CFTR and cystic fibrosis: Since the amount of IL-1β reported in sputum of CF patients (2.8–32 ng/ml) [20] is higher than the lowest in vitro inhibitory dose of 2.5 ng/ml, the IL-1β present in lungs should be enough to down-regulate CFTR, and it might had profound negative effects on the already reduced amounts of ΔF508 CFTR able to reach the cell membrane.