Chemokine (C-C motif) ligand 27 (CCL27), also known as cutaneous T-cell-attracting chemokine (CTACK), is a small cytokine belonging to the CC chemokine family. Its gene is located on human chromosome 9. CCL27 is expressed in numerous tissues, including gonads, thymus, placenta and skin. In vitro expression can be induced beyond constitutive levels by stimulation with IL-1β or TNF-α, while gluticosteroids can suppress it. CCL27 elicits its chemotactic effects by binding to the chemokine receptor CCR10. It is associated with homing of memory T lymphocytes to the skin, and plays a role in T cell-mediated inflammation of the skin. In healthy mice, lymphocytes accumulate at sites of CCL27 injection. In a mouse contact-hypersensitivity model, lymphocyte recruitment is impaired by administration of anti-CCL27 neutralizing antibodies.