Potential Association Between Single Nucleotide Polymorphisms-in the Genes of the Human Toll-like Receptors “TLR2 and TLR9” of Certain Defensive Cells-and the Susceptibility to Pulmonary Tuberculosis in Egyptian Patients

Abstract

SUMMARY Tuberculosis (TB) is a top infectious world killer disease with an estimated 10 million individuals fall ill with TB bacteria every year. The highest worldwide disease prevalence is reported in low- and middle-income countries which are found in Bangladesh, China, India, Indonesia, Nigeria, Pakistan, Philippines and South Africa. Only 5 – 15 % fall ill with active TB, The rest have TB infection but are not diseased and don’t transmit the infection. Every year 1.5 million individual die from TB. TB leads to death of people with HIV and contributor to antimicrobial resistance. Toll-like receptors (TLRs) are “pattern recognition receptors” (PRRs) expressed on macrophages and leukocytes. TLRs are critical to innate immune responses and tuberculosis adapts TLR function to evade immune clearance. In this cross sectional study, convenience sample of 238 unrelated individuals were obtained. They were divided into 140 patient subjects with diagnosis of pulmonary tuberculosis and 98 household healthy subjects as controls. All subjects were genotyped for TLR9.rs5743836 and TLR2.rs5743708 SNPs by PCR-RFLP analysis while TLR9.rs352139 SNPs by ARMS-PCR (amplification refractory mutation system-PCR). The data revealed that the “GG” genotype and “G” allele in TLR2 Arg753Gln are the most frequent genotype/allele in both groups; while the “AA” genotype and “A” allele are the least frequent ones. A total loss of “AA” genotype occurred in the control group. The present study did not find any significant association between TLR2 Arg753Gln polymorphism and the risk of tuberculosis.