Airway Levels of Mast Cell—derived Mediators in Exercise-induced Asthma

In order to assess the role of mast cell—derived mediators in the pathogenesis of exercise-induced asthma (EIA), we completed pre- and postexercise bronchoalveolar lavage (BAL) in seven atopic subjects with EIA. The study subjects were defined as having EIA if they exhibited a greater than 15% decrease in FEV1 after completing 6 min of treadmill exercise. There were no significant differences between mean preexercise and mean postexercise mast cell—derived BAL histamine (186 ± 67 versus 148 ± 36 pg/ml), tryptase (4.5 ± 2.0 versus 2.8 ± 2.0 ng/ml), prostaglandin D2 (26 ± 11 versus 32 ± 25 pg/ml), or leukotriene C4 (< 100 versus < 100 pg/ml). In addition, mast cells present in BAL fluid after exercise contained similar amounts of cellular histamine compared with BAL mast cells obtained before exercise (preexercise BAL cellular histamine, 26.6 ± 12.3 ng/106 BAL cells; postexercise BAL cellular histamine, 22.7 ± 9.1 ng/106 BAL cells), indicating that depletion of preformed mast cell mediators are unlikely to ...