Comparison of Histologic Methods for the Diagnosis of Pediatric Helicobacter pylori Infection

Abstract 641 Poster Session II, Sunday, 5/2 (poster 165)

Background: Helicobacter pylori infection is a major cause of gastritis in both adult and pediatric populations and may result in gastric malignancy later in life. When endoscopy and biopsy are used for diagnosis, occasionally histologic specimens demonstrate chronic inflammation in the face of a negative urease screening test. In this setting, a silver staining technique is often used to rule out H. pylori infection. Purpose: To compare silver staining to specific immunohistochemical staining of pediatric endoscopic gastric biopsy sections for the identification of H. pylori infection in the presence of chronic inflammation and a negative urease screening test (CLO test^R). Patients and Methods: Thirty-seven patients (ages 4 months to 21 years), whose gastric antral biopsies yielded a negative CLO test^R, but were positive for lymphocytic infiltration, were selected for a retrospective study. Specimens had been subjected to CLO test^R, hematoxylin and eosin staining, and Dieterle silver staining. Immunohistochemical staining specific for H. pylori was also performed. Nine additional patients whose gastric antral biopsies demonstrated chronic inflammation and a positive CLO test^R were used as controls. Results: With Dieterle staining, 8/37 (22%) urease-negative biopsies contained organisms morphologically compatible with H. pylori, 21/37 (57%) contained organisms not compatible with H. pylori, and 8/37 (21%) were negative for organisms. Immunostaining confirmed 6/8 (75%) Dieterle-positive cases as being positive for H. pylori, was negative in 2/8 (25%) Dieterle-positive cases, and was positive in 2/8 (25%) Dieterle-negative cases. Biopsies from 8/9 (89%) urease-positive specimens contained organisms seen with both Dieterle and immunohistochemical stains, and 1/9 (11%) was negative for both stains. One urease-negative biopsy was positive for H. pylori with both special stains. Conclusion: Although both stains yielded comparable results with H. pylori-positive biopsies, Dieterle staining was potentially confusing because of non-specific staining of other organisms. We recommend the use of immunohistochemical staining, rather than silver staining, in the evaluation of urease-negative gastric biopsies demonstrating chronic inflammation to diagnose H. pylori infection in children.