Impact of host gene polymorphisms on susceptibility to chronic hepatitis B virus infection.

Hepatitis B virus (HBV) infection can result in a number of different clinical conditions, including asymptomatic HBV carriers to chronic hepatitis and primary hepatocellular carcinoma. Variations in cytokine genes have been discussed to affect the natural history of HBV infection. These cytokines may involve in the viral binding to the cells, modulating the host immune response to infection and pathological changes in the liver, and affecting the antiviral therapies. Various studies reveal that SNPs play an important role in pathogenesis of HBV. On the other hand, various outcomes of infection cannot be completely shown by genetic factors because these studies have inconsistent results with regard to the possible impacts of host genetic polymorphisms on susceptibility to infection. Therefore, to identify the real effects of host genetic factors in HBV susceptibility and natural history of the disease, studies with large sample size will be needed. In addition, due to the complex interactions of genetic factors it is better to identify synergies of several SNPs. Such studies can provide better insights into the novel methods of diagnosis and treatment. Current review will discuss significant genetic variations in cytokine genes that may affect the susceptibility to the chronic HBV infection.