Mast cell tryptase levels in gut mucosa in patients with gastrointestinal symptoms caused by food allergy.

BACKGROUND AND AIMS Mast cells, which are important effector cells in food allergy, require a special histologic treatment for quantification in endoscopic gastrointestinal samples. The objective of this study was to investigate whether mast cell tryptase (T), a typical mast cell-associated marker, may help to detect patients with food allergy. METHODS Mast cell T was investigated from 289 colorectal samples of 73 controls, 302 samples from 43 patients with food allergy and gastrointestinal symptoms, and 72 samples from 12 patients with partial or complete remission of allergic symptoms. Endoscopically taken samples were immediately put into liquid nitrogen, mechanically homogenized by a micro-dismembrator with three homogenization steps and tissue T content (ng T/mg wet weight) was measured by fluoroenzyme immunoassay. RESULTS Tissue T levels from the lower gastrointestinal tract were significantly elevated (p < 0.0001) in patients with manifest gastrointestinal allergy (median: 55.7, range: 9.3-525.0) compared with controls (median: 33.5, range: 8.0-154.6). A subgroup of 12 patients with remission of allergy showed markedly decreased symptom scores and mucosal T levels after more than 1 year of antiallergic therapy (pretreatment median: 54.1, range: 37.0-525.0 and posttreatment median: 28.4, range: 19.8-69.1; p = 0.01). CONCLUSIONS High T levels in the gut of food-allergic patients support the role of stimulated mast cells or an increased mast cell number.