Neutrophil chemotactic activity is increased in nasal secretions of long-distance runners.

For years physicians have observed a high incidence of infections after strenuous exercise. Recent observations suggest an increase of neutrophils in the upper airways following a long-distance race. In order to elucidate mechanisms responsible for the influx of neutrophils in airway mucosa, we tested neutrophil chemotactic activity (NCA) in nasal lavages of amateur runners. Thirty-six amateur runners entered in a marathon race (42.2 km) and 24 healthy sedentary subjects participated in the study. Nasal lavages (NAL) were performed several times before and after the race. The total number of recovered neutrophils was measured and the NCA was determined using a modified Boyden chamber. The number of PMNs in NAL of the runners immediately after the race was increased 2.7-fold (p < 0.01) compared to the values obtained on the same day prior to the race (128 +/- 19 vs. 48 +/- 16, x 10(3)), remained elevated several days after the race and returned to baseline after 1 week. The race resulted also in a 2.5-fold (p < 0.01) increase of NCA immediately after the competition compared to the pre-race values of the same day (78 +/- 5.2 cells/8 High Power Fields, HPF vs. 31 +/- 3.4 cells/8 HPF). The findings suggest that NCA might play an important role in attracting neutrophils to the airways. The nature and origin of NCA in airway secretions is presently not known.