Both adaptive and innate immune cells have essential role in pathogenesis of psoriasis, especially keratinocyte, dendritic cell, and T cell.[38] Many abnormalities occur in psoriasis development, involving antigen presentation, activation of the NF-κB signaling pathway, differentiation of T helper cell populations, particularly Th17 cells, and increased IL-17 responses. Here, IL17A is linked to psoriasis.