Association between KIR genotypes and HLA-B alleles on viral load in Southern Brazilian individuals infected by HIV-1 subtypes B and C.

There is a great variety of HIV-1 subtypes circulating in Brazil, including subtype C, whose prevalence is on the rise, particularly in the southern region. Many host and viral genetic factors may be involved in this trend. We evaluated the influence of human leukocyte antigen (HLA) class I alleles and killer-cell immunoglobulin-like receptor (KIR) genotypes on viral set point and T-CD4+ parameters in 84 treatment-naïve HIV-1-positive individuals. Frequency data in the infected group were compared to data of 548 healthy control subjects. Individuals with the KIR AA genotype had a higher viral load (VL) than individuals with the KIR Bx genotype. The HIV-1 group was subdivided into three subgroups according to HLA-B allele presence: those with protection to disease alleles (HLA-B+), accelerated disease progression alleles (HLA-B−), or neither (HLA-Bo) were grouped. We observed a significant effect of the HLA-B allele presence on VL. The HLA-B+ group had significantly lower VL than the HLA-B− group and trended toward a lower VL than the HLA-Bo group. There were significant differences between groups expressing extreme VL values: KIR-AA+HLA-B− vs. KIR Bx+HLA-B+ and KIR-AA+HLA-Bo vs. KIR Bx+HLA-B+. The relationship of KIR/HLA host genetics with slow HIV disease progression in southern Brazil may be useful for vaccine developers, epidemiologists, and clinicians.