Effects of IL‐28B gene polymorphism on response to peginterferon plus ribavirin combination therapy for genotype 2 chronic hepatitis C. Issue 9 (2nd January 2013) - Shimoyama, Yu
Abstract : Aim: Interleukin ( IL ) ‐28B gene polymorphism is closely linked with treatment response to peginterferon plus ribavirin combination therapy for hepatitis C virus genotype 1. However, few studies have reported its effects on therapy for genotype 2. We aimed to examine the effects of IL‐28B gene polymorphism on treatment response in hepatitis C virus genotype 2 patients. Methods: In a retrospective study of 101 patients infected with either genotype 2a ( n = 65) or 2b ( n = 36) and treated with peginterferon plus ribavirin, we investigated predictive factors for a sustained virological response (SVR), including genetic variations near the IL‐28B gene (rs8099917, rs11881222 and rs8103142) and clinical variables such as age, sex, body mass index, stage of fibrosis and drug adherence. Results: Ultra‐rapid virological response, rapid virological response (RVR), end‐of‐treatment response, SVR and relapse rates were 22.2%, 61.4%, 95.0%, 87.1% and 7.9%, respectively. In univariate analysis, RVR and IL‐28B single nucleotide polymorphisms (SNP) (rs8099917, rs11881222 and rs8103142) were significantly associated with SVR. In subgroup analysis, IL‐28B SNP were significantly associated with SVR in genotype 2a patients but not in genotype 2b patients. In multiple logistic regression analysis, RVR and IL‐28B SNP (rs8099917) were independently associated with SVR. Furthermore, IL‐28B SNP was significantly associated with relapse but RVR was not. Conclusion: In genotype 2 patients treated with peginterferon plus ribavirin combination therapy, IL‐28B gene polymorphism was a significant independent predictor of SVR as well as RVR. IL‐28B major allele may favor reduced relapse rates in patients with genotype 2 chronic hepatitis C.