Psoriasis is a chronic inflammatory skin disorder effectively treated by blocking IL-17RA, a receptor chain used by several IL-17 family members, including IL-17E. Although IL-17A is critically involved in the pathogenesis of psoriasis, the contribution of IL-17E remains unknown. Here we show that IL-17E+ cells are more abundant than IL-17A+ cells in lesional psoriatic skin. IL-17E synthesis is increased in keratinocytes within psoriatic plaques, and macrophages having a mixed M1/M2 phenotype represent an important proportion of the IL-17E+ cells infiltrating the dermis.
