Interleukin-23: a key cytokine in inflammatory diseases

Ann Med. 2011 Nov;43(7):503-11. doi: 10.3109/07853890.2011.577093. Epub 2011 May 17.


Interleukin-23 (IL-23) is a pro-inflammatory cytokine composed of two subunits, p19 and p40. The p40 subunit is shared with IL-12. IL-23 and IL-12 have different receptors and different effects. Whereas IL-12 induces development of Th1 cells, which produce interferon-γ, IL-23 is involved in differentiation of Th17 cells in a pro-inflammatory context and especially in the presence of TGF-β and IL-6. Activated Th17 cells produce IL-17A, IL-17F, IL-6, IL-22, TNF-α, and GM-CSF. Inflammatory macrophages express IL-23R and are activated by IL-23 to produce IL-1, TNF-α, and IL-23 itself. These effects identify IL-23 as a central cytokine in autoimmunity and a highly promising treatment target for inflammatory diseases. IL-23 is found in the skin of patients with psoriasis, in the bowel wall of patients with chronic inflammatory bowel disease, and in synovial membrane of patients with rheumatoid arthritis. IL-23 is involved in osteoclastogenesis, independently from IL-17, via induction of RANKL expression. Debate continues to surround the role for IL-23 in the pathophysiology of inflammatory joint diseases (rheumatoid arthritis and spondyloarthritis). Ustekinumab, which inhibits IL-12 and IL-23 by blocking p40, has been found effective in cutaneous psoriasis and psoriatic arthritis, as well as in Crohn's disease. Treatments that specifically target IL-23 (antibodies to p19) are being developed.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Drug Delivery Systems*
  • Drug Design
  • Humans
  • Inflammation / drug therapy
  • Inflammation / immunology
  • Inflammation / physiopathology*
  • Interleukin-12 / immunology
  • Interleukin-12 / metabolism
  • Interleukin-12 Subunit p40 / immunology
  • Interleukin-12 Subunit p40 / metabolism
  • Interleukin-23 / immunology
  • Interleukin-23 / metabolism*
  • Interleukin-23 Subunit p19 / immunology
  • Interleukin-23 Subunit p19 / metabolism
  • Macrophages / immunology
  • Macrophages / metabolism


  • Interleukin-12 Subunit p40
  • Interleukin-23
  • Interleukin-23 Subunit p19
  • Interleukin-12