Single-nucleotide polymorphisms (SNPs) in Toll-like receptor (TLR) genes TLR2-4 and TLR7-9, but not in TLR1 and TLR6, have been previously evaluated regarding human immunodeficiency virus (HIV) acquisition and disease progression in various populations, most of which were European.
Increased expression of TLR2 was found on monocytes in HCV-infected patients with fibrosis (p < 0.01), co-infected with HIV (p = 0.03), and possibly in patients without fibrosis (p = 0.07) when compared to controls.
Another PPE protein, Rv1196 (PPE18), was also found to interact with TLR2 but had no effect on HIV-1 LTR trans-activation because of its inability to activate the NF-κB signaling pathway.