ASSOCIATION OF CYTOTOXIN PRODUCTION AND NEUTROPHIL ACTIVATION BY STRAINS OF HELICOBACTER-PYLORI ISOLATED FROM PATIENTS WITH PEPTIC-ULCERATION AND CHRONIC GASTRITIS

Background-Helicobacter pylori is associated with neutrophil infiltrat ion within the gastroduodenal mucosa. Neutrophil activation provides a major source of oxygen free radicals, which have been implicated in t he pathogenesis of peptic ulceration. Aim-To investigate if cytotoxin producing strains of H pylori are associated with the generation of ox idative burst in polymorphonuclear neutrophils (PMNs).Patients-76 pati ents undergoing endoscopy of whom 45 had peptic ulcer and 31 chronic g astritis only were studied. Methods-Strains of H pylori were cultured in Brucella broth. After 48 hours, bacteria were harvested by centrifu gation and a bacterial suspension prepared as a stimulus for PMN oxida tive burst using chemiluminescence. PMNs were prepared from healthy bl ood donors. To test the ability of strains to produce cytotoxin, cultu re supernatants of each were concentrated by polyethylene glycol and t ested on cultured Vero cells for intracellular vacuolation. Results-30 of 45 (66 . 7%) peptic ulcer patients induced cell vacuolation versus nine of 31 (29%) strains from patients with chronic gastritis only (p <0 . 01). Cytotoxin positive strains of H pylori regardless of the pre sence or absence of peptic ulcer displayed an increased induction of r espiratory burst in PMNs compared with toxin negative strains from pat ients with chronic gastritis only (p<0 . 05). Among the toxin negative strains, those from patients with peptic ulcer did not show a signifi cant increase of the oxidative burst than those from patients without peptic ulcer (NS). Conclusion-Toxinogenicity of strains of H pylori se ems to be correlated with neutrophil respiratory burst and peptic ulce ration. The ability of some strains of H pylori to produce cytotoxin a nd to induce the oxidative burst in neutrophils may be important in th e pathogenesis of peptic ulcer disease.