Association of polymorphisms in the TNFA, TNFRSF1A and TNFRSF1B genes with lepromatous leprosy in Western Mexican patients

Introduction: Studies in different populations have shown that single-nucleotide polymorphisms (SNPs) of tumor necrosis factor-alpha (TNFα) and TNF receptors 1 and 2 (TNFR1 and TNFR2) may be involved in the pathogenesis of lepromatous leprosy (LL). To further explore the results in a Mexican population, we compared the frequencies of the polymorphisms in - 308 G>A TNFA (rs1800629), - 383 A>C TNFRS1A (rs2234649), and + 196 T >G TNFSR1B (rs1061622) genes in LL patients (n = 133) and healthy subjects (n = 198).

Methodology: The genotyping was performed with the polymerase chain reaction-based restriction fragment length polymorphism (PCR–RFLP) technique. Statistical analysis was performed using the χ2 test, within the 95% confidence interval. Odds ratios (OR) were calculated and Hardy-Weinberg equilibrium was verified for all control subjects and patients.

Results: We found an association between the TNFSR1 -383 A>C genotype and the risk of lepromatous leprosy when leprosy patients were compared to controls (OR = 1.71, CI: 1.08-2.69, p = 0.02). Furthermore, it was also associated with the risk of LL in a dominant model (AC + CC vs AA, OR: 1.65, 95% CI: 1.05-2.057, p = 0.02). Similar genotype and allele frequencies for the SNPs TNFA - 308 G>A and TNFSR2 + 196 T>G were observed between leprosy patients and healthy subjects.

Conclusions: The TNFSR1 -383 A>C could be a potential marker for the identification of high-risk populations. However, additional studies, using larger samples of different ethnic populations, are required.