Detection of molecular epidemiological characteristics of Helicobacter pylori strains isolated from Çukurova region

Background and aims: Helicobacter pylori (H.pylori) is a gastric pathogen that chronically infects more than half of the world?s population and the major cause of neoplastic and inflammatory gastroduodenal diseases of the stomach. It has been proposed that the complex interactions between the bacterial and host genetic factors, along with environmental factors, play a significant role in determining the differential clinical outcome among various individuals. Many bacterial virulence genes, including the pathogenicity island cagA, the s1m1 vacA alleles, babA2, sabA and oipA, have been associated with a higher degree of gastric mucosal inflammation. The immune system also plays an important role in the pathogenesis of gastroduodenal diseases by regulating intensity of the inflammatory response to H.pylori infection. Some biallelic polymorphisms have been reported in IL1B, all representing Cytosine/Timine base transition at positions 511 and 31 from the transcriptional initiation site and IL-RN*2 polymorphisms which are related with gastric inflamation degree. However, the results of epidemiological studies on the association of IL1B polymorphisms with duodenal ulcer, gastritis and gastric cancer in different populations are conflicting. The current study evaluated the role of cytokine gene (IL-1B, IL-1RN) polymorphisms and bacterial virulance markers on develolepment gastrointesinal diseases during H.pylori infection in the Cukurova region.Materials and Methods: In 210 patients with gastric symptom and 90 healty control group, polymorphisms at different loci of the IL-1B, and IL-1 receptor antagonist (IL-1RN), were genotyped by PCR, restriction fragment length polymorphism (RFLP) analysis. Presence of H.pylori and bacterial virulence factors was investigated by glmM, cagA, vacAs1/2, and vacAm1/2 PCR from gastric tissue samples.Results: In the result of glmM-PCR analysis, the presence of H.pylori DNA was detected in 89 (80,9 %) of the 110 symptomatic patients. Of colonized strains 64 % were cagA+vacA+ Type-I strains and the most vacA allelic combination seen in Type-I and Type-II strains was s1/m2 with 25 (28 %) strains and s1/m1 with 23 (25,8 %) strains. Heterozygous IL-1RN 1/2 and IL-1B C/T genotypes were more frequent than in gastritis patients. The carriage of IL-1RN*2 independently increased the risk of gastritis, with odds ratio of 1,81 [95 % confidence interval (CI), 1,094?3,0], p=0,02 and the carriage of IL-1 RN L allel reduced the risk gastritis with odds ratio of 0,168 [95 % confidence interval (CI), 0,039-0,725], p= 0,007. IL-1B (-511 and -31 C/T) genotype/allele were not associated with gastroduodenal pathology.Conclution: Cytokine gene polymorphisms influence gastric inflammation in H.pylori infection. An interplay between bacterial virulence factors and cytokines genotypes, is probably the main route causing H.pylori infection to lead to different gastric diseases. A combination of bacterial testing and host genotyping may target the eradication of H.pylori to high-risk individuals.Keywords: H.pylori, glmM, cagA, vacA, vacA alleles, IL-1ß polymorphism.