The ABM of Ceresa et al. [40] focused on emphysema progression (excess degradation of collagen) in chronic obstructive pulmonary disease and considered the transition of macrophages between the M1 and M2 phenotypes, secretion of TGF-β from M2 macrophages, recruitment of fibroblasts by TGF-β, fibroblast-mediated collagen deposition, and collagen degradation by MMP9. This evidence concerns the gene TGFB1 and chronic obstructive pulmonary disease.