Finally, epithelial inflammation control is dysregulated in COPD (Barnes, 2016), with increased intraepithelial neutrophils (Eapen et al, 2017) and sputum TNF-α, IL-8/CXCL-8, and neutrophils (Keatings et al, 1996; Rutgers et al, 2000). Here, TNF is linked to chronic obstructive pulmonary disease.