[The keratinocyte--a biologically active cell].

Both keratin synthesis and the formation of the horny layer are "classical" functions of human epidermal keratinocytes. In recent year a couple of interesting immunological functions of keratinocytes have been discovered. In the present review phagocytosis, production and secretion of cytokines (IL-1, IL-3, IL-6, IL-8, CSF, ECDF, IFN) and their ligands as well as the expression of selected cell surface receptors (HLA-DR, ICAM-1, Fc-gamma receptor) ligands are described.