Background: The significance of hepatitis B core antibody (anti-HBc) without hepatitis B surface antigen (HBsAg) or hepatitis B surface antibody (anti-HBs) is unclear.
Methods: This cohort study included men enrolled in the Multicenter AIDS Cohort to determine clinical and laboratory predictors of isolated anti-HBc.
Results: A total of 2286 subjects (51% human immunodeficiency virus [HIV]-infected) were followed over 3.9 years. Overall, 16.9% (387) had at least 1 visit with isolated anti-HBc. The isolated anti-HBc pattern was stable 84% of the time, and transitioned to or from a pattern of past infection (anti-HBc and anti-HBs). Isolated anti-HBc was associated with HIV infection (odds ratio [OR], 2.19; 95% confidence interval [CI], 1.73-2.79) and hepatitis C virus (HCV; OR, 4.21; 95% CI; 2.99-5.91). The HCV association was stronger for chronic HCV infection (OR, 6.76; 95% CI, 5.08-8.99) than for cleared HCV (OR, 3.03; 95% CI, 1.83-5.03). HIV infection, chronic HCV, and cleared HCV infection all remained associated with isolated anti-HBc in multivariable models (OR, 1.74; 95% CI, 1.33-2.29; OR, 6.24; 95% CI, 4.62-8.42; and OR, 2.77; 95% CI, 1.65-4.66, respectively). Among HIV-infected subjects, highly active antiretroviral therapy was negatively associated (OR, 0.79; 95% CI, .66-.95) with isolated anti-HBc.
Conclusions: Isolated anti-HBc is associated with HIV and HCV coinfection, especially active HCV replication, and most commonly occurs as a transition to or from the pattern of natural immunity (anti-HBc and anti-HBs). The isolated anti-HBc pattern likely represents resolved HBV infection with low or undetected anti-HBs.