Association of Interleukin-17 A Gene Variants and Susceptibility to H. Pylori Related Gastric Diseases

Background: Helicobacter (H) pylori is the main cause of chronic active gastritis (CAG), leading to peptic ulcer (PU), gastric adenocarcinoma, and gastric mucosa associated lymphoma. Objective: As interleukin (IL)-17 has a critical role in inflammation and its function is influenced by some variations in this gene, we aimed to investigate the association between single nucleotide polymorphisms (SNPs) of IL-17A and the risk of H. pylori induced CAG and PU. Methods: The study was carried out on 100 patients with CAG and 50 patients with PU infected with H. pylori as cases, and 226 healthy individuals as controls. We genotyped nine SNPs in IL-17A gene using PCR-RFLP technique and the distribution of alleles and genotypes frequencies were compared among the case and control groups. Results: The frequency of rs3819024 A allele was significantly higher in the CAG patients (P = 0.0003) and PU patients (P = 0.0001). Moreover, rs3819024 GG genotype was significantly higher in controls compared with CAG (P = 0.0008) and PU (P = 0.0005) patients. Analysis of haplotype reconstructed from rs4711998 A and rs3819024 A revealed that the AA haplotype was more frequent in PU patients compared with the controls (P = 0.0002) and conversely GG haplotype was significantly higher in controls than in PU patients (P = 0.001). Conclusion: Our results indicate that the presence of some allele, genotype and haplotype of IL-17A could possibly increase the risk of gastritis induced by H. pylori in Iranian population.