CCL27, also known as CTACK, is a small cytokine belonging to the CC chemokine family. Members of this family are proteins characterized by two adjacent cysteines. CCL27 is chemotactic for skin-associated memory T lymphocytes. CCL27 may also play a role in mediating homing of lymphocytes to cutaneous sites. CCL27 plays a pivotal role in establishing the inflammatory infiltrate characteristic for common inflammatory skin diseases. Through binding to the chemokine receptor 1 (CCR1), CCL27 mediates inflammation by promoting lymphocyte migration into the skin.