Rethinking the pathogenesis of hepatitis B virus (HBV) infection

Chronic hepatitis B virus (HBV) infection affects approximately 375 million people worldwide. Current antiviral treatment effectively controls, but rarely clears chronic HBV infection. In addition, a significant portion of chronic HBV infected patients are not suitable for currently available antiviral therapy, and still face higher risk for cirrhosis and hepatocellular carcinoma. The poorly understood pathogenesis of HBV infection is the main barrier for developing more effective treatment strategies. HBV has long been viewed as non-cytopathic and the central hypothesis for HBV pathogenesis lies in the belief that hepatitis B is a host specific immunity-mediated liver disease. However, this view has been challenged by the accumulating experimental and clinical data that support a model of cytopathic HBV replication. In this article we systematically review the pathogenic role of HBV replication in hepatitis B and suggest possible HBV replication related mechanisms for HBV-mediated liver injury. We propose that a full understanding of HBV pathogenesis should consider the following elements. I. Liver injury can be caused by high levels of HBV replication and accumulation of viral products in the infected hepatocytes. II. HBV infection can be either directly cytopathic, non-cytopathic, or a mix of both in an individual patient depending upon accumulation levels of viral products that are usually associated with HBV replication activity in individual infected hepatocytes.