[Specific IgE in the gastric and duodenal mucosa. An epiphenomenon or pathogenetic mechanism of some forms of "peptic" ulcer?].

Allergic mechanisms have been shown to induce gastric and intestinal damage in animal models. It has been demonstrated that people allergic to food may complain of gastrointestinal disorders. Furthermore food allergens can induce gastric mucosal damage in sensitized people. Little is known as regards allergic mechanisms underlying "peptic" ulcers although there are reports suggesting that some forms of gastric and duodenal ulcer may be caused by allergy. AIM. Of the study was to evidence if IgE specific to food and inhalants are localized in gastric and duodenal mucosa and if the in vitro incubation of gastric and duodenal biopsies with specific allergens, stimulate mast-cell mediators. MATERIALS AND METHODS. Twenty-one patients affected by gastric/duodenal ulcers (14 with high total IgE serum levels) and 16 controls were studied. All patients were submitted to upper digestive endoscopy and biopsies were taken from gastric fundus, body and antrum and duodenal bulb. Specific IgE to food and inhalant allergens were tested after homogenization of biopsies, using commercial kits. In 3 selected patients, 3 biopsies from gastric fundus and 3 from duodenal bulb were taken. After incubation of mucosal of mucosal biopsies with allergens (wheat, lactoalbumin, Parietaria J. pollen), the release of histamine and tryptase was measured. The release of Pepsinogen A was measured in the same conditions, as control. RESULTS. Specific IgE to food and inhalants allergens have been found in 164/586 tests (27.9%) of "peptic" ulcer patients and in 17/430 tests (4%) of controls. The duodenal bulb resulted the site in which most frequently IgE have been found. The release of histamine and tryptase has been stimulated only in 1/6 tests by incubation of biopsies with specific allergens in patients with specific IgE. PG-A release has been always stimulated by incubation of gastric biopsies, but not duodenal biopsies, with all tested allergens. DISCUSSION AND CONCLUSION. Specific IgE may be localized in gastric and duodenal mucosa of patients with "peptic" ulcer and/or food allergy. This event is linked to high total IgE serum levels and in a lesser extent, intestinal parasitosis, it is not strictly correlated with specific IgE in the serum and it regards both food and inhalant allergens. No relevant effects were observed after incubation of specific allergens with gastric or duodenal mucosa biopsies containing specific IgE. The possibility that higher allergens concentration stimulate mediator release from mast cells should be investigated. A defect of the gastric or duodenal epithelial barrier which permit a passage way for proteins with subsequent IgE production in the submucosa, appears to be the cause of localization of specific IgE in stomach and duodenum.