ABH and Lewis antigen distributions in blood, saliva and gastric mucosa and H pylori infection in gastric ulcer patients

AIM:To investigate the ABH and Lewis antigen expres- sion in erythrocytes,saliva and gastric epithelium,as well as the association between H pylori and the pres- ence of gastric epithelial lesions. METHODS:The distribution of ABH and Lewis blood group antigens in erythrocytes,saliva and gastric mu- cosa of H pylori-infected gastric ulcer patients was ana- lyzed.Forty-two patients with gastric ulcer were studied, and fifty healthy individuals were used as control group. The blood group antigens were determined by direct hemagglutination,dot-ELISA and immunohistochemi- cal methods in erythrocytes,saliva and gastric mucosa specimens,respectively.Diagnosis for H pylori infection was performed by conventional optical microscopy and ELISA. RESULTS:A higher seroprevalence of IgG H pylori spe- cific antibodies was observed in gastric ulcer patients (90%)compared to the control group(60%).We ob- served a significant increase of phenotypes O,A_2 and Lewis b in H pylori-infected patients.The expression of these antigens had progressive alterations in areas of ul- cerous lesions and intestinal metaplasia. CONCLUSION:ABH and Lewis blood group antigens are a good indicator for cellular alterations in the gastric epithelium.