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In Diffuse Atrophic Gastritis, Routine Histology Underestimates Helicobacter pylori Infection

Background Histologic detection of Helicobacter pylori shows high diagnostic accuracy in chronic nonatrophic gastritis. However, when atrophy occurs, the sensitivity of bacterial detection varies. This study assessed the routine histologic sensitivity for current H. pylori infection in patients with atrophic gastritis, with and without intestinal metaplasia. Study Five hundred and ten consecutive patients with diffuse chronic atrophic gastritis, with (174 cases) and without (336 cases) intestinal metaplasia, were investigated following the Sydney System recommendations. In cases with negative tissue staining for Helicobacter-like organisms, serum immunoglobulin G (IgG) antibodies to H. pylori were assayed. Results The overall rate of positive staining for Helicobacter-like organisms was 51.8% (264 of 510 cases), 62.8% and 30.4% in cases without and with intestinal metaplasia, respectively. Serum IgG antibody determination was consistent with current infection in 180 (73.2%) of the 246 cases with negative histology. H. pylori detection rate was significantly lower (p < 0.01) in Grade 3 than in Grade 1 atrophy. When intestinal metaplasia was present, histologic bacterial detection progressively decreased, from 46.3% to 20%, depending on severity. H. pylori infection was found by histology in 42.2% and in 56.2% of cases with inactive and active disease, respectively. Overall, the diagnostic accuracy of histology was significantly lower (p <0.001) than that of histology combined with serology. Conclusions Most (87.1%) diffuse chronic atrophic gastritis patients showed serum antibody IgG levels consistent with current H. pylori infection, although histology was positive in only 59.5% of cases. Gastritis activity and current H. pylori infection did not ever correlate in the presence of mucosal atrophy and/or intestinal metaplasia. Routine biopsy sampling, hematoxylin and eosin staining, and Giemsa staining therefore underestimated the true prevalence of H. pylori infection.