In vitro bimodal activation of basophil granulocytes in dogs with atopic dermatitis

Peripheral blood leukocytes from 15 dogs with atopic dermatitis, sensitive to Dermatophagoides farinae house dust mites, were incubated with serial dilutions of the sensitizing allergen. Basophil activation, manifested by loss of affinity for specific dies was dose dependent. This dose-dependent degranulation curve exhibited two peaks of activation. The physiologic reasons for this bimodal curve remain unknown at the present time, but could include: heterogeneity of basophil populations, variations in the saturation of IgE receptors or different isotypes of anaphylactic antibodies.