Dermal γδ T cells--a new player in the pathogenesis of psoriasis.

Psoriasis is considered as a T-cell driven chronic inflammatory skin disease. Both T helper (Th) 1 and Th17 cells have been demonstrated to participate in psoriasis pathogenesis. Recently, a new subset of γδ T cells residing in the dermis has been identified. Dermal γδ T cells are the major source of interleukin (IL)-17 in the skin upon IL-23 stimulation. More importantly, they are also shown to be involved in psoriasis development. In this review, we focus on this newly discovered cell population both in mice and human, particularly discussing its role in the pathogenesis of psoriasis. The biologic therapeutics targeting dermal γδ T cell and its related molecules in the treatment of psoriasis are also included.