The impact of genetic variation in IL28B, IFNL4 and HLA genes on treatment responses against chronic hepatitis C virus infection

Single nucleotide polymorphisms (SNPs) near the interleukin-28B (IL28B), interferon lambda 4 (IFNL4) and the human leukocyte antigen (HLA) gene are associated with treatment responses in patients with chronic hepatitis C (CHC) virus infection treated with pegylated interferon-a and ribavirin (pegIFN-a/RBV). We compared the role of IL28B SNPs (rs12979860, rs12980275, and rs8099917), IFNL4 ss469415590 and HLA rs4273729 with treatment outcomes in patients with CHC virus. A total of 520 Iranian patients with CHC infection were enrolled. SNPs in IL28B, IFNL4 ss469415590 and HLA rs4273729 were genotyped by PCR-restriction fragment length polymorphism, TaqMan (R) Real-Time PCR and direct sequence. Out of 520 CHC treatment-naive patients, 42.9% were infected with HCV-1a, 15.4% with HCV-1b, 9.8% with HCV-2, and 31.9% with HCV-3a. Rapid virologic response (RVR), complete early virologic response (cEVR), and sustained virologic response (SVR) were 53.3%, 73.8%, and 66.7%, respectively. Multivariate logistic regression analysis showed that IL28B rs12980275 and IFNL4 ss469415590 in all HCV genotypes were associated with RVR. In addition, IL28B rs12979860 and RVR in all HCV genotypes and IL28B rs12980275, IFNL4 ss469415590, and HLA rs4273729 in HCV subtypes 1a, 1b, and 3a correlated with cEVR. In patient's achieving-SVR, IL28B rs12980275, and RVR in all HCV genotypes and IL28B rs12979860, IFNL4 ss469415590, and HLA rs4273729 in HCV subtypes 1a, 1b, and 3a were the powerful predictor factors. As the first report of its kind published in Iran, we indicated that beside IL28B SNPs and HLA rs4273729, IFNL4 ss469415590 was a powerful predictor factor for RVR, cEVR and SVR. Genotyping these SNPs may be a helpful priority in the treatment of patients with HCV infection, especially in countries where access to triple or double therapy with a viral protease inhibitor is limited.