CCL26 (eotaxin-3) is a CC chemokine that functions as a potent chemoattractant for eosinophils and basophils through signaling via the CCR3 receptor 12. The protein induces transient calcium mobilization in CCR3-expressing cells and promotes eosinophil chemotaxis both in vitro and in vivo 1. CCL26 also acts as a ligand for the CX3CR1 receptor, triggering cell migration. The gene is constitutively expressed in heart and ovary, and its expression is upregulated in vascular endothelial cells by IL-4 and IL-13 1. CCL26 expression is significantly elevated in type 2 inflammatory diseases including atopic dermatitis, asthma, and eosinophilic esophagitis, where it contributes to eosinophil accumulation at sites of inflammation 1. In atopic dermatitis specifically, dupilumab—an IL-4 receptor antagonist—substantially reduces CCL26 expression as part of its therapeutic mechanism 34. CCL26 serves as a biomarker of type 2 inflammation and a potential therapeutic target in allergic and atopic diseases through CCR3 antagonism or upstream IL-4/IL-13 inhibition.