Background: Eosinophil cationic protein (ECP) is one of the major, cytotoxic molecules produced by eosinophils, which can be used as a marker of allergic inflammation.
Objective: In this placebo-controlled study we measured nasal and serum ECP levels to verify their possible role in monitoring the efficacy of anti-inflammatory therapy in allergic chronic rhinitis in 38 children aged from 4 to 14yr, allergic to house dust mites.
Method: Nasal ECP, by the method of direct incubation on nasal mucosa, and serum ECP were determined before and after 3 weeks of treatment with flunisolide nasal spray 50 micrograms twice/daily (13 cases, Group 1), disodium cromoglycate (DSCG) 10.4 mg three times/day (15 cases, Group 2) and placebo (10 cases, Group 3). The effectiveness of therapy was evaluated clinically and correlated to serum and nasal ECP values.
Results: Before treatment no significant difference emerged in the clinical scores of the three groups of patients. Before and after treatment serum ECP levels were not statistically different from normal controls. Before treatment nasal ECP was significantly higher in all patients compared with controls (P < 0.001). Nasal ECP decreased significantly in flunisolide-treated patients (P < 0.01) (before therapy: median 111 micrograms/L, range from 33.6 to 200 micrograms/L; after therapy: median 36.8 micrograms/L, range from 2.6 to 196 micrograms/L), but not in DSCG-treated patients, (before therapy: median 66.2 micrograms/L, range from 32.3 to 200 micrograms/L; after therapy: median 60.4 micrograms/L, range from 7.9 to 144 micrograms/L). No significant variation was present in the placebo group. Clinical improvement was statistically significant after flunisolide therapy (P < 0.05), less evident after DSCG (P = 0.06).
Conclusion: Serum ECP in chronic allergic rhinitis has been shown to be not useful in monitoring allergic inflammation, but nasal ECP, determined by mucosal incubation, may be used to evaluate the activity of eosinophils and monitor the anti-inflammatory efficacy of therapy in chronic rhinitis.