Single Nucleotide Polymorphisms in IL17A and IL6 Are Associated with Decreased Risk for Pulmonary Tuberculosis in Southern Brazilian Population

PLoS One. 2016 Feb 3;11(2):e0147814. doi: 10.1371/journal.pone.0147814. eCollection 2016.

Abstract

In Mycobacterium tuberculosis (MTB) infection, the complex interaction of host immune system and the mycobacteria is associated with levels of cytokines production that play a major role in determining the outcome of the disease. Several single-nucleotide polymorphisms (SNPs) in cytokine genes have been associated with tuberculosis (TB) outcome. The aim of this study was to evaluate the association between previously reported SNPs IL2-330 T>G (rs2069762); IL4-590 C>T (rs2243250); IL6-174 G>C (rs1800795); IL10-592 A>C (rs1800872); IL10-1082 G>A (rs1800896); IL17A -692 C>T (rs8193036); IL17A -197 G>A (rs2275913); TNF -238 G>A (rs361525); TNF -308 G>A (rs1800629) and IFNG +874 T>A (rs2430561) and pulmonary TB (PTB) susceptibility. We conducted a case-control study in individuals from Southern Brazil who were recruited between February 2012 and October 2013 in a high incidence TB city. We performed a multiplex genotyping assay in 191 patients with PTB and 175 healthy subjects. Our results suggest a decreased risk for PTB development associated with the IL17A -197A allele (OR = 0.29; p = 0.04), AA genotype (OR = 0.12; p = 0.04) and A carrier (AG/AA) (OR = 0.29; p = 0.004) and IL6 -174C carrier (CC/CG) (OR = 0.46; p = 0.04). We could not properly analyze IL17A -692 C>T (rs8193036) and IFNG +874T>A due to genotypic inconsistencies and found no evidence of association for the IL2, IL4, IL10 and TNF polymorphisms and PTB. In conclusion, our results show a protective effect of IL17 and IL6 polymorphisms on PTB outcome in Southern Brazilian population.

MeSH terms

  • Adult
  • Brazil / epidemiology
  • Case-Control Studies
  • Female
  • Gene Frequency / genetics
  • Genetic Predisposition to Disease
  • Humans
  • Interleukin-17 / genetics*
  • Interleukin-17 / immunology
  • Interleukin-6 / genetics*
  • Interleukin-6 / immunology
  • Male
  • Mycobacterium tuberculosis / immunology*
  • Polymorphism, Single Nucleotide
  • Risk
  • Tuberculosis, Pulmonary / epidemiology*
  • Tuberculosis, Pulmonary / immunology*
  • Tuberculosis, Pulmonary / microbiology

Substances

  • IL17A protein, human
  • IL6 protein, human
  • Interleukin-17
  • Interleukin-6

Grants and funding

The authors have no support or funding to report.