Clinical significance of decreased serum concentration of cartilage oligomeric matrix protein in systemic juvenile idiopathic arthritis.
OBJECTIVE
Serum cartilage oligomeric matrix protein (COMP) concentration is elevated in patients with early osteoarthritis and early rheumatoid arthritis, and may be a biomarker of cartilage turnover. We investigated whether serum COMP concentration could be a clinically significant marker of arthritis and/or growth impairment in juvenile idiopathic arthritis (JIA).


METHODS
Specimens were collected from 82 healthy blood donors under 22 years of age with no growth impairment who served as healthy controls, and from 24 patients with JIA (6 with oligoarthritis, 10 with polyarthritis, 8 with systemic JIA) presenting with active arthritis. Serum COMP concentration was determined using a human COMP assay kit.


RESULTS
Serum COMP concentrations were significantly higher in all controls less than 16 years of age than in all controls aged 16 years or older. There was a significant negative correlation between serum COMP concentration and serum C-reactive protein in patients with JIA. Serum COMP concentrations in patients with systemic JIA were significantly lower than those in controls.


CONCLUSIONS
Serum COMP concentrations in healthy children reflected increased cartilage turnover in the growth phase. Because the serum COMP concentration was decreased in cases of systemic JIA in which growth impairment was pronounced, the systemic inflammation occurring in systemic JIA may have an effect on cartilage turnover, which plays an important role in growth. Serum COMP concentration may prove to be a marker that indicates growth impairment in systemic JIA.
Urakami
Tomoko
T
Department of Pediatrics, Okayama University Graduate School of Medicine, Dentistry, Okayama City, Okayama, Japan.
Manki
Akira
A
Inoue
Takuya
T
Oda
Megumi
M
Tanaka
Hiroyuki
H
Morishima
Tsuneo
T
D000293:Adolescent; D001168:Arthritis / Q000097:blood / Q000150:complications / Q000503:physiopathology; D001171:Arthritis, Juvenile / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D002356:Cartilage / Q000378:metabolism; D064236:Cartilage Oligomeric Matrix Protein; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D016326:Extracellular Matrix Proteins / Q000097:blood*; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006130:Growth Disorders / Q000097:blood* / Q000209:etiology / Q000503:physiopathology; D006801:Humans; D008297:Male; D064235:Matrilin Proteins
D015415:Biomarkers; D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D064235:Matrilin Proteins; C577553:TSP5 protein, human; D002097:C-Reactive Protein