[Spontaneous reactivation of hepatitis B virus in an elderly patient: a case report and review of the literature].

Reactivation of resolved hepatitis B virus (HBV) infection without any immunosuppressants has rarely been reported. Here, we describe the spontaneous HBV reactivation in a 78-year-old male patient with resolved HBV infection. Twenty-five years ago, he received interferon treatment for chronic hepatitis C. Concurrently, he was negative for HBsAg and positive for anti-HBcAb, and he achieved a sustained virological response (SVR). He developed hepatitis B infection without any cause at the age of 78 years. His serum was positive for HBsAg, HBeAg, and HBV DNA (4.9logIU/ml;genotype B), but negative for anti-HBc IgM and HCV RNA. A liver biopsy revealed A2F1. His serum HBsAg and HBV DNA levels became negative 2 months and 6 months after entecavir treatment, respectively. HBcrAg, the last remaining HBV marker, became negative after 2 years, and ETV treatment was completed after 27 months. No HBV reactivation was observed 4 years after the end of treatment. Full-genome HBV sequence analysis indicated that the patient was infected with HBV of subgenotype B1 and had no mutations in the S, the core promoter, and pre-core regions. This case developed de novo hepatitis B without any immunosuppressants, indicating that aging may have been responsible for the spontaneous HBV reactivation. Additionally, in this report, we summarized the reported cases of reactivation of resolved hepatitis B in elderly patients with no previous triggers.