Increased plasma levels of IL-21 and IL-23 in spondyloarthritis are not associated with clinical and MRI findings

Rheumatol Int. 2012 Feb;32(2):387-93. doi: 10.1007/s00296-010-1655-3. Epub 2010 Nov 30.


We have investigated the role of the Th17-related cytokines interleukin-17A (IL-17A), IL-21, and IL-23 in spondyloarthritis (SpA) by examining their association with disease activity and magnetic resonance imaging (MRI) findings in patients with SpA (n = 80). Furthermore, to investigate the cellular origins of the cytokines, paired mononuclear cells from blood and synovial fluid were examined for the expression of IL-17A, IL-21, and IL-23R using multicolor flow cytometry. Both IL-21 and IL-23 levels were increased in plasma from SpA patients compared with healthy volunteers (P < 0.05), whereas IL-17A was not. A significant correlation was observed between individual levels of IL-21 and IL-23 (r = 0.7, P < 0.001). No association between individual levels of IL-17A, IL-21, and IL-23 with C-reactive protein (CRP), MRI changes, and clinical scoring (BASMI, BASFI, and BASDAI) were observed. The frequency of CD4+CD45RO+ T cells expressing IL-21 and IL-23R was increased in the inflamed SpA joint compared to peripheral blood (P < 0.05). This study demonstrate that the plasma levels of the Th17-related cytokines IL-21 and IL-23, but not IL-17A, are increased in SpA patients, but we did not find evidence that the level of these cytokines reflect disease activity in SpA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Female
  • Humans
  • Interleukin-17 / biosynthesis
  • Interleukin-17 / blood
  • Interleukin-23 / blood*
  • Interleukins / biosynthesis
  • Interleukins / blood*
  • Magnetic Resonance Imaging / methods
  • Male
  • Middle Aged
  • Spondylitis, Ankylosing / blood*
  • Spondylitis, Ankylosing / immunology
  • Spondylitis, Ankylosing / pathology*
  • Up-Regulation* / immunology


  • IL17A protein, human
  • Interleukin-17
  • Interleukin-23
  • Interleukins
  • interleukin-21