The role of leukocyte lysosomal elastase in the pathogenesis of obstructive lung disease

It is recognized that a potential source of proteolysis leading to pulmonary parenchymal destruction is present in polymorphonuclear leukocytes. However, measurements of leukocyte lysosomal elastase have not been reported in a large population of patients with chronic obstructive pulmonary disease (COPD) as compared with controls. Lysosomal elastase activity was measured in a leukocyte homogenate isolated from peripheral venous blood in 42 patients with COPD. 35 patients have MM Pi phenotype as did all 31 controls; 7 patients and 9 subjects with normal pulmonary function tests have abnormal Pi phenotypes. Mean age of each of the 3 groups is 57 ± 14, 43 ± 13, and 36 ± 20 yr, respectively. Elastase activity was assayed against solubilized bovine ligamentum nuchae elastin. The average of elastase activity in COPD patients with MM phenotype was 1191 mu/μg lysomal protein ± s.d. 598 as compared with 793 ± s.d. 242 in controls p