These activated dendritic cells release inflammatory cytokines, such as TNF-α, IFN-γ, and interleukin-17 (IL-17), and in return, these cytokines promote keratinocyte proliferation and psoriasis progression [138,139,140,141] with the involvement of the TLR4/NF-κB signaling pathway [142,143]. The gene discussed is IL17A; the disease is psoriasis.