Review article: hepatitis B core‐related antigen ( HB HB crAg): an emerging marker for chronic hepatitis B virus infection

摘要

Summary Background Chronic hepatitis B ( CHB ) cannot be completely eradicated due to the presence of covalently closed circular DNA (ccc DNA ) in the nuclei of infected hepatocytes. While quantification of intrahepatic ccc DNA requires liver biopsies, serological markers can be non‐invasive alternatives to reflect intrahepatic viral replicative activity. Recently, hepatitis B core‐related antigen ( HB crAg) has been advocated as a novel serum marker for disease monitoring and prognostication of CHB . Aim To examine the virological aspect and clinical application of HB crAg with respect to the natural history and treatment of CHB . Methods We reviewed all papers published in the PubMed journal list and abstracts from major international meetings that included the keyword “ HB crAg” or “hepatitis B core‐related antigen” until March 2017. Selected studies were compared and summarised on the basis of existing theories, as well as the authors’ experience. Results HB crAg exhibited good correlation with intrahepatic (ih) ccc DNA , ih total hepatitis B virus ( HBV ) DNA , serum HBV DNA and to a lesser extent HBV surface antigen ( HB sAg). In situations where serum HBV DNA levels become undetectable or HB sAg loss is achieved, HB crAg can still be detectable. This marker is helpful in differentiation of HB eAg‐negative chronic hepatitis from HB eAg‐negative chronic infection, predicting spontaneous or treatment‐induced HB eAg seroconversion, sustained response to nucleos(t)ide analogue ( NA ), risk of HBV reactivation in occult HBV infection under immunosuppressive therapies, and risk of hepatocellular carcinoma ( HCC ) development as well as post‐operative HCC recurrence. Conclusions HB crAg is a potential surrogate marker of ccc DNA . It may soon become a useful marker for disease monitoring, predicting treatment response and disease outcome of chronic hepatitis B.