Interleukin-6 levels in synovial fluids of patients with rheumatoid arthritis correlated with the infiltration of inflammatory cells in synovial membrane

Rheumatol Int. 2006 Oct;26(12):1096-100. doi: 10.1007/s00296-006-0143-2.


To compare the histological appearance of synovial membrane and interleukin (IL)-6 levels in synovial fluids of patients with rheumatoid arthritis (RA). Synovial tissue and synovial fluids were obtained from 51 knee joints with RA undergoing synovectomy or joint replacements. A histological inflammation score was determined based on the hyperplasia of the synovial lining and infiltration of inflammatory cells. The concentrations of IL-6 in synovial fluids were measured by ELISA. The association between IL-6 levels and histological findings was evaluated. We found a positive correlation between the infiltration of inflammation cells in synovial tissues and the concentration of IL-6 in synovial fluids. The IL-6 level in synovial fluid partially reflects histological synovial inflammation.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Arthritis, Rheumatoid / pathology*
  • Biomarkers / analysis
  • C-Reactive Protein / analysis
  • Female
  • Humans
  • Interleukin-6 / analysis*
  • Male
  • Middle Aged
  • Synovial Fluid / chemistry*
  • Synovial Membrane / pathology*


  • Biomarkers
  • Interleukin-6
  • C-Reactive Protein