Incidence and association of genetic variations of IL-19 gene with H. pylori infection in the South Iranian population

Abstract

Interleukin-19 (IL-19) is a pleiotropic cytokine with pro- as well as anti-inflammatory properties. It plays an important role in the pathogenesis of Helicobacter pylori (H. pylori) infection which in turn has been shown to be a major etiological factor in the development of gastric cancer and ulcers. Single Nucleotide Polymorphisms (SNPs) which alter the functioning of IL-19 could thus play a pivotal role in the pathogenesis as well as the outcome of these diseases. In this study, we explored the association of rs2243191 (Ser175Phe) and rs1028181 (−513 T/C) polymorphisms in IL-19 with the incidence of H. pylori infection in an Iranian population. 130 patients diagnosed with H. pylori infection (anti-H. pylori IgG titers > 90 ng/ml) and 130 healthy volunteers were genotyped for these two polymorphisms using Amplification-Refractory Mutation System (ARMS) PCR and Restriction Fragment Length Polymorphism (RFLP) PCR respectively. We analyzed the allelic frequencies of rs1028181 and rs2243191 polymorphisms in patients infected with H. pylori. The IL-19 gene polymorphism at rs1028181 was found to be significantly associated with the incidence of H. pylori infection (C vs. T, OR = 0.68; CI = 0.46 (1–0.01, P = 0.03)) suggesting a dominant role of rs1028181 mutation. However, no significant correlation between rs2243191 and H. pylori infection (C vs. T, OR = 0.65, CI = 0.35–(1-0.28, P = 0.22)) was observed. Furthermore, the serum levels of anti-H. pylori IgG were found elevated in the dominant allele. All these findings suggest a role of IL-19 in the pathogenesis of H. pylori infection, however, it may require further replication and validation.