TY - JOUR

T1 - Cartilage oligomeric matrix protein in patients with juvenile idiopathic arthritis: relation to growth and disease activity

AU - Bjørnhart, Birgitte

AU - Juul, Anders

AU - Nielsen, Susan

AU - Zak, Marek

AU - Svenningsen, Pernille

AU - Müller, Klaus

N1 - Keywords: Adult; Arthritis, Juvenile Rheumatoid; Blood Platelets; C-Reactive Protein; Cartilage, Articular; Child; Child Development; Cohort Studies; Extracellular Matrix; Extracellular Matrix Proteins; Female; Glycoproteins; Growth Disorders; Humans; Insulin-Like Growth Factor I; Male; Prognosis

PY - 2009

Y1 - 2009

N2 - OBJECTIVE: Cartilage oligomeric matrix protein (COMP) has been identified as a prognostic marker of progressive joint destruction in rheumatoid arthritis. In this population based study we evaluated associations between plasma concentrations of COMP, disease activity, and growth velocity in patients with recent-onset juvenile idiopathic arthritis (JIA). COMP levels in JIA and healthy children were compared with those in healthy adults. Plasma levels of insulin-like growth factor I (IGF-1), which has been associated with COMP expression and growth velocity, were studied in parallel. METHODS: 87 patients with JIA entered the study, including oligoarticular JIA (n = 34), enthesitis-related arthritis (n = 8), polyarticular rheumatoid factor (RF)-positive JIA (n = 2), polyarticular RF-negative JIA (n = 27), systemic JIA (n = 6), and undifferentiated JIA (n = 10). Plasma levels of COMP were measured by ELISA and IGF-1 by a radioimmunoassay. RESULTS: Significantly higher COMP levels [mean 18.9 U/l (95% CI 17.3-20.5)] were found in healthy children compared with healthy adults [mean 10.7 U/l (95% CI 9.4-12.1)] (p < 0.0001). COMP levels in the JIA patients [mean 13.5 U/l (95% CI 12.4-14.7)] were significantly reduced compared to healthy children (p < 0.0001), and correlated negatively with C-reactive protein (CRP; r = -0.29, p = 0.01) and thrombocyte count (r = -0.28, p = 0.02). COMP levels in the JIA patients correlated positively with growth velocity (cm/yr) (r = 0.38, p = 0.0003) and growth velocity (SDS) (r = 0.29, p = 0.007). CONCLUSION: We found reduced COMP levels in children with JIA compared with healthy children. COMP levels in JIA correlated negatively with inflammatory activity as evaluated by CRP and the thrombocyte counts, and were associated with reduced growth rate.

AB - OBJECTIVE: Cartilage oligomeric matrix protein (COMP) has been identified as a prognostic marker of progressive joint destruction in rheumatoid arthritis. In this population based study we evaluated associations between plasma concentrations of COMP, disease activity, and growth velocity in patients with recent-onset juvenile idiopathic arthritis (JIA). COMP levels in JIA and healthy children were compared with those in healthy adults. Plasma levels of insulin-like growth factor I (IGF-1), which has been associated with COMP expression and growth velocity, were studied in parallel. METHODS: 87 patients with JIA entered the study, including oligoarticular JIA (n = 34), enthesitis-related arthritis (n = 8), polyarticular rheumatoid factor (RF)-positive JIA (n = 2), polyarticular RF-negative JIA (n = 27), systemic JIA (n = 6), and undifferentiated JIA (n = 10). Plasma levels of COMP were measured by ELISA and IGF-1 by a radioimmunoassay. RESULTS: Significantly higher COMP levels [mean 18.9 U/l (95% CI 17.3-20.5)] were found in healthy children compared with healthy adults [mean 10.7 U/l (95% CI 9.4-12.1)] (p < 0.0001). COMP levels in the JIA patients [mean 13.5 U/l (95% CI 12.4-14.7)] were significantly reduced compared to healthy children (p < 0.0001), and correlated negatively with C-reactive protein (CRP; r = -0.29, p = 0.01) and thrombocyte count (r = -0.28, p = 0.02). COMP levels in the JIA patients correlated positively with growth velocity (cm/yr) (r = 0.38, p = 0.0003) and growth velocity (SDS) (r = 0.29, p = 0.007). CONCLUSION: We found reduced COMP levels in children with JIA compared with healthy children. COMP levels in JIA correlated negatively with inflammatory activity as evaluated by CRP and the thrombocyte counts, and were associated with reduced growth rate.

U2 - 10.3899/jrheum.080942

DO - 10.3899/jrheum.080942

M3 - Journal article

C2 - 19605679

VL - 36

SP - 1749

EP - 1754

JO - Journal of Rheumatology

JF - Journal of Rheumatology

SN - 0315-162X

IS - 8

ER -