HIGH PREVALENCE OF CYTOTOXIN POSITIVE HELICOBACTER-PYLORI IN PATIENTSUNRELATED TO THE PRESENCE OF PEPTIC-ULCERS IN JAPAN

Background-It has been reported that infection with vacuolating cytoto xin positive Helicobacter pylori strains is associated with gastroduod enal disease in Western countries. Aims-To evaluate the prevalence of cytotoxin producing strains among patients with H pylori infection in relation to gastrointestinal diseases in Japan. Patients-Ninety seven patients undergoing endoscopy. Methods-A Western blot assay was conduc ted to detect serum antibodies against the cytotoxin using recombinant cytotoxin (VacA protein) as an antigen. To obtain a purified recombin ant cytotoxin, the vacA gene (2233 nucleotides) was cloned into an exp ression vector to produce the protein (744 amino acids), which was exp ressed in Escherichia coli. Results-Serum IgG antibodies to the cytoto xin were present in 85%, 95%, 95%, and 100% of infected patients with gastric ulcer (n=26), duodenal ulcer (n=21), chronic gastritis (n=19), and endoscopically normal mucosa (n=14), respectively. Conclusion-the western blot method using recombinant VacA protein is simple and usef ul for detecting antibody to vacuolating cytotoxin. This method showed antibodies against cytotoxin were highly prevalent, even in subjects with endoscopically normal mucosa in Japan, indicating that the cytoto xin may not be an independent cause of gastrointestinal diseases induc ed by H pylori infection.