Cytokine Imbalance in the Pathogenesis of Rheumatoid Arthritis: The Role of interleukin-1 Receptor Antagonist

Semin Arthritis Rheum. 2001 Apr;30(5 Suppl 2):1-6. doi: 10.1053/sarh.2001.23693.

Abstract

Objectives: To summarize the role of cytokine imbalance in the pathogenesis of rheumatoid arthritis.

Methods: The literature on cytokines in rheumatoid arthritis from American and European medical journals was reviewed.

Results: An important role of interleukin (IL)-1 and tumor necrosis factor (TNF)-alpha in the mediation of tissue damage in the rheumatoid joint has been well established over the past 10 years. The IL-1 family consists of 2 agonists, IL-1alpha and IL-1beta, and a specific naturally occurring receptor antagonist, IL-1Ra. Both forms of IL-1 induce intracellular responses through binding to the type 1 IL-1 receptor (IL-1R) on target cells. IL-1Ra binds to IL-1R with an avidity equal to that of IL-1 but fails to stimulate the cells, thus functioning as an inhibitor of IL-1 binding. Endogenous production of IL-1Ra is an important anti-inflammatory mechanism both in animal models of disease and in human disease. In the rheumatoid synovium, an imbalance exists in this system, because the relative levels of production of IL-1Ra are not adequate to effectively block the proinflammatory effects of IL-1. Studies in different animal models of inflammatory arthritis indicate that a deficiency of IL-1Ra relative to IL-1 leads to more severe disease and even to the spontaneous development of arthritis as observed in IL-1Ra knockout mice. A restoration of the balance between IL-1Ra and IL-1 in human disease can theoretically be achieved through the administration of recombinant IL-1ra protein, gene therapy with the IL-1Ra complementary DNA, or stimulation of production of endogenous IL-1Ra.

Conclusions: An imbalance between proinflammatory cytokines and cytokine antagonists or inhibitors may be one factor predisposing to initiation or perpetuation of rheumatoid synovitis.

Publication types

  • Review

MeSH terms

  • Animals
  • Arthritis, Rheumatoid / etiology*
  • Humans
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-1 / physiology*
  • Sialoglycoproteins / physiology*

Substances

  • IL1RN protein, human
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-1
  • Sialoglycoproteins