Immune surveillance in the skin: mechanisms and clinical consequences.

The skin, as the primary interface between the body and the environment, provides the first line of defence against a broad array of microbial pathogens and trauma. In addition to its properties as a physical barrier, the skin has many active defence mechanisms. In this review, we discuss the interaction between the innate and adaptive immune systems in the skin as a model for immune function at epithelial-cell interfaces with the environment. How these mechanisms account for the robust nature of cutaneous immune surveillance and how their dysregulation drives the pathogenesis of inflammatory skin disorders and skin-based tumours are the subjects of this review.