[Hepatitis C virus infection in renal diseases: state of knowledge, therapeutic problems and perspectives].

Chronic infection with hepatitis C virus (HCV) is estimated to affect almost 170 million individuals worldwide. 20-30% of these individuals develop cirrhosis and its sequelae. Only 15-20% of patients with chronic hepatitis C achieve a sustained virological response to interferon monotherapy. The prevalence of anti-HCV antibodies in dialysis patients varies between 1% and 29% in Western Europe. In patients with ESRD on maintenance HD therapy, in whom a blunted immune response per se is observed, the usefulness of IFN-alpha therapy is usually discussed in the context of subsequent transplantation associated with intensive immunosuppressive treatment regimens. A recent study has shown that in this patient group renal transplantation is associated with a fivefold increase in posttransplantation liver disease as well as a relative risk of death of 3.3 compared to HCV-negative patients. Thus, eradication of HCV infection in patients with ESRD may substantially reduce morbidity and mortality in renal allograft recipients. The imbalance of T-helper (Th) lymphocyte cytokine production may play an important role in the immunopathogenesis of chronic HCV infection. Little is known about the effects of IFN-alpha therapy on Th1/Th2 activity in HD patients. The type of immune response against infectious agents is determined in part by the pattern of cytokines secreted by T lymphocytes. Th1 cells promote cellular immunity against infectious agents, while Th2 cells induce humoral immune response and immune tolerance activity. The measurement of Th1/Th2 profile should increase our understanding of the immune status of patients with HCV infection. Therefore, the recently presented studies were undertaken to evaluate the influence of IFN-a therapy on Th1/Th2 balance in HD patients with chronic HCV infection.