Development of a system for monitoring the production of leukotriene B4, C4, D4 and E4 in whole blood of pediatric asthmatic patients

We have developed a new method using a computerized photodiode-array spectrophotometer (CPAS), to characterize the biosynthesis and the inhibition of leukotriene (LT) B4, C4, D4 and E4 in calcium ionophore (Ca-I)-stimulated whole blood. The results obtained were as follows: 1. The use of CPAS enabled us to identify and measure LTs from 2 ml volume of Ca-I stimulated whole blood as well as to check the purity of LTs, without any use of radioimmunoassay or bioassay. 2. LTC4 produced in whole blood was almost completely converted to LTE4 after 80 min incubation, and at this time both the production of LTE4 and LTB4 reached a plateau and remained constant thereafter. 3. Azelastine added in vitro caused a dose-dependent inhibition of Ca-I stimulated LTB4 and LTE4 production with an IC50 of 10 microM.