CTSG and chronic obstructive pulmonary disease: The results could be explained by the literature that suggests inflammation leads to the recruitment of neutrophils and eosinophils, which in turn, upon activation, result in the release of matrix metalloproteinase, myeloperoxidases, elastase, proteinases, and cathepsin G, all implicated in airway inflammation, tissue destruction, and thus playing a role in the pathophysiology of COPD.