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Open Access Highly Accessed Research article

Potential association of pulmonary tuberculosis with genetic polymorphisms of toll-like receptor 9 and interferon-gamma in a Chinese population

Yu Yang1, Xiangwei Li1, Wei Cui2, Ling Guan2, Fei Shen2, Jinsheng Xu2, Feng Zhou1, Mufei Li1, Cong Gao1, Qi Jin1, Jianmin Liu2* and Lei Gao1*

Author Affiliations

1 MOH Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China

2 Henan Provincial Hospital of Infectious diseases, Zhengzhou, China

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BMC Infectious Diseases 2013, 13:511  doi:10.1186/1471-2334-13-511

Published: 31 October 2013

Abstract

Background

Association studies have been employed to investigate the relationships between host single nucleotide polymorphisms (SNPs) and susceptibility to pulmonary Tuberculosis (PTB). However, such candidate genetic markers have not been widely studied in Chinese population, especially with respect to the disease development from latent M. tuberculosis infection (LTBI).

Methods

In this case–control study, 44 candidate SNPs were examined in a total of 600 participants (PTB patients, LTBI controls and healthy controls without M. tuberculosis infection) from Zhengzhou, China. The two groups of controls were frequency matched on gender and age with PTB patients. Genotyping was carried out by the Illumina Golden Gate assay.

Results

When comparing PTB patients with LTBI controls but not healthy controls without M. tuberculosis infection, significant associations with disease development were observed for TLR9 1174 A/G, TLR9 1635 A/G and IFNG 2109G/A. The two loci in TLR9 were in LD in our study population (r2=0.96, D’=1.00). A combined effect of the genotypes associated with increased risk of PTB (i.e. TLR9 1174G/G and IFNG 2109 A/A) was found when comparing PTB patients with LTBI controls (p=0.004) but not with healthy controls without infection (p=0.433).

Conclusions

Potential associations between TLR9 and IFN-γ genetic polymorphisms and PTB were observed in a Chinese population which supports further study of the roles played by TLR9/IFN-γ pathway during the development of PTB.

Keywords:
Pulmonary tuberculosis; TLR9; IFN-γ; Genetic polymorphisms; Susceptibility; Chinese