Serum YKL-40 concentrations in patients with rheumatoid arthritis : relation to disease activity

• Published in: Rheumatology (Oxford, England) England), 1999-07, Vol.38 (7), p.618-626
• Main Authors: JOHANSEN, J. S, STOLTENBERG, M, HANSEN, M, FLORESCU, A, HØRSLEV-PETERSEN, K, LORENZEN, I, PRICE, P. A
• Format: Article
• Language: English
• Subjects: Adipokines; Adult; Aged; Aged, 80 and over; Anti-Inflammatory Agents - therapeutic use; Antirheumatic Agents - therapeutic use; Arthritis, Rheumatoid - blood; Arthritis, Rheumatoid - drug therapy; Biological and medical sciences; Biomarkers - blood; Chitinase-3-Like Protein 1; Disease Progression; Diseases of the osteoarticular system; Female; Glycoproteins - blood; Humans; Inflammatory joint diseases; Lectins; Male; Medical sciences; Methotrexate - therapeutic use; Middle Aged; Prednisolone - therapeutic use; Severity of Illness Index
• ISSN: 1462-0324; 1462-0332
• DOI: 10.1093/rheumatology/38.7.618

YKL-40, also called human cartilage glycoprotein-39, is secreted by chondrocytes, synovial cells, macrophages and neutrophils. Studies have shown that YKL-40 is an autoantigen in rheumatoid arthritis (RA). We evaluated whether serum YKL-40 was related to disease activity in patients with RA. Serum YKL-40 was determined by radioimmunoassay in 156 patients with RA during a 1 yr longitudinal study. Serum YKL-40 was increased in 54% of the patients with clinically active disease. Patients with clinically active disease initially who became inactive after 12 months had a significant decrease in serum YKL-40 (-30%, P < 0.002) and patients who changed from inactive to active disease had an increase in serum YKL-40. Patients who remained active had unchanged serum YKL-40 during the study. Serum YKL-40 decreased rapidly (-24% after 7 days, P < 0.01) during prednisolone therapy, and more slowly in patients treated with methotrexate only (-15% after 60 days, P < 0.01). Patients with early RA (disease duration < 3 yr, n = 50) and a persistently elevated serum YKL-40 were at risk of radiological disease progression as determined by Larsen score. Serum YKL-40 varies according to disease activity in RA, but provides in some respect information different from conventional markers. Our previous studies are consistent with a local release of YKL-40 in the arthritic joint followed by a secondary increase in serum YKL-40. YKL-40 may prove to be a new tool for the study of disease activity and pathophysiology of RA.