Abstract
In this study, we measured the elastase activity in the bronchoalveolar lavage fluid (BALF) and determined the source of elastase.
The elastase activity was determined by two different techniques SAPNA hydrolysis and elastolysis. BALF from 10 of 12 patients with chronic respiratory tract infections showed SAPNA hydrolytic activity and nine of these patients also demonstrated elastin solubilization in an elastin agar plate. However, nonsmokers (n=8), smokers (n=10) and fibrosis patients (n=10) did not show any elastase activity in BALF.
More than 90 percent of SAPNA hydrolytic activity in BALF was inhibited by DFP treatment, but about 80 percent of activity remained after EDTA treatment. Both results revealed that the elastase in BALF was a serine protease and its source might be neutrophils.
The elastase activity in BALF was especially elevated in the Pseudomonas aeruginosa infection group (n=6) and four patients of this group died during the last two years. On the other hand, the concentration of alpha-1 antitrypsin (alpha-1 AT) in BALF from the patients showing elastase activity increased approximately 8-fold when compared to the nonsmoker group.
We emphasize that neutrophil elastase is the most important proteinase which injures lung tissues and that a chronic respiratory tract infection, especially Pseudomonas aeruginosa infection, is a major factor for migration of neutrophils into lung tissues.
