Basophil histamine release by platelet-activating factor in aspirin-sensitive subjects with asthma.

Histamine release induced by platelet-activating factor (PAF) from leukocytes of aspirin-sensitive subjects with asthma was higher than that from normal control subjects, despite the similarity of anti-IgE-induced histamine release. Moreover, basophils of some aspirin-sensitive subjects with asthma released histamine by PAF stimulation in the absence of cytochalasin B that affects histamine release and is required in PAF-induced histamine release from leukocytes of atopic subjects with asthma and normal control subjects. In addition to temperature dependency and inhibition by ethylenediaminetetraacetic acid reported previously, PAF-induced histamine release was enhanced by cytochalasin B and indomethacin and inhibited by dexamethasone. These features are common with IgE-mediated histamine release and suggest the existence of the common pathway to PAF-induced histamine release and IgE-mediated histamine release. The results in the present study indicate the pathophysiologic significance of PAF-induced histamine release and that activation of basophils by PAF may be relevant to the pathogenesis in some aspirin-sensitive subjects with asthma.