Increased level of YKL-40 in sera from patients with early rheumatoid arthritis: a new marker for disease activity

Rheumatol Int. 2001 Jul;20(5):192-6. doi: 10.1007/s002960100115.


YKL-40 is a newly discovered major secretory protein of human chondrocytes and synoviocytes. We measured serum levels of YKL-40 in 52 patients with early onset rheumatoid arthritis (RA) by enzyme-linked immunosorbent assay (ELISA) during a 2-year prospective follow-up, correlating values with laboratory and clinical variables and radiographic progression. Levels at baseline before antirheumatic therapy were significantly higher in patients than in healthy controls. The levels of YKL-40 correlated with laboratory and clinical markers of disease activity both at baseline and during follow-up. Baseline YKL-40 values correlated with baseline Larsen scores but did not predict radiographic progression. Baseline and mean YKL-40 values did not differ between fast and slow radiological progressions. Mean YKL-40 levels correlated with the number of swollen joints but were not predictors of radiographic progression. These results suggest that in early RA, serum YKL-40 is an inflammatory marker correlating with disease activity. However, its levels do not predict clinical course or radiographic progression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipokines
  • Adult
  • Aged
  • Aged, 80 and over
  • Arthritis, Rheumatoid / blood*
  • Arthritis, Rheumatoid / diagnostic imaging
  • Arthritis, Rheumatoid / physiopathology
  • Arthrography
  • Biomarkers
  • Chitinase-3-Like Protein 1
  • Disease Progression
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Glycoproteins / blood*
  • Humans
  • Joints / pathology
  • Lectins
  • Male
  • Middle Aged
  • Prospective Studies
  • Severity of Illness Index
  • Time Factors


  • Adipokines
  • Biomarkers
  • CHI3L1 protein, human
  • Chitinase-3-Like Protein 1
  • Glycoproteins
  • Lectins