The correlation between TLR9 (rs148805533 Del/Ins) gene polymorphisms and susceptibility to pulmonary tuberculosis

Background: One of the main infectious causes of morbidity and mortality worldwide is Mycobacterium tuberculosis. The Toll-like receptor (TLR) genes’ polymorphisms and mutations have been linked to an increased risk of infection in general. Objectives: This study aimed to investigate the association among TLR9 (rs148805533 Del/Ins), gene polymorphism, and pulmonary tuberculosis (PTB). Materials and Methods: Blood and sputum samples were collected from 70 patients with PTB and 30 healthy as a control group. Patients were diagnosed clinically by the specialized physician, in addition to use the acid-fast smear and culture on Lowenstein–Jensen. In addition, the molecular diagnostics technique was used by Gene Xpert device. The genotyping was carried out by using allele specific-polymerase chain reaction technique, and the TLR9 concentration was estimated by enzyme-linked immunosorbent assay (ELISA) technique. Results: The results of TLR9 polymorphism showed that the Ins/Ins allele, Del/Ins allele, and Del/Del allele genotypes frequencies at the site of (rs148805533) polymorphisms were significantly higher in PTB patients than the control groups (P = 0.05). The Ins/Ins allele genotype was the most frequent in PTB patients. In addition, the insertion allele was the most frequent in PTB patients and control groups. Conclusion: Our results indicated that in a sample of the local Iraqi population, the TLR9 (rs148805533) gene polymorphism may be a significant genetic determinant for PTB susceptibility.