Interleukin 36 beta (IL-36β, IL-1F8) is a member of the IL-1 family of cytokines. The inflammatory activity of IL-36β occurs through indirect activation of the NF-kappaB and MAPK pathways. This activation occurs via the intermediary Interleukin-1 receptor and accessory proteins (IL-1Rrp2 and IL-1RAcP, respectively). IL-36α, IL-36β, and IL-36γ are associated with the immune system in the skin. These cytokines directly activate keratinocytes and antigenpresenting cells and indirectly activate T cells to cause psoriasis. In primary human joint cells (synovial fibroblasts and articular chondrocytes) IL-36β exerts proinflammatory effects, but serum levels of IL-36β do not correlate with joint inflammation.