Natural seroconversion from hepatitis Be antigen to antibody among hepatitis B virus carriers in Okinawa Islands

In the Okinawa Islands, the great majority of hepatitis B surface antigen (HBsAg) carriers have already acquired antibody to hepatitis Be antigen (anti-HBe) by the age of 30 years (preliminary cross-sectional data). To elucidate natural seroconversion from hepatitis Be antigen (HBeAg) to anti-HBe among HBsAg carriers found in the islands of Okinawa Prefecture, 34 HBeAg-positive HBsAg carriers were followed for 1-6 years with serial measurements of aminotransferase levels, HBeAg, and anti-HBe. The 34 subjects included 24 patients with chronic hepatitis (group 1) and ten asymptomatic HBsAg carriers (group 2). During the follow-up period, HBeAg disappeared from 14 subjects in group 1 with the cumulative clearance rate of HBeAg of 56.3% within the first 2 years and with 10 of the 14 subsequently developing anti-HBe. Moreover, the aminotransferases in 12 of the 14 spontaneously seroconverted fell into the normal range. The annual clearance rates of HBeAg among group 1 and group 2 were 25.6% and 9.3%, respectively. The tendency for early disappearance of HBeAg during a carrier's life time or in the course of chronic hepatitis may lead to the low death rate from hepatocellular carcinoma (HCC) particularly HCC associated with hepatitis B virus infection in this area.