Given that COPD and CF have known defects in CFTR (Cystic fibrosis transmembrane conductance regulator) anion channel regulation and that even mild defects in this pathway (in the case of adult‐onset CF) are sufficient to induce chronic airway disease, we hypothesized that there may be an induced dysfunction in this pathway in severe non‐eosinophilic asthma. This evidence concerns the gene CFTR and cystic fibrosis.