Together, these findings (a) evidence the prominent role of immune cells, rather than epidermal keratinocytes, in mediating the IL-25-induced recruitment of neutrophils, (b) point to the role of macrophages as an immediate source of IL-25, and (c) support the critical role of this cytokine in psoriasis inflammation, with important implications in regards to psoriasis treatment. Here, IL25 is linked to psoriasis.