Histological predictors of active Helicobacter pylori infection.

Helicobacter pylori is a common cause of gastritis. No single test is 100% accurate for H. pylori diagnosis. In order to determine whether the presence of typical histological features of H. pylori gastritis may yield diagnostic information, we compared antral histology by H & E stain to the presence of organisms as detected on Thiazine stain of antral specimens, CLOtest, urea breath test and anti-H. pylori serology in 50 consecutive patients. Patients were diagnosed as having active H. pylori infection if at least two of these tests were positive. Patients with only one test positive (N = 5) were considered indeterminate for H. pylori and were excluded, resulting in 19 patients (42%) being classified as H. pylori positive. All slides were reviewed by a single blinded expert gastrointestinal pathologist and graded 0 (none) to 3 (severe) for the presence of acute (polymorphonuclear cells) or chronic (lymphocytes, monocytes, plasma cells) inflammation, lymphoid aggregates, and intestinal metaplasia. Active infection was associated with the presence of both acute and chronic inflammation (P < 0.0001) but not lymphoid aggregates (P = 0.09) or intestinal metaplasia (P = 0.10). The best positive predictors of infection were the presence of any acute inflammation (PPV = 86%) and the combination of any acute and chronic inflammation (PPV = 92%). The best negative predictor was absence of chronic inflammation (NPV = 100%). The presence of moderate to severe (grade 2 or 3) acute or chronic inflammation were each 100% predictive of infection. Moderate to severe chronic inflammation had both 100% sensitivity and specificity for active H. pylori infection, while moderate to severe acute inflammation was only 26% sensitive but 100% specific. The presence of any acute, or the combination of acute and chronic gastritis, is predictive of active H. pylori infection. Moreover, the predictive value correlates closely with the severity of the inflammation. The absence of chronic inflammatory cells rules out active H. pylori infection. These findings support the use of H & E histology-determined features in conjunction with other tests to diagnose H. pylori infection.