Association of tumor necrosis factor-α-308 (G→A) polymorphism and susceptibility to brucellosis

Background and purpose: A critical response against intracellular organisms such as Brucella spp. is production of tumor necrosis factor-alpha (TNF-alpha), which enhances the initial response of infected macrophages. Polymorphism in the TNF-alpha gene promoter has an effect on the level of TNF-alpha production. Therefore, this study investigated the possible association of G-308A polymorphism of the TNF-alpha. gene and susceptibility to brucellosis. Methods: Genotyping was performed on DNA extracted from the peripheral leukocytes of 260 patients with brucellosis and 217 healthy control participants using the sequence-specific primer polymerase chain reaction method. Results: The TNF-alpha-308(A/A) homozygote was significantly higher in patients than in controls (14.2% vs 5.5%; p = 0.001). Logistic regression analysis showed a significant association between the TNF-alpha-308 (A/A) genotype and brucellosis (odds ratio, 2.4; 95% confidence interval, 1.2-4.8; p = 0.01). Conclusion: The results of this study suggest that TNF-alpha (G-308A) polymorphism might be involved in susceptibility to brucellosis.