CCL17 and allergic disease: The activated mast cells are sensitized to release allergic mediators such as granular contents (β-hexosaminidase) as well as allergic cytokines (interleukin (IL)-4, IL-5, IL-6, IL-13), and tumor necrosis factor (TNF)(-α) and the chemokine, thymus activation-regulated chemokine (TARC), which induces allergic disease [6,7].