TNF and psoriasis: Psoriasis is closely related to T‐cell immunity, and elevated levels of cytokines such as IL‐17A and TNF‐α can be detected in skin lesions and serum, in which the T‐cell‐mediated immune response significantly contribute to the onset and progression of psoriasis, with IL‐23 and Th17 cells playing essential roles in the occurrence and maintenance of psoriasis.16, 17