Effect of fluticasone propionate aqueous nasal spray on allergen-induced inflammatory changes in the nasal airways of allergic rhinitics following exposure to nitrogen dioxide

Background The authors have recently demonstrated that prior exposure for 6 h to 400 p.p.b, nitrogen dioxide significantly enhances the early phase re sponse of eosinophils in the nasal airways of allergic rhinitics to subsequ ent allergen provocation. Objective To investigate whether treatment with f luticasone propionate aqueous nasal spray (FP) can alter the inflammatory r esponse in the nasal airways under these conditions. Methods Sixteen allergic, rhinitic patients were recruited for this double- blind, randomized, cross-over study and received either topical FP 200 mu g once daily or matched placebo for 4 weeks. At the end of treatment, all un derwent nasal lavage followed by a 6 h exposure to 400 p.p.b. NO2. Followin g exposure to NO2, nasal allergen challenge was performed and nasal lavage repeated. After a 4 week washout period, patients were given alternate trea tment and tested as above. Results Analysis of eosinophil cationic protein (ECP) in lavage samples fro m patients treated with placebo, demonstrated that this was significantly i ncreased from a median value of 2.3 ng/mL (range:l.0-7.1) to 15.1 ng/mL (ra nge: 1.5-40.0; P = 0.001) following exposure to NO2 and allergen challenge. However, in patients treated with FP, ECP concentrations only increased fr om 3.3 ng/mL (range: 0.2-9.2) to 5.1 ng/mL (rang: 0.3-0.0; P = 0.034) follo wing exposure to NO2 and allergen challenge. The difference of the changes in ECP concentration between the placebo and the FP-treated group was signi ficant (P = 0.003). Similarly, there was a significant increase in the numb er of eosinophils in nasal lavage after exposure to NO2 and allergen challe nge in the placebo group, and this increase was inhibited in FP group (P = 0.002). Conclusion These results suggest that FP influences NO2 and allergen-induce d changes in eosinophil function, as well as eosinophil number in the nasal airway of allergic rhinitics.