Interleukin-10 and tumor necrosis factor-α gene polymorphisms in tuberculosis

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is an infectious disease in humans killing nearly three million people and eight million cases annually. The cytokines TNF-alpha and IL-10 have been implicated in the pathogenesis of TB. Certain single nucleotide polymorphisms within the promoter region of the IL10 and TNF genes have been associated with altered levels of circulating IL10 and TNF-alpha. We analyzed TNF-a (-308 G/A, -238 G/A, -376 G/A) and IL10 (-1,082 G/A, -819 C/T, -592 C/A) polymorphisms in 128 patients with TB and 80 healthy subjects using by amplification refractory mutation system-polymerase chain reaction (ARMS-PCR). A significant association was found between TB and -1,082 G allele (Pc: 0.000, OR 2.22, 95% CI 1.45-3.4 1). Significant difference was observed in IL10 GCC and ACC haplotypes distribution between TB and control subjects (Pc: 0.000, OR 2.22, 95% CI 1.45-3.41; Pc: 0.004, OR 0.53, 95% CI 0.35-0.81). No statistically significant association was found between IL-10 -819 C/T, TNF-alpha 308 G/A, -238 G/A, -376 G/A polymorphisms, functional TNF alpha/IL-10 genotypes and TB. Our findings suggest that IL-10 108 2G/A alleles or haplotypes containing these alleles may influence the Th1/Th2 balance and hence may play a role in TB susceptibility and increase risk of developing disease. This polymorphism may be one of the many genetic factors affecting disease outcome.