Plasma levels of leukotriene E4 during clinical course of bronchial asthma and the effect of oral prednisolone.

To investigate the relationship between circulating leukotriene E4 and bronchial asthma, we tried to measure the concentration of leukotriene E4 during the clinical course of bronchial asthma with or without oral prednisolone treatment. Additionally, we investigated the relationship between the LTE4 levels and FEV1 (percent predicted) and PaCO2 (mm Hg) concomitantly. Two milliliters of blood were drawn from the femoral artery of eight patients on three occasions: (1) during remission; (2) during an attack treated without prednisolone; and (3) during an attack treated with prednisolone. Leukotriene E4 was detected by high-pressure liquid chromatography and radioimmunoassay. In eight asthmatic patients, mean (SD) leukotriene E4 levels on the three occasions were 11.8 (2.61), 48.4 (18.2), and 32.6 (8.28) pg/ml, respectively. In contrast, the mean leukotriene E4 level of ten normal control subjects was 11.8 (4.49) pg/ml. Leukotriene E4 levels differed significantly between remission and attack treated without prednisolone, and between attacks treated with and without prednisolone. Mean FEV1 values were 85.5 (3.07), 50.5 (9.58), and 65.9 (7.44) on the three occasions, respectively; corresponding mean PaCO2 values were 31.7 (2.74), 55.5 (5.81), 48.9 (2.56), respectively. Leukotriene E4 was significantly correlated with FEV1 and relatively with PaCO2 during an attack without prednisolone. We suggest that leukotriene E4 levels in arterial blood reflect the severity of asthmatic attacks and orally administered prednisolone may affect the leukotriene E4 levels.