Elevated levels of soluble interleukin-1 receptor type II and interleukin-1 receptor antagonist in patients with chronic arthritis: correlations with markers of inflammation and joint destruction

Arthritis Rheum. 1998 Jun;41(6):1083-9. doi: 10.1002/1529-0131(199806)41:6<1083::AID-ART15>3.0.CO;2-9.


Objective: To compare plasma levels of interleukin-1 receptor antagonist (IL-1Ra), soluble IL-1 receptor type I (sIL-1RI), and soluble IL-1 receptor type II (sIL-1RII) in patients with chronic polyarthritis, and to establish correlations between levels of these naturally occurring IL-1 inhibitors and indices of disease activity and joint destruction.

Methods: Levels of IL-1Ra, sIL-1RI, and sIL-1RII were measured in plasma samples from patients with chronic polyarthritis, using specific radioimmunoassays. Levels were correlated with indices of disease activity and joint destruction.

Results: Plasma levels of IL-1Ra, sIL-1RI, and sIL-1RII were significantly higher in polyarthritis patients than in controls. IL-1Ra levels correlated positively with all indices of disease activity and joint destruction (P < 0.0001). In contrast, sIL-1RII levels correlated negatively with indices of joint destruction, such as the Larsen score in the wrist (P < 0.04). Interestingly, sIL-1RII levels were higher in patients with nondestructive arthritis (Larsen score < or =1) than in patients with destructive arthritis. Levels of sIL-1RI did not correlate with indices of disease activity or joint destruction.

Conclusion: The present findings indicate that increased levels of IL-1Ra, a natural antiinflammatory acute-phase protein, may reflect increased production and activity of IL-1. In contrast, endogenous sIL-1RII, unlike sIL-1RI, may constitute a natural antiinflammatory factor in chronic polyarthritis. These differences should be taken into account when these antiinflammatory molecules are considered as prognostic markers or for therapeutic use.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Arthritis / blood*
  • Arthritis / physiopathology
  • Biomarkers
  • Chronic Disease
  • Female
  • Humans
  • Male
  • Middle Aged
  • Radioimmunoassay
  • Receptors, Interleukin-1 / antagonists & inhibitors*
  • Receptors, Interleukin-1 / blood*
  • Solubility


  • Biomarkers
  • Receptors, Interleukin-1