Can IFNL3 polymorphisms predict response to interferon/ribavirin treatment in hepatitis C patients with genotype 3?

Favourable genotypes of IFNL3 polymorphism CC for rs12979860 and TT for rs8099917 are strongly associated with the interferon/ribavirin treatment outcome in hepatitis C virus (HCV) patients with genotypes 1 and 4. Contrarily, conflicting results have been reported for patients with HCV genotypes 2 and 3. Therefore, we sought to investigate the association between IFNL3 with sustained virological response (SVR) after treatment to ascertain the predictive value of IFNL3 single-nucleotide polymorphisms (SNPs) in HCV patients with genotype 3. For this purpose, we genotyped five IFNL3 SNPs, rs12980275, rs12979860, rs9109886, rs8099917 and rs7248668, in HCV patients with genotype 3 and assessed its association with SVR, individually and in haplotype. Interestingly, we report that the IFNL3 SNPs we genotyped have shown no association with SVR following treatment, either individually or in haplotype, indicating that genotyping IFNL3 SNPs have limited predictive value in HCV patients with genotype 3. Therefore, we propose that IFNL3 genotyping can be excluded from a patient's pre-treatment workup for subsequent treatment choice. This will greatly reduce the economic burden for HCV patients with genotype 3 in resource-limited regions, especially South Asia where genotype 3 is predominant.