The interrelationship of sputum inflammatory markers in patients with chronic bronchitis

Many of the features of bronchial disease are believed to be caused by dama ge to the airways by elastase released by recruited neutrophils. There have been few studies of the mechanisms involved and the interrelationships bet ween components of the inflammatory process. We studied secretions from pat ients with chronic bronchitis in the stable state. We assessed the presence of neutrophils by measuring myeloperoxidase (MPO) activity and active neut rophil elastase (NE). These results were compared with the chemoattractants interleukin-8 (IL-8) and leukotriene B-4 (LTB4), the bronchial inhibitor s ecretory leukoprotease inhibitor (SLPI), and protein leak (sputum/serum alb umin ratio). MPO correlated with NE activity (r = 0.68, p < 0.001) and both IL-8 (r = 0.52, p < 0.001) and LTB4 (r = 0.41, p < 0.001) indicating an as sociation with the chemoattractants. Elastase activity correlated with IL-8 (r = 0.55, p < 0.001) and LTB4 (r = 0.41, p < 0.001) but negatively with S LPI (r = -0.49, p < 0.001). NE also correlated positively with protein leak (r = 0.36, p < 0.001), suggesting a cause and effect. MPO and protein leak correlated negatively with FEV1 (percentage of predicted) only in patients with chronic obstructive pulmonary disease (COPD) without alpha(1)-antitry psin deficiency (r = -0.37, p < 0.001; r = -0.42, p < 0.01, respectively). These complex interactions provide a template for future studies with speci fic inhibitors or agonists which will clarify the role of individual factor s.