In vitro release of neutrophil elastase, myeloperoxidase and beta-glucuronidase in patients with emphysema and healthy subjects.

Evidence is accumulating that cigarette smoking plays an important role in the protease-antiprotease imbalance in alpha 1-antitrypsin-sufficient emphysema. Since most smokers, however, do not develop emphysema, it has to be presumed that other factors in addition to smoking contribute to the origin of the imbalance. The major source of proteases is the polymorphonuclear leucocyte (PMN). We tested the hypothesis that an abnormality in the releasability of PMN might predispose for the development of emphysema. Therefore, the release of elastase, myeloperoxidase, and beta-glucuronidase from PMN was investigated in patients with emphysema and healthy controls, matched for sex, age, and smoking habits. PMN were isolated from peripheral blood and stimulated with calcium-ionophore A23187, formyl-methionyl-leucyl-phenylalanine (FMLP), and serum-treated zymosan (STZ). Total enzyme content of PMN was measured after cell lysis with Triton X-100. Total elastase, myeloperoxidase, and beta-glucuronidase content of PMN were not significantly different in healthy subjects and patients with emphysema. In vitro release of elastase and myeloperoxidase from both stimulated and unstimulated PMN was not significantly different in healthy subjects and emphysematous patients. Moreover, no differences were found between smoking and ex-smoking individuals. Beta-glucuronidase release tended to be lower in patients with emphysema than in healthy controls. We conclude that an abnormality in the releasability of peripheral PMN is unlikely to be a pathogenetic factor in emphysema.