Interleukin-1 beta is a potential mediator of airway nitric oxide deficiency in cystic fibrosis.

Airway nitric oxide (NO) deficiency is a hallmark of cystic fibrosis (CF), but the reasons for the reduced NO production in CF airways are unclear. Interleukin (IL)-1 pathway activation plays a role in early CF lung disease and is also involved in the regulation of NO synthase activity. Treatment of CF patients with the CFTR-targeting drug ivacaftor, among other beneficial effects, results in an increase in airway NO levels. In this longitudinal observational trial, we show that ivacaftor therapy leads to a significant reduction in sputum IL-1β concentration but not in other IL-1- or Th17-associated cytokines. IL-1β concentrations were closely linked to improvement in pulmonary function, measures of NO metabolism in sputum and exhaled NO. These data therefore suggest a potential interaction between transepithelial chloride conductance, IL-1β and airway NO production.