out in all enrolled patients to unveil any possible CTL epitope mutation. Results The mutation rates of locus 41~49,88~96,97~108,172~180 and 185~194 of CTL epitope in HBV envelope region were 48（55.2%）,13（14.9%）,11（12.6%）,9（10.3%） and 6（6.9%）,respectively;60% of mutation at locus 41~49 in patients with chronic hepatitis B and 65.2% in with liver cirrhosis were significantly higher than 31.6% in asymptomatic HBsAg carriers（P<0.05）;the mutation rates at 18~27 and 91~95 locus of CTL epitope in HBV core region were 56.2% and 43.8%,respectively;the mutation rates at locus 18~27 were also higher in patients with CHB（20.0%） and LC（30.4%） than that in asymptomatic HBsAg carriers （10.5%,P<0.05）;Multivariate analysis showed that locus 41~49 mutation was an independent risk factor for the progress of CHB to LC. Conclusion CTL epitope mutation of HBV is a significant cause for the chronicity of hepatitis B virus infection.

Key words: Hepatitis B, Mutation, Cytotoxic T lymphocytes, Epitope