CCL17 is a C-C chemokine that functions primarily as a Th2-selective T-cell chemoattractant, binding to CCR4 on T-cell surfaces to mediate chemotactic activity 123. Beyond T-cell recruitment, CCL17 plays broader roles in inflammation and immune regulation. It is produced by alternatively activated (M2) macrophages 4, dendritic cells 5, and multiple stromal cells including keratinocytes and fibroblasts 6. CCL17 mediates GM-CSF-driven pain and inflammation 7 and contributes to wound healing through fibroblast migration. In disease contexts, CCL17 elevation associates with type 2 inflammatory conditions. Elevated CCL17 marks disease activity in atopic dermatitis and bullous pemphigoid, where it amplifies Th2-mediated immune responses 65. In myocardial injury, CCL17 from CCR2+ macrophages and dendritic cells exerts pathogenic effects by suppressing regulatory T-cell recruitment through biased CCR4 signaling, promoting adverse cardiac remodeling 8. In pituitary adenoma, lactate-induced M2 macrophage polarization drives CCL17 secretion, promoting tumor invasion via the CCL17/CCR4/mTORC1 axis, with high CCL17 correlating with increased invasion and recurrence 9. CCL17 also participates in obesity-associated vascular dysfunction through CCR4-mediated endothelial inflammation 10. These findings establish CCL17 as a multifaceted inflammatory mediator with therapeutic potential as both a biomarker and intervention target 1112.