Tumor Necrosis Factor-alpha -308G/A Polymorphism Associated with Increased Risk for Pulmonary Tuberculosis in Medan City, Indonesia

BACKGROUND: Tumor Necrosis Factor-alpha (TNF-α) is a pro-inflammatory cytokine that plays a role in immune response against tuberculosis (TB) infection. Polymorphism in TNF-α gene may be associated with susceptibility to pulmonary TB (PTB). AIM: The purpose of this study was to investigate whether TNF-α-308G/A gene polymorphism is associated with susceptibility to PTB in Medan city, Indonesia. METHODS: This is a case–control study with 100 PTB patients and 100 healthy control. TNF-α polymorphism genotyping was performed by polymerase chain reaction fragment length polymorphism method. RESULTS: There were 200 participants enrolled in this study. Most of the participants were male and were in the age range of 20–39 years. Genotyping examination revealed that in the TB group, AG and GG genotype was found in 80 people (80%) and 20 people (20%), respectively. There were no TB patients with AA genotypes. Whereas, in the control group, subjects with AA, AG, and GG genotypes were 2 (2%), 47 (47%), and 51 (51%), respectively. Statistical analysis showed that there was a significant relationship between TNF-α-308 G/A polymorphism and PTB, in which individuals with AG genotypes were 4.3 times more likely to suffer PTB compared to GG genotype (p < 0.001, 95% confidence interval (CI) 2.31–8.15). Further analysis showed that A allele increased the risk of TB incidence by 1.94-fold compared to the G allele (p = 0.002, 95% CI 1.27–2.98). CONCLUSIONS: There was a significant relationship between TNFα-308 G/A gene polymorphism and the susceptibility to PTB and A allele increases the risk of pulmonary TB compared to G allele.