Background and aim: Response to hepatitis C virus (HCV)-specific therapy is variable but might be influenced by host factors. We studied whether interleukin-6 (IL-6) level, IL-6–174G>C gene polymorphism, and insulin resistance affect the response to antiviral treatment in HCV-infected patients.

Patients and methods: Fifty-five chronic hepatitis C patients and 13 healthy individuals as controls were included in this study. Liver function tests, HCV RNA titer, ultrasonography, and histopathological examination of liver tissues were performed for all patients. Pretreatment plasma IL-6 levels and homeostasis model assessment-insulin resistance were estimated. The IL-6–174G>C polymorphism was detected by the PCR/RFLP method. After 12 weeks of combined pegylated interferon-α and ribavirin therapy, patients were classified into responders or nonresponders according to whether they achieved an early virological response.

Results: The responders had significantly high IL-6 levels (P=0.01), low mean stage of fibrosis (P=0.03), and low viral load (P=0.04) compared with nonresponders. Although not significant, patients with the IL-6–174 CC genotype reported a higher response rate (81%) compared with those with the CG genotype (50%) and GG genotype (62%). IL-6 level at a cutoff point of 2.15 pg/ml had 81.1% sensitivity and 72.7% specificity and showed significant relation with early virological response (P=0.04).

Conclusion: Estimation of basal IL-6 level could be used as a predictor of response to pegylated interferon-α and ribavirin therapy in CHC patients.