The expression of IL-20 and IL-24 and their shared receptors are increased in rheumatoid arthritis and spondyloarthropathy

Cytokine. 2008 Jan;41(1):16-23. doi: 10.1016/j.cyto.2007.10.004. Epub 2007 Dec 3.


The purpose of this study was to analyze the expression of the two proinflammatory cytokines IL-20 and IL-24 and their shared receptors in rheumatoid arthritis and spondyloarthropathy. IL-20 was increased in plasma of rheumatoid arthritis patients compared with osteoarthritis patients and IL-24 was increased in synovial fluid and plasma of rheumatoid arthritis and spondyloarthropathy patients compared with osteoarthritis patients. IL-20 and IL-24 mRNA was only present at low levels in the synovium. In the synovial membrane, IL-20 protein was present in mononuclear cells and neutrophil granulocytes whereas IL-24 protein was observed in endothelial cells and mononuclear cells. IL-20 receptor type 1 and IL-22 receptor were expressed by granulocytes in the synovial fluid. In synovial fluid mononuclear cell cultures, stimulation with recombinant human IL-20 or recombinant human IL-24 induced monocyte chemoattractant protein 1 (CCL2/MCP-1) secretion, but not tumour necrosis factor alpha mRNA synthesis or IL-6 secretion. Both IL-20 and IL-24 showed correlations to CCL2/MCP-1 in plasma from rheumatoid arthritis and spondyloarthropathy patients. This study associates IL-20 and IL-24 to the synovium of rheumatoid arthritis and spondyloarthropathy and results indicate that the two cytokines contribute to disease pathogenesis through recruitment of neutrophil granulocytes and induction of CCL2/MCP-1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Arthritis, Rheumatoid / metabolism*
  • Arthritis, Rheumatoid / pathology
  • Cells, Cultured
  • Chemokine CCL2 / biosynthesis
  • Endothelial Cells / metabolism
  • Endothelial Cells / pathology
  • Female
  • Humans
  • Interleukins / biosynthesis*
  • Interleukins / pharmacology
  • Leukocytes, Mononuclear / pathology
  • Male
  • Middle Aged
  • Neutrophils / metabolism
  • Neutrophils / pathology
  • Osteoarthritis / metabolism
  • Osteoarthritis / pathology
  • Receptors, Interleukin / biosynthesis*
  • Spondylarthropathies / metabolism*
  • Spondylarthropathies / pathology
  • Synovial Fluid / metabolism*


  • CCL2 protein, human
  • Chemokine CCL2
  • Interleukins
  • Receptors, Interleukin
  • interleukin-20 receptor
  • interleukin-24
  • interleukin 20