Effect of topical corticosteroids on allergic airway inflammation and disease severity in obstructive sleep apnoea

Summary: Background: The incidence of sleep-related breathing disorders is correlated with lower and upper airway inflammatory diseases, such as asthma and allergic rhinitis. We hypothesized that corticosteroids treatment would lead to a greater reduction in disease severity in obstructive sleep apnoea syndrome (OSAS) patients with concomitant allergic rhinitis vs. non-allergic OSAS patients by reducing the level of inflammation in upper airway tissues. Objective: This study was performed to determine whether treatment with intranasal corticosteroids could reduce upper airway inflammation and improve sleep parameters in obstructive sleep apnoea syndrome patients with or without concomitant allergic rhinitis. Methods: Obstructive sleep apnoea syndrome patients with (n = 34) or without (n = 21) documented allergic rhinitis voluntarily enrolled in the study and were assessed at baseline and after corticosteroids treatment for 10-12 weeks. Sleep studies were performed and biopsies were obtained from the inferior turbinate, nasopharynx, and uvula. The apnoea-hypopnoea index, sleep quality, and level of daytime alertness were determined, and immunocytochemistry was used to phenotype tissue inflammation. Results: Standard sleep indices improved following treatment in the entire cohort of obstructive sleep apnoea syndrome patients, with greater improvement seen in the allergic rhinitis group. Allergic rhinitis patients demonstrated significantly improved O₂ saturation and a lower supine apnoea-hypopnoea index score after corticosteroid treatment; similar improvements were not seen in the non-allergic rhinitis group. Eosinophilia was detected at all three sites in the allergic rhinitis group, but not in the non-allergic rhinitis group. Following treatment, fewer eosinophils and CD4 lymphocytes were documented at all three biopsy sites in the allergic group; the reduction in inflammation was less apparent in the non-allergic rhinitis group.