Inflammation--role of the neutrophil and the eosinophil.

Neutrophils are regularly identified in the airway secretions of patients with smoking-related chronic bronchitis and in those with chronic obstructive pulmonary disease. The migration and activation of these cells plays a role that is central to the secondary bronchial defences against potential bacterial pathogens. Where these processes persist or are excessive, potent mediators derived from the neutrophil may cause a perpetuation of bronchial inflammation and result in bronchial epithelial damage and impairment of endobronchial defences. Recent evidence has suggested that the eosinophil may also be present in the airways of some patients with chronic bronchitis, although its role in bronchial inflammation is not yet clear. In this article we have reviewed the evidence relating to the roles of both the neutrophil and of the eosinophil in the airway inflammation of chronic bronchitis.