THE CHEMOTACTIC ACTIVITY OF SPUTUM FROM PATIENTS WITH BRONCHIECTASIS

Persistent polymorphonuclear neutrophil (PMN) recruitment to airway is thought to be an important component of continuing inflammation and p rogression of chronic destructive lung diseases. Although chemoattract ants are required for the PMN to migrate, the nature of the chemoattra ctants in. the airways has not yet been clarified. We therefore invest igated the contribution of interleukin-8 (IL-8) and leukotriene-B4 (LT B4) to the chemotactic activity of lung secretions by inhibiting their activity using a monoclonal antibody to IL-8 and an LTB4 receptor ant agonist (LY293111 sodium). Fifty-nine sputum samples obtained from 19 patients with bronchiectasis were studied. In preliminary studies the chemotactic responses to IL-8 and LTB4 were found to be additive, and we were able to remove their contribution independently with the appro priate antibody and antagonist. The chemotactic activity of the secret ions was related to the macroscopic appearance (mucoid, mucopurulent, and purulent), and this appeared to be related to an increase in IL-8 contribution. Chemotactic activity was reduced by antibiotic therapy a nd again that seemed to relate to a reduction in the IL-8 contribution . The contributions of LTB4 were similar among the three types of sput um in varying clinical states. These data suggest that LTB4 and IL-8 a re important chemotactic factors in lung secretions from such patients , although IL-8 appears to play a more important role during acute exa cerbations. These results may be useful in determining therapeutic str ategies for chronic destructive lung diseases in the future.