Endosomal toll-like receptor gene polymorphisms and susceptibility to HIV and HCV co-infection - Differential influence in individuals with distinct ethnic background

The genetic background of human populations can influence the susceptibility and outcome of infection diseases. Toll-like receptors (TLRs) have been previously associated with susceptibility to human immunodeficiency virus (HIV) infection, disease progression and hepatitis C, virus (HCV) co-infection in different populations, although mostly in Europeans. In this study, we investigated the genetic role of endosomal TLRs on susceptibility to HIV infection and HCV co-infection through the analysis of TLR7 rs179008, TLR8 rs3764880, TLR9 rs5743836 and TLR9 rs352140 polymorphisms in 789 Brazilian individuals (374 HIV+ and 415 HIV−), taking into account their ethnic background. Amongst the 357 HIV+ individuals with available data concerning HCV infection, 98 were positive. In European descendants, the TLR9 rs5743836 C carriers displayed a higher susceptibility to HIV infection [dominant, Odds Ratio (OR) = 1.53; 95% CI: 1.05-2.23; P = 0.027]. In African descendants, TLR9 rs5743836 CT genotype was associated with protection to HIV infection (codominant, OR = 0.51; 95% CI: 0.30-0.87; P = 0.013). Also, the TLR9 rs352140 AA variant genotype was associated with susceptibility to HIV+/HCV+ co-infection in African descendants (recessive, OR = 2.92; 95% CI: 1.22-6.98, P = 0.016). These results are discussed in the context of the different ethnic background of the studied individuals highlighting the influence of this genetic/ethnic background on the susceptibility to HIV infection and HIV/HCV co-infection in Brazilian individuals.