Hepatitis B virus genotype distribution among chronic hepatitis B virus carriers in Shanghai, China

OBJECTIVE: Hepatitis B virus (HBV) genotype distribution is still unclear in China, where a high prevalence of HBV infection exists, although it is well known that HBV can be classified into six genotypes based on intergroup divergence. The aim of this study was to investigate the epidemiological distribution of HBV genotypes and to clarify further the genotype-related differences in the pathogenicity of HBV. METHODS: Seminested PCR and restriction fragment length polymorphism analysis were conducted in 97 asymptomatic HBV carriers (ASC) and 46 chronic hepatitis (CH), 37 liver cirrhosis (LC) and 44 hepatocellular carcinoma (HCC) patients in Shanghai, China. RESULTS: Two hundred and twenty samples (98.2%) were positive for HBV DNA, and of these, 3 (1.4%), 38 (17.2%) and 179 (81.4%) were classified as genotype A, B and C, respectively. There was a statistically significant difference in the distribution of genotypes B and C among various categories of liver diseases (p < 0.01). The distribution of genotype C showed an increasing trend from ASC, CH and LC to the HCC group; in contrast, the distribution of genotype B showed a decreasing trend in the same order. HBeAg positivity was higher in genotype C than in genotype B in all the subjects or in the ASC group alone (p < 0.05, p < 0.01, respectively). More severe liver damage and a higher mean age were observed in genotype C than in genotype B (p < 0.01, p < 0.05, respectively). CONCLUSIONS: These results indicate the following: (1) genotypes A, B and C of HBV exist in Shanghai, China; (2) genotype C is the major genotype in this area; (3) genotype C is associated with the development of severe liver diseases, and (4) genotype B has a relatively good prognosis.