While subacute and chronic CS and CSC exposure is associated with impaired CFTR function and constitute major risk factors for COPD, CF, and other lung diseases8,70, our knowledge of the short-term CSC impact on the ion transport of respiratory epithelia, a critical determinant of the ASL homeostasis and mucociliary transport (MCT), is incomplete. The gene discussed is CFTR; the disease is cystic fibrosis.