The kinetics of the hepatitis B surface antigen level after the initiation of antiretroviral therapy for hepatitis B virus and human immunodeficiency virus coinfected patients

Background: Hepatic flares (HF), which reflect hepatitis B virus (HBV)-related immune reconstitution inflammatory syndrome (IRIS), frequently occur in patients with HBV and human immunodeficiency virus (HIV) coinfection after the start of antiretoroviral therapy (ART). The rate of hepatitis B envelope antigen (HBeAg) and hepatitis B surface antigen (HBsAg) loss is higher for patients with HF after the initiation of ART. Methods: We retrospectively examined the kinetics of the HBsAg and HBeAg levels of six HBV/HIV coinfected patients after the commencement of ART that included tenofovir. All were male and HBeAg positive. Results: Three patients developed HF after the initiation of ART. All subsequently lost HBeAg and one of them lost HBsAg after HF. None who did not experience HF lost HBeAg. The HBsAg and HBeAg levels remarkably decreased when HF occurred, but the decline of HBsAg was very slow in the periods before and after HF. The median decline of the HBsAg level at 48 weeks was 2.20LogIU/mL for patients with HF,but only 1.00LogIU/ml for patients without HF. Little decline was seen for either group in the median decline of the HBsAg level from 48 weeks to 96 weeks, 0.28LogIU/mL in the HF group and 0.06 Log IU/mL in the non-HF group. Conclusion: The immune reconstitution of a HBV/HIV coinfected patient plays an important role in the clearance of HBV. If HBsAg and HBeAg levels decrease rapidly when HF occurs, the hepatic flare would be due to HBV-related IRIS.