Genetic Polymorphisms of IL1B, IL6, and TNF α in a Chinese Han Population with Pulmonary Tuberculosis

Abstract

Background. The factors that predispose to pulmonary tuberculosis (PTB) are not fully understood. Previous studies have shown that cytokine gene polymorphisms were associated with PTB. Objectives. In this study, we have investigated the relationship between ILB, IL6, and TNFα polymorphisms and a predisposition to Mycobacterium tuberculosis (MTB) infection and PTB. Methods. A total of 209 cases of PTB, 201 subjects with latent TB infection (LTBI), and 204 healthy controls (HCS) were included in this study. Logistic regression analyses under allelic, homozygous, and heterozygous models were used to calculate P values, odds ratios (ORs), and 95% confidence intervals (CIs) for assessing the association between single nucleotide polymorphisms (SNPs) and disease risk, adjusting for sex and age. Genotyping was conducted using the improved multiplex ligase detection reaction (iMLDR) method. Results. When comparing PTB patients with LTBI subjects, significant associations with disease development were observed for SNPs of IL6 and TNFα. When comparing LTBI subjects with HCS, IL1B polymorphisms were significantly associated with LIBI. Haplotype analyses suggested that the CGG haplotype of IL1B was associated with an increased risk of PTB (P=0.039, OR = 1.34, 95% CI: 1.01-1.76), while the TTGCG haplotype of TNFα was a protective factor against PTB (P=0.039, OR = 0.66, 95% CI: 0.44-0.98). Conclusion. Our study demonstrated that IL1B variants were related to LTBI and IL6 and TNFα variants were associated with PTB.