Helicobacter pylori infection in subjects negative for high titer serum antibody

AIM To investigate the clinicopathological features of the patients testing negative for high titer serum antiHelicobacter pylori (H. pylori) antibody. METHODS The antibody titers were measured using antigens derived from Japanese individuals. 13C-urea breath test-positive individuals were defined as having H. pylori infection. We investigated the demographic characteristics, laboratory data, endoscopic findings including Kyoto classifcation of gastritis, and histology in negative-high titer patients without H. pylori eradication therapy. Kyoto classification consisted of scores for gastric atrophy, intestinal metaplasia, enlarged folds, nodularity, and redness. RESULTS Of the 136 subjects enrolled, 23 (17%) had H. pylori infection. Kyoto classification had an excellent area under the receiver operating characteristics curve (0.886, 95% confdence interval: 0.803-0.968, P = 3.7 × 10-20) for predicting H. pylori infection with a cutoff value of 2. Further, Kyoto classification, H. pylori density, and neutrophil activity had high accuracies (89.7%, 96.3%, and 94.1%, respectively). Kyoto classifcation was independent of the demographic and laboratory parameters in multivariate analysis. CONCLUSION Endoscopic Kyoto classification of gastritis is a useful predictor of H. pylori infection in negative-high titer antibody patients.