Study of TNF-α, IFN-γ, TGF-β, IL-6, and IL-10 Gene Polymorphism in Individuals from the Leprosy-Endemic Area in the Brazilian Amazon

This study aimed at verifying the relationship between the polymorphisms of the cytokines tumor necrosis factor-alpha (TNF-alpha) -308 G -> A (rs1800629); interferon gamma (IFN-gamma) +874 T -> A (rs2430561); transforming growth factor-beta (TGF-beta) codon 10 (rs1982073) and codon 25 (rs1800471); interleukin (IL)-6 - 174 G -> C (rs180079) and IL-10 - 1082 A -> T (rs1800896); -819 C -> T (rs1800871); -592 A -> C (rs1800872); and leprosy. Blood samples were analyzed from 106 individuals, of whom 24 were paucibacillary (PB), 28 were multibacillary (MB), and 54 were patient contacts. Analysis of cytokine polymorphisms was typified by the polymerase chain reaction technique. For TGF-beta +869 T -> C and +915 G -> C, a tendency to associate the presence of the C allele at codon 10 with leprosy was demonstrated, with the T allele being most frequently found in the CCOSI (P = 0.056). For the polymorphisms IL-10 - 1082 A -> T, -819 C -> T, and -592 A -> C, we found an association of the GCC/GCC genotype with the susceptibility to the disease and the A allele at position 1082 with the leprosy protection. Greater predominance was found of ACC/ATA (31.3%) and GCC/ATA (37.5%) (P = 0.03) and the A allele at position -1082 (76.85%) (P = 0.043) in the CCOSI groups, whereas the GCC/GCC was found in the MB group (22.2%) (P = 0.05). For the other cytokines's single-nucleotide polymorphisms, there were no associations with susceptibility to leprosy. These results are limited by sample size, may not be conclusive, and will need further confirmation in a larger cohort.