Relationship between sonographic parameters and YKL-40 levels in rheumatoid arthritis

Rheumatology International, 04/02/2012

Kazakova M et al. – The findings suggest that YKL–40 might be implicated in the pathogenesis of the disease and could indicate the level of joint inflammation.


  • In this study, the authors evaluated YKL–40 levels in serum and synovial fluid of patients with rheumatoid arthritis in comparison with the ultrasonographic findings.
  • YKL–40 levels were measured by enzyme–linked immunosorbent assay in 25 patients with active rheumatoid arthritis and in 40 healthy subjects.
  • B mode and power Doppler were performed to determine synovial thickening and vascularization.


  • Serum YKL–40 level in patients was significantly higher than the concentration in healthy controls (P < 0.01).
  • In patients with rheumatoid arthritis, the level of the glycoprotein in synovial fluid was remarkably elevated compared to the serum level (P = 0.003).
  • The B mode and power Doppler scores correlated to YKL–40 in serum and synovial fluid (P = 0.07).
  • Serum YKL–40 levels were related positively to serum markers of inflammation such as C–reactive protein (P = 0.004) and erythrocyte sedimentation rate (P = 0.003).
  • This study is the first to demonstrate a relationship between YKL–40 levels and ultrasonographic examinations in Bulgarian patients with rheumatoid arthritis.

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