CCL17 and vitiligo: Animal experiments on vitiligo mice have shown that upregulating the mouse chemokine CCL22 to activate the mouse Treg cells could increase the abundance of Tregs in the skin and improve the skin lesions of vitiligo.15, 16 However, no studies have reported the function of another CCR4 ligand CCL17 in regulating CD8+ T cells homing to skin in vitiligo.