TLR9 2848 G/A Gene Polymorphism in HCV+, HIV+, and HCV+/HIV+ Individuals

Host genetic factors play a major role with respect to susceptibility to infections. Many polymorphisms of the Toll-like receptors (TLRs), members of the innate immune response, are directly associated with the clinical outcomes following infection. The 2848 G/A variant (rs352140) of the TLR9 gene is associated with increased TLR9 expression. However, the impact of the genotypes of this SNP on HIV+, HCV+, and HCV+/HIV+ individuals is still debated. This study investigated the 2848 G/A polymorphism in HCV infection, HIV infection, and HCV/HIV co-infection in a large sample of Brazilians (n = 1,182). Groups were initially compared without considering stratification by ethnicity and subsequently stratifying individuals between whites and non-whites. Considering non-white individuals, a significant difference between the HIV+/HCV+ group and controls was observed with the GG genotype serving as a protective factor (p = 0.023). Additionally, significant allelic differences were observed between the HCV+ group and controls (p = 0.042); between the HIV+/HCV+ group and controls (p = 0.011); and between the HIV+/HCV+ group and HIV+ individuals (p = 0.047). However, all significant results were lost following adjustment for multiple comparisons (p > 0.05). Although our initial results indicated a potential influence of the rs352140 genotype on host altered susceptibility to viral infections, following correction for multiple comparisions the standard (p < 0.05) for statistical association was lost. This may be due to insufficient sample size as we were examining many different associations. Thus, a larger study is warranted to further pursue this topic.