Independent and Joint Effects of the IL-6 and IL-10 Gene Polymorphisms in Pulmonary Tuberculosis Among the Chinese Han Population

We investigated the association between interleukin (IL)-6 and IL-10 gene polymorphisms and the susceptibility to pulmonary tuberculosis (PTB). DNA samples were obtained from 191 Han Chinese patients with PTB and 191 healthy control subjects. IL-6 (-572, -174, -597) and IL-10 (-1082, -819) polymorphisms were analyzed using polymerase chain reaction-restriction fragment length polymorphism. The IL-6 -572 C/C and IL-10 -819 T/T genotypes were observed less frequently in the case group than in the control group, with crude odds ratios of 0.591 [95% confidence interval (CI) = 0.381-0.917] and 0.401 (95%CI = 0.257-0.627), respectively. A significant association remained after adjusting for environmental factors in multivariate logistic analysis. The homozygote genotypes of IL-6 -572 and IL-10 -819 had an adjusted OR of 0.565 (95%CI = 0.356-0.898) and 0.341 (95%CI = 0.210-0.553), respectively. These results indicate that the mutant heterozygote IL-10 -1082 A/ G+G/G genotype and the homozygote IL-10 -819 T/T genotype have a combined effect on PTB. These results suggest that the IL-6 -572 C/C and IL-10 -819 T/T genotype polymorphisms are protective factors against PTB.