Association of IFNλ4 rs12979860 polymorphism with the acquisition of HCV and HIV infections among people who inject drugs.

We investigated the presence of a single-nucleotide polymorphism designated rs12979860 in the interferon λ4 (IFNλ4) gene among 345 people who inject drugs (PWID) and 495 blood donors to evaluate associations between the rs12979860 genotypes and human immunodeficiency virus/hepatitis C virus (HIV/HCV). The rs12979860 TT genotype was over-represented among HIV+ PWID than HIV- PWID and blood donors (16% vs 8% and 10%, P = 0.03, respectively). PWID with TT genotype had approximately twice the probability of being HIV+ (odds ratio [OR], 2.19; 95% confidence interval [CI], 1.11 to 4.33) than PWID without TT. Every additional year of intravenous drug use (IVDU) decreased the OR 1.16 times (OR, 0.86; 95% CI, 0.75 to 0.98). This suggests that rs12979860 TT increases susceptibility to HIV and this impact decreases with increasing duration of IVDU.