Interleukin-31 (IL-31) is a protein that in humans is encoded by the IL31 gene that resides on chromosome 12. IL-31 is an inflammatory cytokine that helps trigger cell-mediated immunity against pathogens. It has also been identified as a major player in a number of chronic inflammatory diseases, including atopic dermatitis.
IL-31 is produced by a variety of cells, namely type 2 helper (TH2) T-cells. IL-31 sends signals through a receptor complex made of IL-31RA and oncostatin M receptor β (OSMRβ) expressed in immune and epithelial cells. These signals activate three pathways: ERK1/2 MAP kinase, PI3K/AKT, and JAK1/2 signaling pathways.