Variations in KIR Genes: A Study in HIV-1 Serodiscordant Couples

Background. NK cells have anti-HIV activity mediated through killer cell immunoglobulin-like receptors (KIRs). The current prospective cohort study evaluated whether variation in KIR genes is associated with HIV infection in discordant couples (DCs), where one spouse remains seronegative (HSN) despite repeated exposure to the HIV. Methods. KIR was genotyped using PCR SSP. Viral load and CD4 counts were estimated using commercially available reagents. Data were analyzed using SPSS software. Results. Among the 47 DCs, HSN spouses had significantly (P = 0.006) higher frequencies of KIR3DS1. Regression analysis revealed significant (P = 0.009) association of KIR2DS1 with low viral load. KIR2DS4 variant was associated (P = 0.032) with high viral load. Three pairs of KIR genes were in strong LD in HSNs and two pairs in HSPs. There were 60 KIR genotypes, and 16 are reported the first time in the Indian population. Exclusive genotypes were present either in HSPs (N = 22, 11 unique genotypes) or in HSNs (n = 27, 9 unique genotypes). Conclusions. This study highlights for the first time in the Indian population an association of KIR genes in HIV infection where presence of exclusive and unique genotypes indicates possible association with either HIV infection or with protection.