Serum neutrophil chemotactic activity and exercise induced asthma.

The changes in serum neutrophil chemotactic activity were studied in 16 asthmatics and in 6 healthy, non-atopic controls. Eight asthmatics gave positive response to exercise challenge. The neutrophil chemotactic activity was determined by a method described by Boyden. The specific airway conductance was used as a lung function parameter. There was a significant increase in the serum neutrophil chemotactic activity after exercise challenge in asthmatic subjects. The increase was less in the asthmatic patients with negative response to exercise (20.8 +/- 6.8), than in those with positive, (41.1 +/- 15). There was also a difference in time course: the maximal value was recorded at 15 min in patients with negative response to exercise and at 6 min in patients with positive. The neutrophil chemotactic activity did not alter significantly in healthy non-atopic controls. The clinical significance of the serum neutrophil chemotactic activity in bronchial asthma is discussed.