Pathophysiology of chemokines and chemokine receptors in dermatological science: A focus on psoriasis and cutaneous T-cell lymphoma

Skin is an immunological organ with a delicate immunological network that governs the homeostasis and homing of the pro- and anti-inflammatory immune cells. Dysregulated immune response may result in psoriasis, a common inflammatory skin disease. Inappropriate immune surveillance, on the other hand, may cause the development of cutaneous lymphomas. Such homing of the immune cells likely depends on the interactions of chemokine and its receptors. Chemokine receptors and their corresponding chemokine ligands play key roles in the migration and localization of normal T cells in psoriasis and neoplastic T cells in cutaneous T-cell lymphoma (CTCL). While important in immune cell homing in psoriatic skin, chemokines and chemokine receptors may also be used for arrest, homing, and survival of neoplastic T cells in CTCL. In this review, we discuss roles of chemokine receptors, including those of CCR4 and CCR10 in the pathogenesis of CTCL, and of CCR6 in the pathogenesis of psoriasis. Targeting chemokines and chemokine receptors may lead to more effective treatments in these two skin diseases.