Altered NaCl concentration of airway surface liquid in cystic fibrosis

A novel isotopic technique suggests that the [Na] and [Cl] of airway surfac e liquid are both normally similar to 50 mM. In cystic fibrosis, lack of th e functional cystic fibrosis transmembrane conductance regulator (CFTR) cau ses failure of transcellular Cl absorption, resulting in an elevation of [N a] and [Cl] of airway surface liquid to similar to 100 mm.