Host genetic factors influencing the outcome of hepatitis.

A strong genetic component determining the outcome of hepatitis B virus (HBV) infection has been established through twin studies. The immunopathogenesis of HBV infection is well described and it has therefore been possible to predict some gene loci, exhibiting polymorphism, may influence the outcome of HBV infection. As expected, the immune response genes in the major histocompatibility complex (MHC) on the short arm of chromosome 6 have provided confirmed susceptibility genes. In hepatitis C virus (HCV) infection the picture is not so clear although comparison of the known immunological phenomena with those of HBV suggest that polymorphisms in the MHC may also influence disease outcome. Identification of susceptibility genes, which modify disease phenotype, may assist in predicting natural outcome of infection or response to therapy.