The IL-17 G-152A single nucleotide polymorphism is associated with pulmonary tuberculosis in northern Spain.

Background: Interleukin 17 (IL-17) is induced during the early stages of tuberculosis infection, playing an important role in the defense against mycobacterial infection. To date, only one study performed in Chinese Han population has found an association between IL-17F sequence variants and susceptibility to tuberculosis, but no relationship has been found with another single nucleotide polymorphism (SNP) in IL-17A gene (rs2275913).

Methods: To assess if rs2275913 (G-152A) SNP, could be associated with susceptibility to pulmonary tuberculosis (PTB) in a genetically homogeneous Caucasian population, we analyzed if its allele and genotype frequencies were statistically significant in a case-control study. One hundred and ninety-two patients with active PTB and 266 blood healthy donors were enrolled in this study.

Results: The frequency of the GG versus GA+AA genotype was significantly more frequent in patients with PTB than in control subjects assuming a dominant model (50.52% versus 39.10% respectively, OR=1.59, 95%CI=1.09-2.31, p=0.015). Despite patients with PTB had higher serum IL-17 levels, we did not find an association of this SNP with IL-17 ex vivo production after stimulation with Mycobacterium tuberculosis (Mtb) antigens or phytohemagglutinin (PHA).

Conclusion: Our results would suggest an association between IL-17A rs2275913 - 152G allele and GG genotype with susceptibility to PTB for the first time.