Proinflammatory activation of neutrophils and monocytes by Helicobacter pylori in patients with different clinical presentations

Abstract

Chronic Helicobacter pylori infection is associated with mucosal inflammation. The aim of the present study was to assess human neutrophil and monocyte activation by H. pylori strains obtained from patients with different clinical presentations. Bacterial sonicates from 12 strains were used to stimulate phagocyte upregulation of CD11b/CD18 adherence molecules assessed by fluorescence flow cytometry and oxidative burst responses assessed by chemiluminescence. A dose-dependent activation of CD11b/CD18 adherence molecules was observed with all strains on both neutrophils and monocytes. The activities were similar for strains from patients with duodenal ulceration and for strains from asymptomatic volunteers irrespective of histopathologic grades of the biopsy specimens from the antral mucosa. The neutrophil chemiluminescence response correlated with histopathologic severity. We conclude that upregulation of neutrophil and monocyte adherence molecules by H. pylori sonicates is not associated with clinical presentation of the infection.

FIG. 1

Upregulation of CD11b/CD18 on neutrophils (solid symbols) and monocytes (open symbols) activated for 30 min by H. pylori sonicate proteins. The results are expressed as the mean fluorescence intensities (MFI) from seven strains isolated from duodenal ulcer patients (squares) and from five strains from volunteers with asymptomatic gastritis (triangles) defined by endoscopy. The results represent mean values from 10 experiments ± standard deviations.

FIG. 2

Neutrophil and monocyte oxidative burst response upon fMLP stimulation after preincubation with sonicates from H. pylori strains isolated from seven subjects with mild to moderate gastritis (M/M) and from five subjects with severe gastritis (S). Results are expressed as neutrophil or monocyte response with fMLP treatment or without (i.e., after preincubation in sonicate or after preincubation in medium). Each strain was examined by using cells from four to six different healthy volunteers, and the results are expressed as the mean value from the results for each strain (horizontal bars indicate median values).