TLR4 and psoriasis: In the present study, we detected the serum levels of HMGB1‐TLR4‐IL‐23‐IL‐17A pathway in psoriasis patients, carried out in vitro experiments to explore the regulatory effects of HMGB1 on Th17 cell differentiation and IL‐17A expression, and tried to provide new ideas for the immune targeted therapy of psoriasis.