HBV, Hepadnaviridae family, not direct cytopathic. This hepatocellular lesion is the result of an immunological response to viral antigens. A very aggressive response causes fulminant hepatitis. In chronic cases there is a weak response from lymphocyte T cell CD 8 and predominates the humoral response of TH-2 (IL-4-5-10) substances. Factors that affect the evolution: virus mutation, co-infection with other viruses, immune status of the patient. Stages of the evolution towards chronicity: a) immunotolerant stage (abundance of virus and e positive, seroconversion lasts years; seroconversion of Ag is 15% in 20 years); b) immune clearance stage (seroconversion of Ag is 10-20% per year); c) inactive carrier stage (most patients are chronic, Antigen negative and anti e positive); d) chronic hepatitis e negative (high DNA with an increase of ALT, most of them are core and pre-core mutations and do not produce antigen); e. resolution of chronic infection (0.5-2% clear the surface antigen, but in the future they could cause liver cell carcinoma because they are anti-HB positive

acute infection type B virus; chronic infection type B virus; HBV; inmunopathogenesis