CFTR and cystic fibrosis: Indeed, unlike IL-1alpha, we could not find IL-1beta in the supernatants of NCI-H292 cells treated with CFTR-172 or in the supernatants of IB3 cells in the constitutive state (lower limit of detection approximately 4 pg/ml), similar to a recent study that reported no IL-1beta production in CF airway epithelial cells in the constitutive state or after exposure to Pseudomonas products [48].