Evaluation of neutrophil elastase/ alpha-1-antitrypsin ratio in different stages of chronic obstructive pulmonary disease (COPD) patients

Introduction: Little is known about protease, anti-protease markers in chronic obstructive pulmonary disease (COPD) patients. Objectives: The objective of present study was to identify and try to correlate serum markers of protease and anti-protease with pulmonary functions in different stages of patients with COPD and to determine the ratio of neutrophil elastase/alpha-1-antitrypsin in different stages of COPD patients. Methods: This prospective observational study was carried out in patients with stable COPD. Activities of serum alpha-1-antitrypsin and neutrophil elastase were measured in 220 stable COPD patients and in 60 healthy controls by ELISA method. 220 COPD patients were divided into 4 stages according to severity: stage I, II, III and IV. Results: An increase in serum neutrophil elastase and neutrophil elastase/alpha-1-antitrypsin ratio was observed in COPD patients with the advancement of the stage. In contrast to that, decreased activity of alpha-1-antitrypsin in serum was observed in different stages of COPD and is correlated positively with lung function parameters. Conclusion: From these findings we conclude that as the severity increases there is decrease in alpha-1-antitrypsin resulting in concomitant increase in neutrophil elastase activity causing imbalance between protease-antiprotease in COPD patients and this imbalance is associated with impairment of lung function. The neutrophil elastase/ α-1-antitrypsin ratio can tell us the severity of the chronic obstructive pulmonary disease it may be in terms of increased fibrosis of the lung. Though the magnitude of neutrophil elatase/alpha-1-antitrypsin ratio is minute, still it can be a good marker of pulmonary function in term of severity of the COPD.