TNF and cystic fibrosis: IL-8 is produced by macrophages and bronchial epithelial cells in the CF lung in response to infectious (i.e., Pseudomonas aeruginosa and Staphylococcus aureus) and inflammatory (i.e., IL-1β or tumor necrosis factor-α, TNF-α) stimuli via different signaling pathways (i.e., NF-κB) [73,74].