Fig. (1) The cells of the skin immune system. The epidermis is made up of keratinocytes with the capacity for some immune function, including cytokine secretion and the potential to act as 'non-professional' antigen presenting cells. The professional antigen presenting Langerhans cells also populate the epidermis, as do lymphocytes. Migrating Langerhans cells can be found in the dermis, along with dermal dendritic cells. Innate cells, such as NK and NKT cells and lymphocytes, populate normal dermis, whereas plasmacytoid dendritic cells are only present in pathological conditions including inflammation. The genital mucosa contains granulocytes, including neutrophils, and macrophages and lymphocytes.