Association between efficient adhesion to HEp-2 cells and severity of gastritis in Helicobacter pylori strains isolated from children

Background and objectives: Helicobacter pylori causes chronic gastritis, peptic ulceration, and is a risk factor for gastric cancer. More than half of the world`s population is infected with this pathogen, however the disease outcome varies. Among the virulence factors of H. pylori, specific adhesions to gastric epithelium may be an important step in the induction of active inflammation. H. pylori displays considerable genetic diversity attributed to genetic drift during long-term colonization. Heterogeneity of clinical-isolates has considerably impacted in understanding the role of each factor in infection outcome. However, genetic change may be more limited in the stomach of children in the short period after infection. This work evaluates differences in adherence potential of strains isolated from children with various chronic- inflammation status. Materials and Methods: A total of 157 children admitted to Medical Center of Tehran for upper gastrointestinal problems underwent endoscopy for H. pylori infection. Histological examination of their biopsies was performed after H& E and Giemsa staining. Gastritis and inflammation were graded according to the updated Sydney system. 70 culture-positive children, 20 were selected according to their histopathological status. Adherence of their H. pylori isolates to HEp- 2 cells was evaluated by viable count of bacteria associated with host cells in an optimized procedure developed in this study. Results: Correlation was seen between inflammation severity score and efficiency of adhesion to HEp-2 cells. This correlation was not observed in the KB cell line as an epithelial cell-model. Conclusion: Specific interaction of H. pylori with host gastric epithelium may be associated with disease outcome