Prevalence of HBV genotypes in asymptomatic carrier residents and their clinical characteristics during long-term follow-up: the relevance to changes in the HBeAg/anti-HBe system.

Randomly selected 50 asymptomatic hepatitis B virus (HBV) carrier residents who had been followed annually were enrolled in this study. The subject group comprised 25 males and 25 females with a mean age at the start of follow-up of 44.1+/-10.4 years. The mean follow-up period was 15.5+/-2.7 years. Genotyping revealed 27 (54%) of genotype B and 23 (46%) of genotype C. The prevalence of genotype B was clearly higher in asymptomatic HBV carrier redidents, which was contrary to the previous reports on chronic liver disease. At the start of follow-up, the ratio of carriers positive for anti-HBe was significantly higher in genotype B than genotype C (P<0.001). Furthermore, the ratio of carriers with reduced HBV-DNA levels was significantly higher in genotype B than genotype C (P<0.01), suggesting that most genotype B carriers had already undergone seroconversion from HBeAg to anti-HBe and were clinically stable at the start of follow-up. The subsequent follow-up observations demonstrated that levels of HBV-DNA and ALT were lower in genotype B than genotype C. Seroconversion from HBeAg to anti-HBe was less likely to occur in genotype C carriers, especially on 40-year-old generation, and these subjects were more likely to develop chronic liver disease.