Neutrophil chemotaxis in bronchiectasis: a study of peripheral cells and lung secretions.

1. Some bronchiectatic patients persistently expectorate purulent secretions containing many polymorphonuclear leucocytes (PMN) and bacteria, suggesting ineffective microbial clearing from the lung. We have therefore studied several aspects of PMN recruitment to the lung by chemotaxis. 2. Circulating PMN from patients with bronchiectasis show a variable chemotactic response to the synthetic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine. This is similar to the response of PMN from healthy controls and suggests that failure to clear microbial organisms is not due to defective chemotaxis as measured here. 3. Purulent sputum solphase demonstrates chemotactic activity against control PMN. This activity is greater (P less than 0.001) than that found with mucoid sputum solphase, which is consistent with the neutrophil content of the secretions in vivo. 4. Successful antibiotic therapy reduces the chemotactic activity of purulent sputum solphase from a median value of 183 (range 28-201) cells/high power field to 33.5 (range 0.7-64) cells/high power field (P less than 0.0025). This indicates that the chemotactic activity is largely associated with bacterial load.