Hepatitis B virus (HBV) reactivation after cytotoxic or immunosuppressive therapy - pathogenesis and management

In an endemic area for chronic hepatitis B infection, reactivation of this virus is a serious cause of morbidity and mortality in patients undergoing cytotoxic or immunosuppressive therapy. Careful prospective serological tes ting has shown that hepatitis B virus reactivation is a two-staged process. The initial stage occurs during intense cytotoxic or immunosuppressive the rapy and is characterised by enhanced viral replication, as reflected by in creases in the serum levels of hepatitis B virus DNA, hepatitis B e antigen , hepatitis B virus DNA polymerase and infection of naive hepatocytes with hepatitis B virus. The second stage is related to restoration of immune fun ction following withdrawal of cytotoxic or immunosuppressive, therapy, whic h causes rapid immune-mediated destruction of infected hepatocytes. Clinica lly, this can lead to hepatitis, hepatic failure and even death. The occurr ence and severity of hepatitis B virus reactivation after various cytotoxic or immunosuppressive therapy is unpredictable and treatment has been disap pointing, largely due to the late administration of therapy. Recently, pre- emptive treatment of chronic hepatitis B patients undergoing cytotoxic or i mmunosuppressive therapy, with potent nucleoside analogues has shown some p romising results. Further controlled studies are needed to define the incid ence and risk factors of hepatitis B reactivation so that pre-emptive treat ment with nucleoside analogues could be administered to those patients at h igh risk of disease. Copyright (C) 2001 John Wiley & Sons, Ltd.