Abnormal IL-1 receptor antagonist production in patients with polymyositis and dermatomyositis

Intern Med. 2000 Feb;39(2):128-35. doi: 10.2169/internalmedicine.39.128.

Abstract

Objective: To examine the relationship between serum levels of interleukin-1 receptor antagonist (IL-1Ra) and its gene expression in peripheral blood mononuclear cells (PBMC) from patients with polymyositis and dermatomyositis (PM/DM).

Methods: IL-1Ra levels in sera from patients and supernatants of unstimulated monocyte cultures were measured by enzyme-linked immunosorbent assay. Expression of IL-1Ra mRNA was analyzed by Northern blotting, and an 86-base pair variable repeat polymorphism in intron 2 of the IL-1Ra gene was determined by polymerase chain reaction.

Results: Serum IL-1Ra was significantly elevated in 27 patients with active-stage PM/DM when compared with levels in 16 patients with inactive-stage PM/DM and 19 normal controls. Serum concentrations of IL-1Ra were correlated with PM/DM disease activity. IL-1Ra mRNA was detected in freshly isolated PBMC from patients with active-stage PM/DM, but not in controls. Moreover, IL-1Ra concentrations were increased significantly in unstimulated monocytes from patients with active-stage PM/DM compared with monocytes from normal controls. However, there were no significant differences in IL-1Ra allele frequencies between patients and normal controls.

Conclusion: Elevation of both IL-1Ra mRNA and protein in sera of patients with active-stage PM/DM suggest that higher levels of serum IL-1Ra may reflect increased IL-1Ra production in myositis, and that IL-1Ra may regulate IL-1-mediated muscle fiber damage in PM/DM.

Publication types

  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Biomarkers / blood
  • Blotting, Northern
  • Creatine Kinase / blood
  • DNA Probes / chemistry
  • Dermatomyositis / blood*
  • Dermatomyositis / genetics
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fructose-Bisphosphate Aldolase / blood
  • Gene Expression
  • Humans
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-1 / blood
  • Male
  • Middle Aged
  • Monocytes / metabolism*
  • Polymerase Chain Reaction
  • Polymorphism, Genetic
  • Polymyositis / blood*
  • Polymyositis / genetics
  • RNA, Messenger / biosynthesis*
  • Receptors, Interleukin-1 / antagonists & inhibitors*
  • Sialoglycoproteins / blood*
  • Sialoglycoproteins / genetics*

Substances

  • Biomarkers
  • DNA Probes
  • IL1RN protein, human
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-1
  • RNA, Messenger
  • Receptors, Interleukin-1
  • Sialoglycoproteins
  • Creatine Kinase
  • Fructose-Bisphosphate Aldolase