Endogenous Protease Inhibitors in Airway Epithelial Cells Contribute to Eosinophilic Chronic Rhinosinusitis.

Cystatin A and SPINK5 play an important role in protecting the airway epithelium from exogenous proteases. The preservation of EPIs may have a therapeutic benefit in intractable airway inflammation, such as eosinophilic CRS.