Multiple animal models have been developed to study psoriasis and its mechanisms (spontaneous, xenograft, genetically engineered, intradermal injection of cytokines (L-23 or IL-17), and topical application of irritant imiquimod (IMQ)) resulting in skin inflammation, hyperproliferation of keratinocytes, and immune cell infiltration, mimicking key aspects of human psoriasis (240). Here, IL17A is linked to psoriasis.