Abstract:Psoriasis is a chronic inflammatory disease accompanied by keratinocyte hyperproliferation and leukocyte infiltration. Although it is known that cytokines such as IL-17 and TNF-α from T cells are strongly linked with psoriasis, how keratinocytes affect the differentiation and expansion of T cells and induce a positive feedforward mechanism to amplify local inflammatory responses is not fully understood. Accumulating evidence demonstrates that IL-23/IL-17/IL-22 axis plays a crucial role in leukocyte recruitment and epidermal hyperproliferation. In these studies keratinocytes are thought to act as the readout in the pathogenesis of psoriasis,while the influence of keratinocytes on T cell differentiation and expansion and the important role of crosstalk among keratinocytes, dendritic cells and T cells in the pathogenesis of psoriasis are neglected. Here we summarize how keratinocytes and T cells play roles in the pathogenesis of psoriasis, especially how keratinocytes, dendritic cells and T cells form a network to control the development of psoriasis, and provide new insights into the treatment of psoriasis.