Inflammatory activity in sputum chronic bronchitis and bronchiectasis during clinical stablity

Neutrophil elastase has been implicated in the pathogenesis of both chronic bronchitis (CB) and bronchlectasis (BE). However these diseases differ in the intensity of neutrophil infiltration found in bronchial secretions and this may influence the pathophysiology of the two conditions. For example in the stable clinical state elastase activity is usually only found in BE. In order to characterise these differences further we have compared inflammatory activity in the two diseases in the stable clinical state by collecting sputum from 7 patients with CB and 14 patients with BE. Sol-phase was obtained and neutrophil content was assessed by the measurement of myeloperoxidase (MPO) by chromogenic assay. The chemokines interleukin-8 (IL-8) and leukotriene B4 (LTB4), and the proteinase inhibitors alpha 1 proteinase inhibitor (α-1-PI) and secretory leukoprotease inhibitor (SLPI) were measured by ELISA. Finally neutrophil elastase (NE) and cathepsin B (Cat B), (which is activated in the lung by NE), were measured by chromogenic assay. Mean results are summarised in the table. MPO units Elastase μM Cat B U/ml IL-8 nM LTB4 nM αlPI μM SLPI μM BE mean (SE) 31.48 1.7 1.49 23.4 25.2 2.02 1.13 (6.98) (0.65) (0.27) (4.4) (5.93) 00.83) (0.36) CB mean (SE) 0.28 0 0 6.05 11.34 0.69 2.92 (0.03) (1.17) (3.51) (0.24) (0.52) Values for patients with BE were significantly higher for all factors measured (range p < 0.001 to p < 0.05). The results indicate that BE is associated with a greater degree of inflammation than CB. During clinical stability elastase and cathepsin B activity are only a feature of patients with BE and may be related to greater bronchial damage in these subjects. The lower concentration of SLPI in BE may reflect the presence of elastase activity.