The association of interferon-gamma, interleukin-4 and interleukin-17 single-nucleotide polymorphisms with susceptibility to tuberculosis.

Susceptibility to tuberculosis and progression of the disease depend on interactions between the bacterial agent, host immune system, and environmental and genetic factors. In this case-controlled study, we aimed to determine the role of single-nucleotide polymorphisms of interferon-gamma, interleukin-4 and interleukin-17 in susceptibility to tuberculosis. Genomic DNA was extracted from peripheral blood samples of patients and controls. The association of single-nucleotide polymorphisms in interleukin-4 (-590C/T), interleukin-17 (-152A/G) and interferon-gamma (+874T/A) was investigated by polymerase chain reaction (PCR)-restriction fragment length polymorphism and amplification refractory mutation system-PCR. A total of 76 tuberculosis patients and 119 healthy individuals were included in this study. The interferon-gamma (+874T/A) TA genotype was significantly associated with susceptibility to tuberculosis in patients compared to controls (OR = 1.76; 95%CI = 0.84-3.71; p = 0.007), while the interferon-gamma (+874T/A) TT genotype (OR = 0.51; 95%CI = 0.19-1.36; p = 0.007) had protective effects against tuberculosis and was related to a low risk of tuberculosis development. The difference between allelic and genotypic frequencies of interleukin-4 (-590C/T) between patients and controls was not significant (p = 0.46). Multivariate logistic regression analysis revealed that the interleukin-17 (-152A/G) AG genotype (OR = 2.27; 95%CI = 1.19-4.34; p = 0.03) and AA genotype (OR = 1.03; 95%CI = 0.43-2.44; p = 0.03) were significantly different between patients and controls. In conclusion, single-nucleotide mutations in different cytokine genes may have protective effects or increase the risk of tuberculosis.