Long-term presence of HBV in the sera of chronic hepatitis B patients with HBsAg seroclearance

OBJECTS: The aim of this study was to elucidate the presence of serum hepatitis B virus (HBV) DNA at a prolonged time after seroclearance of hepatitis B surface antigen (HBsAg). METHODS: Seventy Japanese patients who had been observed for >5 years after HBsAg seroclearance were included in this study. Anti-HBs, anti-HBe and anti-HBc antibodies were measured 0, 5 and 10 years after HBsAg seroclearance. Serum HBV DNA was measured using nested polymerase chain reaction (PCR) at 0, 5 and 10 years after HBsAg seroclearance. The PCR detection of serum HBV DNA using the X gene and core gene primers was done. The HBV DNA was regarded as positive when PCR detection of HBV DNA using either or both the X gene and core gene primers was positive. A multivariate regression analysis was used to assess the factors contributing to the positivity of serum HBV DNA 5 years after HBsAg seroclearance: the factors examined included age, gender, histological findings, HBV genotype, aminotransferase, total protein and interferon administration. RESULTS: The titers of 200-fold diluted serum anti-HBc were 6.5 +/- 4.0 at 0 year after HBsAg seroclearance, 1.8 +/- 1.4 at 5 years and 0.9 +/- 0.7 at 10 years. The titers of 200-fold diluted serum anti-HBc decreased 5 and 10 years after HBsAg seroclearance with statistical significance. The positive rate of HBV DNA by the nested PCR was 71.4% (50/70) at 0 year after HBsAg seroclearance, 21.4% (15/70) at 5 years and 14.3% (3/21) at 10 years. However, there were no significant factors contributing to the positivity of serum HBV DNA 5 years after HBsAg seroclearance. CONCLUSION: Our results suggest that serum HBV DNA disappears with an incidence of 10-20% 5 and 10 years after HBsAg seroclearance.