 Cytokines released from DCs stimulate dying keratinocytes to secrete TNF-alpha, IL-1 and IL-6 leading to the chemotaxis of T cells, natural killer cells and monocytes to the epidermis.These cells release IL-23 which induce Th17 cells to produce IL-17.IL-17 interaction with IL-17RA receptors, abundant on the keratinocyte cell surface, incite epidermal cells to increase expression of IL-6, antimicrobial peptides, IL-8 and CCL20.