SERPINA1 and chronic obstructive pulmonary disease: As suggested in research, the Th17 cell proportion and COX-2 expression in the lung tissue and peripheral blood of COPD patients significantly increase, the inflammatory cytokine TNF-α levels in blood and airway elevate, the neutrophil elastase level in serum elevates, α1-AT level decreases, and the protease/antiprotease balance is destroyed [49–53].