Increased generation of leukotriene C4 from eosinophils in asthmatic patients.

Human eosinophils with a density of over 1.095 were isolated from peripheral blood by dextran sedimentation, centrifugation with Lymphoprep and density gradients with Percoll. After the cells (1 X 10(5)/ml) were incubated with 1 microgram/ml calcium ionophore A23187 for 20 min, leukotriene C4 (LTC4) content in the supernatant was measured by radioimmunoassay. The generation of LTC4 was significantly higher in the cells from extrinsic asthmatics (23.5 +/- 14.8 ng/10(6) cells, mean +/- SD, n = 26, P less than 0.01) and intrinsic asthmatics (24.6 +/- 20.6 ng/10(6) cells, n = 27, P less than 0.01 as compared with normal healthy subjects (8.3 +/- 7.7 ng/10(6) cells, n = 10). There was no significant difference in the generation of LTC4 between intrinsic and extrinsic asthmatics. These observations indicate that eosinophils from asthmatic patients have increased ability to release LTC4.