CCL22 was described initially as a constitutively produced, thymus-specific chemokine, implicated in the recruitment of T cells. One of the functions of CCL22 originally described was induction of migration of CCR4+ Th2 cells, but it has additionally been shown to regulate migration of Tregs. CCL22 has been implicated in a number of diseases, including allergen-induced lung inflammation, atopic dermatitis, and lymphoma. Similarly, a presumed role for CCR4+ cells has been suggested for endotoxic shock, rheumatoid arthritis, T cell lymphoma, and autoimmune diabetes