Toll-like Receptor 1 743 A>G, 1805 T>G & Toll-like Receptor 6 745 C>T gene polymorphism and tuberculosis: A case control study of north Indian population from Agra (India)

Infection with Mycobacteriumtuberculosis possibly depends on host genetic factors and is thought to be the major cause of differential susceptibility to the disease. In the present study, 205 pulmonary tuberculosis cases and 127 healthy controls were studied for the association of Toll-like Receptor (TLR) variants (TLR1 variants 743A>G and 1805T>G, and TLR6 variant 745 C>T) in north Indian population. The frequency of heterozygous genotypes (AG) in TB cases (0.47) and HCs (0.61), differed significantly (p value = 0.02). The association of AG genotypes in HCs was adjusted for gender as gender was observed to be a confounder and M−H OR was found to be 0.62 (p = 0.044). On categorizing the cases basing on AFB smear positivity, the heterozygous genotypes (AG) was found to be associated with low bacillary load (scanty and 1+) (P = 0.002). No association was observed for either TLR1 1805 T>G or TLR6 745 C>T polymorphism. Level of serum IL6 was found to be significantly higher among healthy controls with TLR1 GG genotype compared to healthy controls with AA (p = 0.035) and AG (p = 0.005) genotypes. Thus, it may be suggested that the heterozygous condition for TLR1 743 A>G provide resistance from the disease. However, in depth study is required to understand the mechanism for possible protective responses.