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 biop sy sections for the identification of Helicobacter pylori infection with ch ronic inflammation and a negative urease screening test. Thirty-seven patie nts (age range 10 months to 21 years) whose gastric antral biopsies were ne gative for the rapid urease test (CLOR) but positive for lymphocytic infilt ration were selected for a retrospective study. Specimens had been subjecte d to a rapid urease test (CLOR) and hematoxylin and eosin staining, and Die terle silver staining and immunohistochemical staining specific for H. pylo ri were also performed. Twelve additional patients with urease-positive bio psies were used as controls. With Dieterle staining, 8/37 (22%) urease-nega tive 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%) Dieter le-positive cases as being H. pylori, was negative in 2/8 (25%) Dieterle-po sitive cases, and was positive in 2/8 (25%) Dieterle-negative cases. Biopsi es 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. p ylori-positive biopsies, Dieterle staining was potentially confusing becaus e of nonspecific staining of other organisms. A significant proportion of ( CLOR)-negative biopsies was positive for H. pylori with special stains. We therefore recommend the use of immunohistochemical staining rather than sil ver staining in the evaluation of urease-negative gastric biopsies demonstr ating chronic inflammation in children.