Dynamic changes of chronic hepatitis B patient with loss of surface antigen: a case report

Hepatitis B virus (HBV) infection remains a significant global health challenge, particularly in regions like China, where the prevalence of HBV carriers is high. We report the dynamic serological and virological changes in a chronic HBV patient who exhibited HBsAg loss and subsequent reversion, explore the complex molecular mechanisms of atypical serological profile.

A 65-year-old male with a 40-year history of chronic HBV infection presented with hepatocellular carcinoma (HCC). Over three years, the patient underwent multiple interventions, including transarterial chemoembolization (TACE) and targeted therapies. Serial monitoring revealed a gradual decline in HBsAg levels, leading to seronegativity, followed by HBsAg reversion two years later. HBV DNA levels were quantified at 1.45 × 10³ IU/mL during HBsAg seronegativity. Genetic analysis identified multiple mutations in the HBV S gene, potentially altering HBsAg structure and antigenicity, contributing to the atypical serological profile.

This case underscores the complexity of HBV serological dynamics in the context of chronic infection and cancer treatment. The observed HBsAg fluctuations highlight the need for vigilant monitoring and advanced diagnostic techniques, such as HBV DNA testing, in patients with chronic HBV, particularly those undergoing immunosuppressive therapies. The identified S gene mutations may explain the serological changes, emphasizing the importance of genetic analysis in understanding HBV evolution and guiding clinical treatment.