Optimizing of the basophil activation test: Comparison of different basophil identification markers

Background Flowcytometric identification of basophils is a prerequisite for measuring activation of basophils with IgE‐dependent or IgE‐independent stimuli. Aim of this study was to compare different marker combinations in a simultaneous multicolor flowcytometric measurement. Methods Ten patients with a grass pollen allergy and three controls were included in the study. Basophilic cells were gated by using anti‐CCR3, anti‐IgE, anti‐CRTH2, anti‐CD203c, and anti‐CD3. Cells were activated by a monoclonal anti‐FcεRI antibody, N ‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP), and the allergen extract Phleum pratense . The activation marker anti‐CD63 was used. Results The highest relative number of basophils was found with anti‐CCR3 + cells, anti‐IgE + and anti‐IgE + /anti‐CD203c + cells, the lowest with CRTH2 + /CD203c + /CD3 − cells. A very good and good concordance of CCR3 + cells was seen with CCR3 + /CD3 − cells and CRTH2 + /CD203c + /CD3 − cells in all experiments. The contamination of the CCR3 + population with CD3 + cells and the contamination of the IgE + ‐population with CCR3 − cells and CD203 − cells were the lowest compared to all other marker combinations. Conclusions As the highest relative number of basophils was identified by anti‐CCR3 followed by the anti‐IgE and anti‐IgE/antiCD203c positive population in most cases, these markers can generally be recommended for identification of basophils. If a basophil population with very high purity is needed, anti‐IgE should be chosen. © 2014 International Clinical Cytometry Society