BACKGROUNDIt has been known that intra-cellular immunity is important for defense against viral infections and this function lies with interferon gamma (INF-gamma). Here we evaluated the role of IFN-gamma system in the pathogenesis of chronic hepatitis C (CHC).

METHODSThe levels of interferon gamma receptor alpha (IFNGR alpha) on the peripheral lymphocyte membrane were assayed with flow cytometry. The plasma concentrations of the cytokines IFN-gamma and IL-10 in CHC patients and normal controls were assayed by enzyme-linked-immunosorbent assay (ELISA). The samples were collected randomly from Xinjiang Autonomous Region, Zhejiang and the northern regions of Jiangsu Province in China.

RESULTSThe levels of IFNGR alpha in CHC patients were significantly lower than that of normal controls (NC), especially among patients during the stable stage (P < 0.001), whereas there were no significant differences between CHC in active and stable stages. Among the patients of the three regions, there were no significant differences between patients from Xinjiang and Zhejiang provinces, but both had statistically significant difference compared with the patients from Jiangsu Province (P < 0.001). Plasma IFN-gamma and IL-10 concentrations in CHC patients decreased significantly, IFN-gamma in particular, but there were no significant differences in these levels between various stages of the disease. The IFN-gamma/IL-10 (Th1/Th2) ratio in patients was reversed.

CONCLUSIONThere may be defects in the IFN-gamma system in chronic HCV infected subjects and a low immune response, which may play an important role in the persistence of HCV infection.