CFTR and cystic fibrosis: Our data could have important implications in CF as well, since recent studies suggest substantial overlap between COPD and CF due to CFTR dysfunction [1, 2, 11, 12, 17, 33]. Hypertonic NaCl has long been used in the treatment of CF and is known to improve lung function and to have marked benefits regarding exacerbations [25, 34–36].