Advance in the natural history of hepatitis B virus infection.

The dynamic balance between viral replication and the host immune response plays a key role in the natural history and pathogenesis of hepatitis B virus infection.Most infections in immunocompetent adults are self-limited,whereas most infants develop chronic HBV infection.Chronic HBV infection may present in four phases: immune tolerance,HBeAg-positive chronic hepatitis,non-replicative HBsAg carriers and HBeAg-negative chronic hepatitis.Several risk factors,such as HBV DNA levels,HBeAg status,and ALT levels,have been identified to predict the long-term outcome,including cirrhosis and HCC.Stages of the natural history of HBV infection,outcome and prognosis of chronic HBV infection are reviewed in this paper.