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.
Keywords: IL-28B gene polymorphism; chronic hepatitis C; genotype 2.
© 2013 The Japan Society of Hepatology.