Relationship between Helicobacter pylori hopQ genotype and clinical outcome in Asian and Western populations

Abstract

Outer membrane proteins of Helicobacter pylori mediate important pathogen-host interactions such as colonization, adhesion and the inflammatory response. hopQ genotypes have been suggested to be associated with increased risk of peptic ulcer. The aim of this study was to test the relation of hopQ genotype to H. pylori-related disease and histological changes in Asian and Western countries. hopQ genotype, cagA status and vacA genotype of H. pylori isolated from patients from Asian and Western countries were determined and the results were compared with the clinical presentation and gastric histology. Most Asian strains possessed virulent genotypes (hopQ type I, vacA s1-m1 and cagA-positive). In Western countries, hopQ type I genotype was significantly linked with vacA s1 and m1 genotypes and cagA-positive status. Inflammatory cell infiltration and atrophy scores were significantly higher in patients with hopQ type I strains than those with type II in Western patients. However, the hopQ type I genotype was not associated with an increased risk for peptic ulcer or gastric cancer, and had no additive effects to vacA genotypes or cagA-positive status. The expression of multiple putative virulence factors in Asian strains likely explains the relatively high incidence of clinical outcomes including gastric cancer compared with other parts of the world. Although hopQ genotype did not improve the predictive value above other genotyping for development of H. pylori-related gastroduodenal diseases, the hopQ genotype might be able to add a useful virulence marker for gastroduodenal diseases.