Immunoglobulin E and eosinophilic cationic protein in segmental lavage fluid of the small and large bowel identify patients with food allergy

OBJECTIVE: Members of the general population often assume that they suffer from food allergy, but the true prevalence is low. Testing for the diagnosi s of food-related hypersensitivity entails laborious procedures, including GI endoscopy. Our objective was to develop an endoscopic screening approach for food allergy. METHODS: Endoscopically guided segmental lavage was performed in 11 patient s with GI allergy and in 20 controls during lower GI endoscopy of the termi nal ileum, the coecum, and the rectosigmoid. Eosinophilic cationic protein (ECP) and protein were measured in native lavage fluid, and immunoglobulin E (IgE) was also measured after a IO-fold lavage concentration. RESULTS: IgE/protein in lavage fluid from the coecum (0.055 +/- 0.068 U/mg vs 0.003 +/- 0.012 U/mg; p = 0.001) and the rectosigmoid (0.134 +/- 0.170 U /mg vs 0.019 +/- 0.042 U/mg; p < 0.05) was significantly elevated in patien ts: with GI allergy. ECP/protein was significantly elevated at the terminal ileum (22.95 +/- 37.67 <mu>g/mg vs 7.09 +/- 7.68 mug/mg: p < 0.05) and the rectosigmoid (23.66 +/- 19.33 <mu>g/mg vs 11.97 +/- 16.39 mug/mg; p < 0.05 ). The combined use of GI lavage IgE and ECP as a diagnostic test for food allergy resulted in a sensitivity of 91 % and a specificity of 80%. CONCLUSIONS: In endoscopically guided segmental lavage fluid, IgE and ECP/p rotein are increased in patients with food allergy. These measurements seem to offer an attractive diagnostic tool and may serve as a screening method . (C) 2001 by Am. Cell. of Gastroenterology.