Urinary leukotriene E4 levels after allergen and exercise challenge in bronchial asthma.

Urinary leukotriene E4 (LTE4) concentrations were measured in six asthmatic subjects after treadmill exercise, and in five asthmatic subjects after allergen challenge. Exercise and allergen challenge produced a 42 +/- 18% (mean +/- SD) and 22 +/- 8% fall in FEV1, respectively. The baseline concentration of urinary LTE4 in subjects challenged with exercise was 64 (27 to 150) pg/mg creatinine (geometric mean and 95% confidence interval), and in those challenged with allergen it was 36 (23 to 59) pg/mg creatinine. Urinary LTE4 concentrations did not change significantly in the 24 h after exercise. In contrast, there was a mean 4-fold increase in urinary LTE4 during the 3 h after allergen challenge.