Single dose topical corticosteroid inhibits IL‐5 and IL‐13 in nasal lavage following grass pollen challenge

Background: Nasal lavage is a noninvasive method of obtaining inflammatory exudates following nasal allergen challenge (NAC), and permits cells and released mediators to be evaluated. Objective: To determine the effects of a single dose of topical steroid on eosinophils and levels of chemokines and cytokines in nasal lavage fluid following NAC in patients with allergic rhinitis. Methods: Patients with grass pollen seasonal allergic rhinitis ( n = 32) out of the allergy season received either nasal budesonide (100 μ g per nostril) or matched placebo before allergen challenge in a double blind two‐way crossover design. A semi‐automated mixed bead array system was employed to measure multiple chemokines and cytokines in small volumes (50 μ l) of nasal lavage supernatants. Results: Following NAC there was a rapid onset of nasal symptoms together with nasal eosinophilia, and the appearance of IL‐5 and IL‐13 in lavages between 4 and 8 h. Elevated levels of eotaxin, RANTES, IL‐8 and MCP‐1 were also detected following allergen challenge. A single dose of nasal budesonide caused a decrease in symptoms ( P < 0.05) and nasal eosinophils ( P < 0.05) with selective abrogation of IL‐5 and IL‐13 responses ( P < 0.05), but a lack of effect on levels of eotaxin, RANTES, IL‐8 and MCP‐1. Conclusion: This study suggests that a single dose of nasal steroid has the capacity to selectively abolish IL‐5 and IL‐13 responses following NAC. This model should be convenient for testing novel anti‐inflammatory and immunoregulatory agents intended for the treatment of allergic rhinitis.