The pathogenic T cells in psoriasis comprise Th1, Th22, and Th17 cells, along with pathogenic pro-inflammatory cytokines IL-17, IL-22, IFN-γ, TNF-α, IL-12, IL-1, and IL-23 (Grän et al., 2020[61]; Lowes et al., 2014[121]). This evidence concerns the gene IL17A and psoriasis.