TNF and chronic obstructive pulmonary disease: In COPD, CS exposure damages the AE, as thoroughly described previously, inducing the release of DAMP (e.g., IL-1α, HMGB1), proinflammatory cytokines (IL-8/CXCL-8, IL-6, TNF-α), antimicrobial peptides such as LL-37, as well as profibrotic growth factors (TGF-β) (Pouwels et al., 2016; Di Stefano et al., 2018).