Genetic variation in toll-like receptors and retinoic acid-inducible gene I and outcome of hepatitis C virus infection: a candidate gene association study.

We evaluated the effects of genetic variation in toll-like receptors (TLR), retinoic acid-inducible gene I (RIG-I) and their signalling pathways on spontaneous hepatitis C virus (HCV) resolution. We screened 95 single-nucleotide polymorphisms (SNPs) in 22 genes. SNPs significantly associated with resolution in the discovery cohort were genotyped in a validation cohort. Multivariate logistic regression adjusted for sex, hepatitis B surface antigen, HIV infection and the interleukin-28B rs12979860 SNP was performed in the combined cohort. Haplotype reconstruction and linkage disequilibrium analysis were performed. srs2233437, rs730775 and rs28362857 in Inhibitor of NF-kB ε (IkBε) and rs352140 in TLR9 were associated with spontaneous HCV resolution (P ≤ 0.05) in the discovery cohort (n = 308). In the validation cohort (n = 216), we replicated a significant association with HCV resolution for two SNPs in the IkBε, rs2233437 and rs730775. Presence of one or two of the variant allele in rs2233437 had more than twofold higher odds of resolution in adjusted logistic regression (adjusted odds ratio (aOR), 2.6; (95% CI, 1.4, 4.8) P = 0.002). We identified polymorphisms in the IkBε gene associated with spontaneous HCV resolution in two independent cohorts.

Interleukin-28B polymorphisms are associated with hepatitis C virus clearance and viral load in a HIV-1-infected cohort.

Twenty-five per cent of individuals infected with hepatitis C virus (HCV) are able to clear HCV spontaneously. Differences in host genetics are believed to affect the outcome of HCV infection. We analysed an exonic, a promoter and an intronic single nucleotide polymorphism (SNP) of the interferon-λ3 coding interleukin (IL)-28B gene to study the relationship between IL28B SNPs and outcome of HCV infection. Among 206 HIV-1-infected Europeans with evidence of HCV infection, 47 (23%) individuals had cleared HCV and 159 (77%) had developed chronic infection. The exonic rs8103142 CT, the promoter rs12979860 CT and the intronic rs11881222 AG genotypes were associated with a decreased HCV clearance rate with adjusted odds ratios (aOR) of 0.3 (95% CI, 0.1-0.7), 0.4 (95% CI, 0.2-0.8) and 0.4 (95% CI, 0.2-0.8), respectively. The haplotype block TCG CTA was associated with a decreased HCV clearance rate (aOR 0.4, 95% CI, 0.2-0.8). Further, we found significant differences in HCV RNA levels among individuals chronically infected with HCV genotype 1 for rs8103142 and rs12979860 (P ≤ 0.05). Chronically infected individuals with HCV genotype 3 and with the favourable haplotype block CTA CTA had higher median HCV RNA levels than individuals with unfavourable haplotype blocks (P ≤ 0.05). Our findings suggest that IL28B may account for some differences in HCV outcome but that other factors including the viral genotype, host genetics and the host-virus interaction are likely to influence the outcome of HCV infection.