ATG7 and chronic obstructive pulmonary disease: Electron microscopy revealed an increase in the number of autophagosomes and the expression of autophagy proteins LC3B-II, Atg4, Atg5-12, and Atg7 in lung tissues from COPD patients compared with controls.[46] Increased LC3 expression in alveolar macrophages isolated from smokers is associated with impaired autophagic flow[47]; autophagy is similarly elevated in lung tissue of patients with COPD due to α1-trypsin insufficiency in some nonsmokers.