Defining the landscape of human epidermal mononuclear phagocytes

This Letter addresses the accurate definition and unification of mononuclear phagocyte subsets within the stratified squamous epithelium of the skin and type II mucosal tissues. While Langerhans cells were long thought to be the sole mononuclear phagocyte resident in these tissues, recent high-parameter technologies have uncovered that a dendritic cell that expresses CD1a and CD207 is also present. Here, we reconcile previous studies to unify the literature on dendritic cells within human epidermis and how they fit into our current understanding of mononuclear phagocyte subsets.