658 LOWER HEPATITIS B VIRUS PRODUCTIVITY IN THE HBeAg-NEGATIVE PHASE IS NOT DUE TO THE EMERGENCE OF VIRAL MUTATIONS WITHIN REGULATORY REGIONS

Background and Aims: Combined, hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are the most prevalent causes of chronic liver disease globally.In Taiwan, HBV infection usually occurs in the perinatal period or early childhood, while HCV infection occurs later in life.Clinical data obtained from chronic HBV carriers superinfected with HCV suggest that active HCV infection may inhibit HBV replication.In these analyses we evaluated this issue.Methods: The study subjects for these analyses were derived from a subset of the REVEAL-HBV cohort study.Only subjects with complete HBsAg, anti-HCV, and alanine aminotransferase (ALT) from entry serum samples were included in these analyses.HBV DNA and HCV RNA levels were tested in HBsAg-positive and anti-HCV antibody positive subjects respectively.Among subjects co-infected with both viruses, the relationship between the HBV DNA and HCV RNA levels was evaluated first by correlation analyses, and then by a multivariable linear regression model adjusting for age, gender, and serum ALT level.Results: Of the 23,820 subjects in the cohort, 23,785 completed HBsAg and anti-HCV tests.Of these, 3,931, 1,095, and 218 subjects were infected with HBV alone, HCV alone, and co-infected with HBV and HCV, respectively.The prevalence of anti-HCV positivity was 5.6% and 5.3%, respectively, for HBsAg-seropositive and -seronegative persons (p = 0.41).HBV DNA was detectable in 76% of anti-HCV-negative subjects compared to 60.5% of the anti-HCV-positive subjects (p < 0.001); the mean±SD for log HBV DNA levels in copies/mL were 3.62±2.5 vs. 2.74±2.6.HBV DNA and HCV RNA were tested in 181 of 218 co-infected persons.In this group, HBV and HCV viral loads were negatively correlated (r = -0.26;p < 0.001).After adjustment for gender, age, and ALT levels in the multivariable linear regression analysis, serum HBV DNA level increased with decreasing serum HCV RNA level (r = -0.24;p < 0.001). Conclusions:The results of this study suggest a likely interference in the replication levels of HBV and HCV rather than in the seroprevalence of HBsAg and anti-HCV.In Taiwan where the superinfection of HCV comes later, HBV replication may be negatively influenced by the replication of HCV.