title: Role of Toll-Like Receptors in Tuberculosis Infection.
abstract: BACKGROUND
  One-third of the world's population is infected withMycobacterium 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.
  
  
  OBJECTIVE
  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.
authors.affiliation: Clinic of Chest Diseases, Kusadasi Universal Hospital, Aydin, Turkey.
authors.forename: Oguz Oben
authors.initials: OO
authors.lastname: Biyikli
authors.affiliation: Chest Diseases Department, School of Medicine, Izmir University, Izmir, Turkey.
authors.forename: Aysegul
authors.initials: A
authors.lastname: Baysak
authors.affiliation: Medical Microbiology Department, School of Medicine, Izmir University, Izmir, Turkey.
authors.forename: Gulfem
authors.initials: G
authors.lastname: Ece
authors.affiliation: Chest Diseases Department, School of Medicine, Izmir University, Izmir, Turkey.
authors.forename: Adnan Tolga
authors.initials: AT
authors.lastname: Oz
authors.affiliation: Chest Diseases Department, School of Medicine, Ege University, Izmir, Turkey.
authors.forename: Mustafa Hikmet
authors.initials: MH
authors.lastname: Ozhan
authors.affiliation: Pediatrics Department, School of Medicine, Ege University, Izmir, Turkey.
authors.forename: Afig
authors.initials: A
authors.lastname: Berdeli
keywords: Genetic Polymorphism; Infection; Mycobacterium tuberculosis; Toll-Like Receptor