Overexpression of co-stimulatory molecules in peripheral mononuclear cells of Helicobacter pylori-positive peptic ulcer patients: possible difference in host responsiveness compared with non-ulcer patients.

BACKGROUND/AIM: Helicobacter pylori is the principal cause of gastritis and peptic ulcer disease. However, H. pylori-positive patients do not always have peptic ulcer. This study was carried out in order to determine the difference in host immune reaction to H. pylori between patients with peptic ulcer and those without.
METHODS: Ten H. pylori-positive patients with peptic ulcer, 10 H. pylori-positive non-ulcer patients, and 10 healthy volunteers were examined for expression of surface molecules in peripheral blood mononuclear cells. The surface molecules were stained with immunofluorescence-labelled specific antibodies and analysed by flow cytometry.
RESULTS: More mononuclear cells expressed molecules ICAM-1, VLA-4, Leu-M3 in H. pylori-positive ulcer patients than in non-ulcer patients and healthy volunteers. There were also more cells expressing CD28, SLe(x), CD4, HLA-DR, and NU-B2 in H. pylori-positive ulcer patients than in non-ulcer patients and healthy volunteers. There were fewer cells expressing CD8 in H. pylori-positive ulcer patients than in non-ulcer patients and healthy volunteers.
CONCLUSION: H. pylori infection may cause immunological reactions which are reflected in peripheral mononuclear cells. However, the activity and characteristics of peripheral mononuclear cells, in terms of expression of adhesion molecules, may differ between ulcer and non-ulcer patients who are infected with H. pylori.