Psoriasis is primarily characterized as a Th1-driven disease because the levels of Th1 cytokines, such as IFN-γ, TNF-α, and interleukin (IL)-12, are markedly elevated in psoriatic lesions, while there is no such an increase in expression of Th2 cytokines (IL-4, IL-5, and IL-13) (37–39). Here, TNF is linked to psoriasis.