Serum soluble interleukin 6 (IL-6) receptor and IL-6/soluble IL-6 receptor complex in systemic juvenile rheumatoid arthritis.

Abstract

By using a sandwich ELISA, soluble human IL-6 receptor (sIL-6 R) levels were measured in the sera of 20 healthy children and of 25 patients with systemic juvenile rheumatoid arthritis (JRA). In patients with systemic JRA, serum sIL-6 R levels (114.6 +/- 37.7 ng/ml) were significantly lower (P < 0.01) than those of healthy children (161.2 +/- 45.5 ng/ml). Serum sIL-6 R levels were negatively correlated (r = -0.610, P < 0.001) with serum IL-6 levels measured with the B9 cells. The serum IL-6/sIL-6 R complex was detected using an ELISA based on a monoclonal antibody to IL-6 for capture and on a monoclonal antibody to human sIL-6 R for detection. Healthy controls had little, if any, detectable serum IL-6/sIL-6 R complex (OD 0.024 +/- 0.027), while the majority of patients with systemic JRA presented measurable serum IL-6/sIL-6 R complex (OD 0.492 +/- 0.546). IL-6 levels estimated in the circulating IL-6/sIL-6 R complexes were in the range of nanograms per milliliter and approximately 20-fold higher than those measured by the B9 cells. Since serum C-reactive protein concentrations were much more correlated with serum levels of IL-6/sIL-6 R complexes (r = 0.713, r2 = 0.51, P < 0.0001) than with the serum IL-6 levels measured with the B9 cells (r = 0.435, r2 = 0.19, P = 0.05), the large quantities of serum IL-6 present in IL-6/sIL-6 R complexes appear to be biologically relevant in vivo, at least as far as the induction by IL-6 of acute phase protein production.

• Authors: F De Benedetti, M Massa, P Pignatti, S Albani, D Novick, A Martini
• Journal: The Journal of clinical investigation (J Clin Invest) Vol. 93 Issue 5 Pg. 2114-9 (May 1994) ISSN: 0021-9738 [Print] United States
• PMID: 8182142 (Publication Type: Journal Article)

Chemical References

• Interleukin-6
• Macromolecular Substances
• Receptors, Interleukin
• Receptors, Interleukin-6

Topics

• Adolescent
• Arthritis, Juvenile (blood, classification, etiology)
• Child
• Child, Preschool
• Enzyme-Linked Immunosorbent Assay (methods)
• Humans
• Interleukin-6 (isolation & purification, metabolism)
• Macromolecular Substances
• Protein Binding
• Receptors, Interleukin (isolation & purification, metabolism)
• Receptors, Interleukin-6
• Solubility