CCR3 and asthma: To understand whether the enhanced eosinophil activation in EA was due to the upregulation of the chemokine receptors in these eosinophils, we compared the expression levels of IL-5 receptor (including subunits IL5RA and CSF2RB), CCR3 and DP2 in eosinophils from different asthma conditions at protein level using flow cytometry (Fig. 3A and Supplementary Fig. 4A).