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BackgroundBroncho-Vaxom® (OM-85 BV) is an extract of infectious respiratory bacteria that is used as an immunostimulant outside of the United States for the prevention and treatment of bronchitis and rhinosinusitis. Prior studies have shown that use of OM-85 BV is associated with reduction in frequency of respiratory infection and decreased duration of antibiotic usage. However, the effects of OM-85 BV on respiratory mucosal innate immunity are unknown.MethodsHuman sinonasal epithelial cells were grown at an air-liquid interface (ALI). Ciliary beat frequency (CBF) and nitric oxide (NO) production in response to stimulation with OM-85 BV was measured in vitro. Pharmacologic inhibitors of bitter taste receptor (T2R) signaling were used to determine if this pathway was taste-receptor-mediated.ResultsApical application of OM-85 BV resulted in an NO-mediated increase in CBF (p

Background: Ketotifen is a second‐generation noncompetitive H1‐antihistamine and mast‐cell stabilizer. It is commonly used to treat or prevent allergic conjunctivitis, asthma, chronic urticaria, anaphylaxis, mast‐cell, and other allergic‐type disorders. However, it has never been studied in aspirin‐exacerbated respiratory disease (AERD), an aggressive phenotype of chronic rhinosinusitis with nasal polyps, where the mast cell plays a prominent role its pathogenesis. Methods: Human sinonasal epithelial cells were grown at an air‐liquid interface (ALI). Ketotifen powder was dissolved in saline to make 4 test solutions at 1.04, 2.08, 10.4, and 20.8 µg/mL. Control (saline) or ketotifen solution was added apically to ALI cultures from tissue of 5 unique patients, and ciliary beat frequency (CBF) changes were recorded. Lactate dehydrogenase was measured at 24 and 48 hours to estimate long‐term cellular toxicity. Results: Apical application of ketotifen at all concentrations was neither ciliotoxic nor ciliostimulatory, with no change in CBF over a period of 15 minutes after application. Cellular toxicity for all concentrations at 24 and 48 hours after application was <3% and <7%, respectively, that of lysed cultures. Conclusion: Topical application of ketotifen to an in vitro model of sinonasal epithelium is safe, as evaluated by CBF and lactate dehydrogenase. Ketotifen is neither ciliotoxic nor ciliostimulatory, and no long‐term cellular toxicity was observed. Ketotifen may have promise as a topical nasal rinse in the treatment of AERD. [ABSTRACT FROM AUTHOR]