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Updated: Jul 18, 2026
Basophil Activation Test for Investigation of IgE-Mediated Mechanisms in Drug Hypersensitivity
Published on: September 16, 2011
Flow cytometric basophil activation tests: Staining of exteriorized basophil granule matrix by fluorescent avidin
Didier G Ebo1,2, Jessy Elst1, Michel van Houdt1
1Department of Immunology, Allergology, Rheumatology and the Infla-Med Research Consortium of Excellence, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium.
Background:
Staining of exteriorized basophil granule matrix by fluorescent avidin might be a reliable technique to monitor basophil degranulation. This study compares the avidin-based technique with the upregulation of CD203c and appearance of CD63 in response to various stimuli.
Methods:
Fourteen individuals responsive to anti-IgE, nine healthy controls, and five birch pollen-allergic patients, and five nonresponders were studied. Activation experiments included anti-IgE, fMLP, interleukin-(IL)-3, and birch pollen allergen. Basophil activation/degranulation was analyzed by flow cytometry and microscopy using anti-CD63, anti-CD203c, and avidin.
Results:
Stimulation with anti-IgE, fMLP, and relevant allergen results in upregulation of CD203c, CD63 appearance, and an increase in avidin binding. In response to anti-IgE and allergen, upregulation of CD203c peaks within 10 min, CD63 and avidin binding reach a plateau after 10-20 min. CD63 staining leads to a bimodal distribution, avidin staining causes a unimodal shift with a less clear discrimination between degranulating and nondegranulating cells. In response to fMLP, upregulation of CD203c and CD63 and avidin binding are maximal after 2.5 min. Following incubation with anti-IgE and fMLP, percentages of CD203c+ cells are higher than those of CD63+ and avidin+ cells, pointing to a dissociation between activation and degranulation. Percentages of CD63+ cells are systemically higher than those of avidin+ cells. Incubated with IL-3 only upregulates CD203c, while no CD63 or avidin binding is observed.
Conclusions:
Staining of exteriorized proteoglycans by avidin is a reliable technique to quantify basophil degranulation but offers no added value when compared to traditional assays that use CD63 as a readout.
