Serum Anti-Helicobacter pylori IgG Antibody Titer in H. pylori-negative Cases with a Different Gastric Mucosal Atrophy Status.

Objective This retrospective study was performed to investigate the anti-Helicobacter pylori IgG antibody serum titers in H. pylori-negative subjects with different degrees of gastric mucosal atrophy including C0 grade atrophy. Methods The absence of H. pylori infection was determined based on both negative serum anti-H. pylori IgG antibody test findings and no endoscopic evidence of that infection. Cases negative for the antibody and with positive endoscopic findings of H. pylori infection were defined as H. pylori-positive. The serum anti-H. pylori IgG antibody titers were analyzed in H. pylori-negative (n=1,087), -positive (n=69), and post-eradicated (n=278) subjects. Results The serum antibody titer in subjects with H. pylori-positive endoscopy findings was significantly higher than that in H. pylori-negative subjects, even when the serum titer indicated a negative result. In addition, the anti-H. pylori IgG antibody serum titer was higher in H. pylori-negative subjects with a greater degree of gastric mucosal atrophy. In a comparison between H. pylori-negative C0 and C1 gastric mucosal atrophy cases, the antibody serum titer in those classified as C0 was significantly lower. An analysis of H. pylori post-eradicated cases showed that the serum antibody titer decreased over time after successful eradication. Conclusion The disappearance of H. pylori infection in H. pylori-negative individuals may occur later in those with a greater degree of gastric mucosal atrophy. The serum antibody titer difference between the H. pylori-negative C0 and C1 groups might have been caused by the differences in distribution between H. pylori-uninfected subjects and those in whom the infection had disappeared, thus additional investigation is needed to clarify the significance of gastric mucosal classification including the C0 grade.