Proapoptotic IL-18 in patients with chronic hepatitis C treated with pegylated interferon-alpha

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide. In mainland of China, It was estimated the population of 1.3 billion infected with HCV. HCV is not cytopathic. Immune response that is essentially conducted by cytokines may play an important role in the pathogenesis of HCV infection. Interleukin (IL)-18, mainly produced by monocytes/macrophages, plays an important role in the immune system by enhancing T cell responses, regulating interferon-gamma (IFN-γ) production and promoting the development of T helper cell Th1 immune responses. Raised serum levels of IL-18 have recently been reported in patients with chronic hepatitis C before antiviral therapy. Herein we report the IL-18 sequential changes in patients with hepatitis C during the period of pegylated interferon (PEG-IFN) alpha treatment for 48 weeks. We established the correlation of plasma IL-18 level and alanine aminotransferase (r = 0.77, P < 0.05). Hepatic inflammatory activity in chronic hepatitis C was shown to be closely associated with an increased amount of IL-18. HCV-infected patients had raised IL-18 levels (93.67 ± 23.58 pg/ml versus 59.73 ± 24.06 pg/ml; P < 0.001) comparing donor negativity for HCV. PEG-IFN alpha-2a treatment induces a marked decline in IL-18 and remission of hepatic inflammatory in responders at week 24 and week 48 follow-up time point, while increased levels persist in those in whom the HCV infection was not eliminated by the therapy. We proposed declined IL-18 levels favor for virus solution, while persistent raised IL-18 associated with PEG-IFN treatment failure.