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Ann Rheum Dis. 1993 March; 52(3): 232–234.
PMCID: PMC1005024

Serum interleukin 6 levels in rheumatoid arthritis: correlations with clinical and laboratory indices of disease activity.


In rheumatoid synovium interleukin 6 (IL-6) is the most abundantly expressed cytokine. Increased serum levels have been previously reported in patients with rheumatoid arthritis (RA). In this study serum IL-6 levels were measured in a well defined cohort using a bioassay (B9 cells) and levels were correlated with conventional clinical and laboratory indices of disease activity. Levels were significantly higher in serum from patients with RA (median 55 IU/ml; interquartile range 28-139) compared with serum from disease (median 7 IU/ml; 1-23) and normal controls (median 10 IU/ml; 7-12). No difference was observed between men and women. Levels did not correlate with disease duration. Significant associations were observed between IL-6 and C reactive protein and between the Ritchie articular index and duration of morning stiffness. No other correlations were observed. The value of these findings in the monitoring of RA and as an indicator of response to second line treatment needs to be established.

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Selected References

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  • Houssiau FA, Devogelaer JP, Van Damme J, de Deuxchaisnes CN, Van Snick J. Interleukin-6 in synovial fluid and serum of patients with rheumatoid arthritis and other inflammatory arthritides. Arthritis Rheum. 1988 Jun;31(6):784–788. [PubMed]
  • Bhardwaj N, Santhanam U, Lau LL, Tatter SB, Ghrayeb J, Rivelis M, Steinman RM, Sehgal PB, May LT. IL-6/IFN-beta 2 in synovial effusions of patients with rheumatoid arthritis and other arthritides. Identification of several isoforms and studies of cellular sources. J Immunol. 1989 Oct 1;143(7):2153–2159. [PubMed]
  • Guerne PA, Zuraw BL, Vaughan JH, Carson DA, Lotz M. Synovium as a source of interleukin 6 in vitro. Contribution to local and systemic manifestations of arthritis. J Clin Invest. 1989 Feb;83(2):585–592. [PMC free article] [PubMed]
  • Helle M, Boeije L, Aarden LA. Functional discrimination between interleukin 6 and interleukin 1. Eur J Immunol. 1988 Oct;18(10):1535–1540. [PubMed]
  • Holt I, Cooper RG, Hopkins SJ. Relationships between local inflammation, interleukin-6 concentration and the acute phase protein response in arthritis patients. Eur J Clin Invest. 1991 Oct;21(5):479–484. [PubMed]
  • Swaak AJ, van Rooyen A, Nieuwenhuis E, Aarden LA. Interleukin-6 (IL-6) in synovial fluid and serum of patients with rheumatic diseases. Scand J Rheumatol. 1988;17(6):469–474. [PubMed]
  • Thompson PW, Silman AJ, Kirwan JR, Currey HL. Articular indices of joint inflammation in rheumatoid arthritis. Correlation with the acute-phase response. Arthritis Rheum. 1987 Jun;30(6):618–623. [PubMed]
  • Möttönen TT, Hannonen P, Toivanen J, Rekonen A, Oka M. Value of joint scintigraphy in the prediction of erosiveness in early rheumatoid arthritis. Ann Rheum Dis. 1988 Mar;47(3):183–189. [PMC free article] [PubMed]
  • Dasgupta B, Corkill M, Kirkham B, Gibson T, Panayi G. Serial estimation of interleukin 6 as a measure of systemic disease in rheumatoid arthritis. J Rheumatol. 1992 Jan;19(1):22–25. [PubMed]
  • Ganter U, Arcone R, Toniatti C, Morrone G, Ciliberto G. Dual control of C-reactive protein gene expression by interleukin-1 and interleukin-6. EMBO J. 1989 Dec 1;8(12):3773–3779. [PubMed]
  • Mackiewicz A, Ganapathi MK, Schultz D, Brabenec A, Weinstein J, Kelley MF, Kushner I. Transforming growth factor beta 1 regulates production of acute-phase proteins. Proc Natl Acad Sci U S A. 1990 Feb;87(4):1491–1495. [PubMed]
  • Hollen CW, Henthorn J, Koziol JA, Burstein SA. Elevated serum interleukin-6 levels in patients with reactive thrombocytosis. Br J Haematol. 1991 Oct;79(2):286–290. [PubMed]

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