Helicobacter pylori anti-CagA antibodies: prevalence in symptomatic and asymptomatic subjects in Turkey.

Abstract

Several reports have shown the prevalence of anti-CagA antibodies to be associated with the development of peptic ulcer diseases, while others have indicated that there is no such association. To examine the prevalence of antibodies to CagA and other Helicobacter pylori antigens in symptomatic and asymptomatic subjects in Turkey. subjects and Sixty-six symptomatic subjects, 16 to 74 years of age, were examined for H pylori by biopsy-based tests and ELISA. One hundred nineteen asymptomatic subjects, 20 to 65 years of age, were also tested serologically for the presence of H pylori. Samples from both groups that were found to be positive for H pylori by ELISA were then tested by immunoblotting. Fifty-four (82%) symptomatic subjects and 76 (64%) asymptomatic subjects were found to be H pylori-positive by ELISA. Samples from 30 symptomatic subjects who were found to be H pylori-positive by ELISA were analyzed by immunoblotting. Antibodies to CagA (116 kDa) antigen were detected in immunoblots of 11 of 14 (79%) with chronic gastritis, 12 of 13 (92%) with duodenal ulcer and three of three (100%) with gastric cancer. Antigens of the following molecular weights were also detected in these 30 subjects: 89 kDa (VacA) in 21 (70%), 37 kDa in 21 (70%), 35 kDa in 19 (63%), 30 kDa in 27 (90%) and 19.5 kDa in 19 (63%). Immunoblots of 40 ELISA-positive asymptomatic subjects showed that 33 (83%) had antibodies to CagA antigen, 26 (65%) to VacA antigen, 30 (75%) to a 37 kDa antigen, 30 (75%) to a 35 kDa antigen, 39 (98%) to a 30 kDa antigen and 36 (90%) to a 19.5 kDa antigen. Antibodies to CagA antigen were prevalent in both groups, regardless of the presence of gastroduodenal disease.