gms | German Medical Science

HLA-restricted Cytotoxic T-lymphocytes that are capable of suppressing HIV replication exert a strong pressure on the virus favoring the selection of escape mutations. Protective HLA molecules drive the selection of escape mutants that reduce viral replicative capacity. Transmission of viruses with low viral replicative capacity result in lowering of early viral set-point and a higher CD4 count in the recipients.

Here we investigated two comparable maternal cohorts of HIV-infected, antiretroviral-therapy-naïve women recruited from the same site in Umlazi, Durban, in 2002-5 (n=328) and in 2012-13 (n=250), respectively. We hypothesized that the total number of HLA-associated polymorphisms at a population-level adaptation of HIV is contributing to the reduction in viral set-point observed over a 10-year period in Umlazi, Durban, a site at the epicenter of the global HIV epidemic. Preliminary results demonstrate significantly lower viral loads, increased CD4 counts and increased number of HLA-associated polymorphisms in the 2012-13 cohort compared with the 2002-5 cohort (p<0.001). Moreover we found a significant decrease in viral load and increase in CD4 count when correlated with total number of HLA-associated polymorphisms per Gag sequence across the two cohorts (p<0.001).

Although these data are preliminary and the sequencing data from the entire cohort of 250 are pending, they suggest that the lower viral loads observed in the 2012-13 cohort is strongly correlated with the accumulation of HLA-associated polymorphisms at a population level, with consequent reductions in viral replicative capacity and improved immune control. Further analyses are required to evaluate the impact of HIV adaptation to protective HLA molecules such as HLA-B*57 on changing virulence in the HIV epidemic over a 10-year period.