HELICOBACTER-PYLORI (HELICOBACTER-PYLORI) IN GASTRIC-MUCOSA OF CHILDREN WITH ABDOMINAL COMPLAINTS - IMMUNOHISTOCHEMISTRY DETECTS ANTIGEN-REACTIVE CORPUS MUCOSA CELLS

Background. Previous morphological and serological studies of gastric Helicobacter pylori (H. pylori) colonization among Estonian children w ith abdominal complaints, as well as among populations of schoolchildr en, have shown a high prevalence of H. pylori (49-60%). Based on publi shed data concerning the high specificity and sensitivity of immunohis tochemical detection of H. pylori, we examined the prevalence of H. py lori in gastric biopsy specimens of Estonian children by different loc alization and morphological type of gastritis comparing Giemsa stainin g with immunohistochemistry. Material and Methods. Formalin-fixed biop sies (107 antral, 108 corpus mucosa) of 112 children (41 boys, 71 girl s, age range 1-16 years, median age 12 years) with abdominal complaint s were stained with hematoxylin & eosin and Giemsa stains, as well as examined using the peroxidase antiperoxidase (PAP) method with polyclo nal antibodies to H. pylori. Results. Gastritis of any degree and loca lization was found in 84/112 (75%) children. Using Giemsa staining H. pylori were detected in 83/112 (74%) of all children, and by use of th e PAP method in 55/112 (49%) (p = .001). Concordance of the results of immunohistochemical and Giemsa methods in antrum biopsies was 70%, in corpus biopsies 73%. In 12 out of 108 (11%) corpus mucosa specimens a positive staining with anti-H. pylori IgG was localized in the cytopl asma of corpus mucosal cells in the neck part of the glands. Conclusio ns. The prevalence of H. pylori was higher when employing the Giemsa s tain in comparison with immunohistochemistry. Antibody reactivity of c ells in the neck part of the corpus glands may either be due to cross- reactivity of anti-H. pylori Ige with epithelial cell epitopes, or to internalization of H. pylori by these cells, suggesting a pathogenic r ole of neck cells in an anti-H. pylori immune response.