role of toll-like receptors in tuberculosis infection

Background: one-third of the world’s population is infected with mycobacterium tuberculosis. investigation of toll-like receptors (tlrs) has revealed new information regarding the immunopathogenesis of this disease. toll-like receptors can recognize various ligands with a lipoprotein structure in the bacilli. toll-like receptor 2 and tlr-4 have been identified in association with tuberculosis infection. objectives: the aim of our study was to investigate the relationship between tlr polymorphism and infection progress. methods: twenty-nine patients with a radiologically, microbiologically, and clinically proven active tuberculosis diagnosis were included in this 25-month study. toll-like receptor 2 and tlr-4 polymorphisms and allele distributions were compared between these 29 patients and 100 healthy control subjects. peripheral blood samples were taken from all patients. genotyping of tlr-2, tlr-4, and macrophage migration inhibitory factor was performed. the extraction step was completed with a qiagen mini blood purification system kit (qiagen, ontario, canada) using a peripheral blood sample. the genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism. results: in total, 19 of the 29 patients with tuberculosis infection had a tlr-2 polymorphism, and 20 of the 100 healthy subjects had a tlr-2 polymorphism (p < 0.001). the tlr-4 polymorphism and interferon-γ allele distributions were not statistically correlated. conclusions: toll-like receptor 2 polymorphism is a risk factor for tuberculosis infection. the limiting factor in this study was the lack of investigation of the interferon-γ and tumor necrosis factor-α levels, which are important in the development of infection. detection of lower levels of these cytokines in bronchoalveolar lavage specimens, especially among patients with tlr-2 defects, will provide new data that may support the results of this study.