Reactivation of hepatitis B: pathogenesis and clinical implications.

Chronic hepatitis B virus (HBV) is estimated to be present in 350 million people worldwide. One of its major complications is reactivation of dormant HBV, which is associated with significant morbidity and mortality. Although reactivation can occur spontaneously, the most common risk factor is initiation of immunosuppression. As the use of immunosuppressive therapy increases, the incidence of HBV reactivation is expected to rise. Screening with serologic markers for hepatitis B is recommended before initiating immunosuppressive therapy. In patients with no evidence of HBV infection, immunization is recommended. In chronic carriers, prophylactic antiviral treatment has been shown to decrease overall morbidity and mortality. Patients with inactive HBV should be monitored closely during immunosuppressive treatment with alanine transaminase and serum HBV-DNA levels and treated promptly if they develop HBV reactivation. Although HBV reactivation is a serious complication, it can be prevented with screening and prophylactic treatment.