Abstract
The sulphidopeptide leukotriene C4 and D4 (LTC4, LTD4) are potent bronchoconstrictors. To investigate the role of LTs in allergic asthma, time related changes in urinary LTE4, a stable urinary end-product of LTC4 and LTD4, was evaluated after BPT with HD in 29 patients with bronchial asthma whose skin tests and radioallergosorbent test (RAST) were positive. The following results were obtained: 1) The levels of urinary LTE4 did not change in 12 hours in patients who had no response to BPT with HD. 2) The levels of urinary LTE4 increased significantly (p<0.01) 3 hours after inhalation by patients who had immediate single asthmatic responses (IAR) . 3) The levels of urinary LTE4 increased significantly (p<0.01) 3 hours after inhalation by patients who had dual asthmatic responses (DAR) . However, there were no significant changes from 3 to 12 hours. 4) The levels of urinary LTE4, measured during the first 3 hours after inhalation were not correlated with the maximal decreases in FEV1.0, PER, V50, or V25 in 0 to 3 hours after inhalation. These results suggest that the LTE4 precursors, LTC4 and LTD4, are important bronchoconstrictive mediators that cause IAR after allergen inhalation.
