Influence of hepatitis delta virus superinfection on the clearance of hepatitis B virus (HBV) markers in HBV carriers in Japan

To elucidate the influence of hepatitis delta virus (HDV) superinfection on the clearance of hepatitis B virus (HBV) associated antigens in HBV carriers, we examined for antibody to hepatitis delta antigen (anti-HD) serial sera collected from 1,029 HBV carriers in Kure, Japan. Of the 242 HBV carriers with hepatitis B e antigen (HBeAg), 28 became seropositive for anti-HD, of whom 18 (64.3%) cleared HBeAg; 214 did not become seropositive for anti-HD, of whom 70 (32.7%) cleared HBeAg. Thus, HBeAg clearance was observed in a significantly higher proportion of HDV-superinfected carriers as compared with carriers without HDV infection (P less than 0.005). In the 56 HBV carriers who cleared hepatitis B surface antigen (HBsAg), anti-HD was detected in three cases with increased serum alanine aminotransferase activity preceding HBsAg clearance. The duration of anti-HD seropositive state was less than 5 years, and the titer of anti-HD was relatively low in every case. These data suggest that the HDV infection rate in Japan is higher than previously reported, that HDV superinfection can be one of the factors that induce the HBeAg clearance and HBsAg clearance in HBV carriers, and also that the most likely outcome of HDV superinfection in HBV carriers in Japan may be acute self-limited infection.