Neutrophil inflammation and activation in bronchiectasis: Comparison with pneumonia and idiopathic pulmonary fibrosis

Background: Pulmonary inflammation in bronchiectasis, pneumonia and idiopat hic pulmonary fibrosis (IPF) is dominated by neutrophils. Pathophysiologic differences are seen in the degree of airway and tissue destruction. Neutro phil activation and neutrophil proteolytic activity might differ between br onchiectasis, pneumonia and IPF. Objective: The aim of this study was to de termine whether levels of inflammatory and protective markers in bronchoalv eolar lavage (BAL) differed among cases of bronchiectasis, pneumonia and IP F. Methods: We studied 11 bronchiectasis patients (group 1), 30 pneumonia p atients (group 2), 15 IPF patients (group 3) and 12 healthy volunteers (gro up 4). In the bronchoalveolar lavage fluid, concentrations of alpha(1)-prot einase inhibitor, myeloperoxidase (MPO) and elastase-alpha(1)PI complex wer e determined using immunoluminometric assays. Elastase inhibition capacity (EIC) and elastase activity were determined using a colorimetric assay. Res ults: No EIC, but free elastase activity, was found in 82% of group 1, 20% of group 2, 20% of group 3 and 0% of group 4. Median MPO concentration was highest in group 1: 7,951 ng/ml (16th-84th percentile [16-84%]: 256-36,342) vs. 692 ng/ml (106-2,279; group 2), 332 ng/ml (98-1,657; group 3), and 0.1 2 ng/ml (0.08-0.26; group 4). Bronchiectasis patients with bronchial Pseudo monas infection showed higher amounts of neutrophils (p < 0.01) and higher elastase activity (p < 0.05) than patients with sterile ravage. Conclusion: Bronchiectasis patients show a severe imbalance between neutrophil activit y and protective molecules leading to possible lung destruction. Chronic Ps eudomonas infection might trigger neutrophil activation. Future research an d treatment strategies should focus on increased bacterial clearance and in hibition of neutrophil toxicity. Copyright (C) 2000 S. Karger AG, Basel.