Immunopathogenesis of Hepatitis B Virus (HBV) Infection

Though HBV itself is not cytopathic, the host immune responses associated with HBV infection determine the outcomes of HBV infection, either acute or chronic infection. Innate and adaptive arms of the immune system are usually involved in combating viral infection. During acute HBV infection, innate immunity is important for control of viral replication and dissemination at very early stage after HBV infection; subconsequently, adaptive immunity, especially vigorous, multi-specific and long-lasting HBV-specific T cellular immunity can further efficiently control viral infection. However, dysfunction is the hallmark of adaptive immunity during chronic infection, including faint humoral immunity and exhausted T cellular immunity. Host immune responses induced by HBV infection not only substantially drive disease progression, but also significantly influence efficacy of antiviral treatments in chronic HBV-infected individuals. Therefore, it is important to fully understand the course of immune pathogenesis and to find efficient immunotherapy plus nucleoside analogue(NUC) or IFN-α treatment to completely eliminate or functionally cure HBV infection. In this chapter, we summarizes the current progress in innate and adaptive immunities during acute or chronic HBV infection in humans.