Mediator release from basophil granulocytes in chronic myelogenous leukemia.

Mediator release from the leukocytes of two patients with chronic myelogenous leukemia and basophilia was studied using rabbit antihuman IgE antibody. The release of histamine, slow reacting substance of anaphylaxis (SRS-A), platelet activating factor (PAF), chemotactic activity for neutrophils and eosinophils, and an inhibitor of eosinophil migration was observed. However, the release of SRS-A from the basophils of one patient and the release of chemotactic activity from both patients displayed unusual properties. During acceleration of the disease process, the basophils of one patient released maximal SRS-A activity at progressively lower concentrations of anti-IgE. Both patients released a high molecular weight factor (M.W. greater than 20,000) which enhanced the migration of neutrophils and eosinophils and a low molecular weight chemotactic factor (M.W. less than 500) which selectively attracted eosinophils. A double peak of eosinophil chemotactic activity was routinely observed for the low molecular weight factor; this was shown to represent the eosinophil chemotactic activity of histamine with relative inhibition of migration at the histamine peak. There was little release of the tetrapeptides, ECF-A, in these patients which facilitated demonstration of this eosinophilotactic activity of histamine. These results suggest that the eosinophil chemotactic activity observed in acute allergic reactions is the net effect of the release of multiple chemotactic factors.