Increasing evidence comfirmed that macrophages are also crucial to psoriasis pathogenesis.[56,57] There are 2 subtypes of macrophages after polarization, which are MI and M2.[58] The former could secret inflammatory factors (e.g., IL-1, IL-17A, and IL-23), and mainly playing a pro-inflammatory role in psoriasis. Here, IL17A is linked to psoriasis.