IL17A and psoriasis: Psoriasis is a commonly seen, chronic and inflammatory dermatosis, which is characterized by immune cell infiltration in the dermis and epidermis and excessive proliferation and abnormal differentiation of keratinocytes.46 As Th17 and Th22 secreted cytokines, IL‐17 and IL‐22 induce keratinocyte immune activation and hyperplasia.47 In our present study, as expectedly, both IL‐17 and IL‐22 levels were increased in psoriasis lesions in patients and IMQ mouse models.