Immunity in Different Types of Hepatitis C

Hepatitis C virus (HCV) represents serious threat for human health due to a very high probability for developing chronic liver diseases. The virus has a number peculiarities, which helps him to escape elimination by neutralizing antibodies and immune cells. The main of them are high frequency of the amino acid substitutions within certain immunogenic parts of the viral proteins, the quasispecies nature of the virus, specific functions of the viral proteins, directed against antiviral effects. During acute phase of hepatitis C patients usually have expressed humoral and cellular responses. But only 15% of them have resolved infection. Unfavourable prognostic indications were considered to be high titers of antibodies against NS3 and NS5 proteins, low levels of Th and CTL cell responses, and probably low level of serum 2',5'- oligoadenylate synthetase at the end of acute phase of hepatitis C. Recently it has been shown the existence and significance on E2 protein NOB epitopes, antibodies to which neutralize the virus binding to cells. A lot of CTL- and Th-epitopes were mapped on the viral antigens. Efficiency of humoral and cellular immune response during chronic hepatitis C is limited. Persisting HCV infection may lead to development B-cell lymphoproliferative disorders such a mixed cryoglobulinemia, non-Hodgkin's lymphoma, and to appearence organ-specific and non-organ-specific autoantibodies.