Comparison of Immunohistochemistry and Silver Stain for the Diagnosis of Pediatric Helicobacter pylori Infection in Urease-negative Gastric Biopsies

We compared immunohistochemical and silver stains of pediatric gastric biopsy sections for the identification of Helicobacter pylori infection with chronic inflammation and a negative urease screening test. Thirty-seven patients (age range 10 months to 21 years) whose gastric antral biopsies were negative for the rapid urease test (CLO^R) but positive for lymphocytic infiltration were selected for a retrospective study. Specimens had been subjected to a rapid urease test (CLO^R) and hematoxylin and eosin staining, and Dieterle silver staining and immunohistochemical staining specific for H. pylori were also performed. Twelve additional patients with ureasepositive biopsies were used as controls. With Dieterle staining, 8/37 (22%) urease-negative biopsies contained organisms morphologically compatible with H. pylori, 21/37 (56%) contained organisms not compatible with H. pylori, and 8/37 (22%) were negative for organisms. Immunostaining confirmed 6/8 (75%) Dieterle-positive cases as being H. pylori, was negative in 2/8 (25%) Dieterle-positive cases, and was positive in 2/8 (25%) Dieterle-negative cases. Biopsies from 8/12 (67%) urease-positive specimens contained organisms seen with both Dieterle and immunohistochemical stains, and 4/12 (33%) were negative with both stains. Although both stains yielded comparable results with H. pylori–positive biopsies, Dieterle staining was potentially confusing because of nonspecific staining of other organisms. A significant proportion of (CLO^R)-negative biopsies was positive for H. pylori with special stains. We therefore recommend the use of immunohistochemical staining rather than silver staining in the evaluation of urease-negative gastric biopsies demonstrating chronic inflammation in children.