Pro-inflammatory cytokines such as TNF-α, IL-1β, IL-6 and IL-8 are elevated in the airways of CF patients compared with the airways of healthy controls [127,128,129,130], while the secretion of cytokines involved in resolution of inflammation, such as IL-10, is reduced [128]; importantly, these differences correlate with the number of AMs. Here, TNF is linked to cystic fibrosis.