As ENaC-mediated Na+/fluid absorption is increased in CF airways and because this abnormality contributes to airway surface liquid depletion, an important mechanism in the pathogenesis of CF lung disease (Mall 2009), it has been hypothesized that upregulation of BPIFA1 may counteract the basic defect and improve impaired airway surface hydration in CF (Garcia-Caballero et al. 2009). Here, BPIFA1 is linked to cystic fibrosis.