Eosinophil cationic protein and specific IgE in serum and nasal mucosa of patients with grass‐pollen‐allergic rhinitis and asthma

BACKGROUND: After allergen exposure, IgE-bearing mast cells surface in respiratory mucosa. Eosinophils are also recruited locally by chemotactic mediators; they are the main cell directly involved in the late phase of allergic inflammation. IgE antibody and eosinophil cationic protein (ECP) are routinely determined mainly in serum although they exert their pathogenetic role more directly on mucosal surfaces. METHODS: We performed a comparative study of IgE antibody to grass and ECP on nasal mucosa and blood samples in order to evaluate the relevance of monitoring allergic inflammation in the target organ. Thirty-one patients and 10 nonatopic controls were enrolled in the protocol. Twenty-six subjects allergic to grass, 11 with rhinitis (group 1) and 15 with asthma and rhinitis (group 2), completed the study. Five patients dropped out. Specific IgE to grass and ECP was determined in nasal mucosa by our method based on in situ incubation. RESULTS: Serum IgE to grass did not increase during the pollen peak, as did nasal IgE, in group 1 from before the pollen peak, from 2.3 to 3.2 kU/l (P=0.02), and in group 2 at the pollen peak, from 4.8 to 12.2 kU/l (P=0.01). Serum ECP did not show any significant variation in group 1, but it increased at pollen peak from 6 to 11.2 microg/l (P=0.01) in group 2. Nasal ECP increased significantly in both groups even before the pollen peak. In group 1, ECP values rose from 15 to 39.9 microg/l (P=0.01). In group 2, ECP increase was much higher than in group 1, from 9 to 213 microg/l (P=0.001). Serum eosinophils, like nasal ECP, showed a significant increase of values from before the pollen peak in both groups, without correlation with serum ECP in rhinitic patients. CONCLUSIONS: Both specific IgE and ECP in the nasal mucosa showed a better correlation with allergen exposure than serum evaluations. With an appropriate method, allergic inflammation may be best monitored in the nasal mucosa.