Abstract

To evaluate the pathogenetic role of leukotrienes in bronchial asthma, the levels of leukotrienes released from leukocytes stimulated by calcium ionophore A23187 were measured by the HPLC-RIA method in 32 asthmatic patients (12 infectious type, 12 non-hyposensitized atopic type, and 8 hyposensitized atopic type). The following results were obtained: 1) The level of leukotrienes released from the leukocytes of asthmatic patients were higher than those of healthy subjects, but there was no significant difference in the levels of leukotrienes between mild and moderate asthmatic patients. 2) The levels of leukotriene B4 released from the leukocytes of the infectious-type asthmatic patients were higher than those of the atopic asthmatic patients (non-hyposensitized group). There was a tendency for levels of leukotriene C4 released from the leukocytes of the infectious-type asthmatic patients to be higher than those of the atopic-type asthmatic patients. 3) The levels of peptide leukotriene released from the leukocytes of the atopic hyposensitized patients were lower than those of the patients in the atopic non-hyposensitized group, but there were no significant differences in leukotriene B4 between the groups. In addition, the levels of leukotriene C4 released spontaneously from the leukocytes of the hyposensitized group of patients were lower than those in the non-hyposensitized group. 4) Though the mechanism of the efficacy of hyposensitization has not been completely clarified, the reduction of leukocyte ability to release peptide leukotrienes through immunotherapy seems to be part of this mechanism. These results suggest that leukotrienes may play some role in the pathogenesis of both atopic- and infectious-type bronchial asthma.