[The relationship between eosinophils, activated T lymphocyte, leukotreine and the exercise-induced asthma]

To explore the relationship between eosinophils, T lymphocyte, leukotreine (LT) and exercise-induced asthma (EIA).

In 32 asthmatic patients (13 with EIA and 19 asthmatic without EIA) and 8 normal persons, serum eosinophil cationic protein (ECP) and actived T lymphocyte (CD(25)(+)%) in peripheral blood were measured at the time before and 10, 60 minutes after exercise testing. The maximum minute ventilation (V(E)) were also measured. Another 22 non-smoking asthmatic patients with EIA and 10 normal subjects were enrolled for measuring urinary leukotriene E(4) levels before and 2 hours after exercise. EIA patients received zafirlukast 20 mg twice a day for three days. Standardized exercise challenge were performed after 72 hours of medication.

There was a linear relationship between ECP, CD(25)(+)% and the forced expiratory volume in one second (FEV(1)) in asthmatic group (r = -0.79 and -0.61 all P < 0.01). Expressions of IL-4 mRNA, IL-5 mRNA CD(25)(+)% and serum ECP levels showed no significant difference at all testing points between two asthmatic groups, meanwhile, V(E) also showed no difference among three groups. Urinary LTE(4) levels in EIA group increased significantly two hours after exercise. Zafirlukast significantly reduced AUC(0 approximately 60 min) and the percentage of maximum fall in FEV(1) and accelerated the falling FEV(1) to return to pre-exercise baseline.

Hyperventilation during exercise may not be the cause leading to EIA, neither did the activation of T lymphocytes, IL-4 and IL-5 gene expression nor ECP. Leukotriene may play an important role in the pathogenesis of EIA.