Association study of single nucleotide polymorphism of human Toll like receptor 9 and susceptibility to pulmonary tuberculosis in Egyptian population

Abstract

Toll-like receptors (TLRs) are known to play important roles in human innate immune systems. Polymorphisms in and functions of TLRs have been investigated to identify associations with specific infectious diseases including tuberculosis (TB). This study was performed for 166 samples of unrelated individual's diagnosis of pulmonary tuberculosis and 98 household healthy samples. Genomic DNA was extracted from EDTA-anticoagulated peripheral blood. The alleles of (rs352140) TLR9 gene polymorphisms were detected using polymerase chain reaction restriction fragment length polymorphism. The resulting fragments were separated in 3% agarose gel electrophoresis. The sequence results generated by the forward and reverse sequencing primers were analyzed with the software program sequencing analysis. Sequence comparisons of three genotypes AG, AA, and GG were performed using the multiple-alignment algorithm in Megalign. The direct counting was used to determine the allele and genotype frequencies of each polymorphism. Hardy-Weinberg equilibrium (HWE) tests were performed in controls by Fisher exact test. Significant deviations from the HardyWeinberg equilibrium in the distribution of the TLRs SNP genotypes in TB patients and controls were not detected for the SNP TLR9rs352140 for both patients and controls. These results do not indicate a major influence of these putative functional TLR SNP on the susceptibility to (or protection from) tuberculosis in Egyptian population.