These T cells and their secreted inflammatory cytokines, such as TNF-α, IL-6, IL-17, and IL-22, interacted with dendritic cells (DCs), keratinocytes (KCs), and vascular endothelial cells and formed the complex network, which plays an essential role in the development of psoriasis (Lowes et al., 2014). This evidence concerns the gene IL17A and psoriasis.