title: Serum and synovial cartilage oligomeric matrix protein levels in early and established rheumatoid arthritis.
abstract: OBJECTIVE
  To assess cartilage oligomeric matrix protein (COMP) levels in serum and synovial fluid in patients with early and established rheumatoid arthritis (RA), and to correlate the levels with clinical, laboratory and radiological characteristics.
  
  
  METHODS
  The study included 24 female RA patients. Full medical history was taken, thorough clinical examination and laboratory investigations performed, and body mass index (BMI) recorded. Radiological damage was assessed according to the modified Larsen score. Disease activity score 28 (DAS28) was calculated. The control group comprised 30 age- and gender-matched healthy subjects. Serum and synovial COMP levels were determined by enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  Mean patient age was 44.04 ± 10.5 years. Of the 24 patients, 12 had early RA and 12 had established disease with joint destruction; 5 of each group had knee effusion. Serum COMP was significantly higher in patients (19.54 ± 5.47 µg/ml) compared to controls (5.93 ± 1.95 µg/ml; p < 0.001) and was also significantly higher in patients with established disease (23.9 ± 3.1 µg/ml) compared to those in early stages (15.1 ± 3.2 µg/ml; p < 0.001). Synovial COMP was also significantly increased in established compared to early-stage RA (31.2 ± 9.8 µg/ml vs. 51.6 ± 10.4 µg/ml; p = 0.013). Serum and synovial COMP significantly correlated with age, disease duration, BMI, DAS28 and modified Larsen score. On performing regression analysis in RA patients, only BMI could predict the serum level of COMP (p = 0.02).
  
  
  CONCLUSIONS
  COMP is a promising biomarker for disease activity in RA, making it a potential therapeutic target. The obvious correlation with the BMI throws light on the importance of weight control not only in osteoarthritis (OA), but also in RA.
authors.affiliation: Internal Medicine Department, National Research Centre, -, Egypt.
authors.forename: A O
authors.initials: AO
authors.lastname: El Defrawy
authors.affiliation: Rheumatology Department, Faculty of Medicine, Cairo University, Cairo, Egypt. gheitamer@hotmail.com.
authors.forename: T A
authors.initials: TA
authors.lastname: Gheita
authors.affiliation: Internal Medicine Department, National Research Centre, -, Egypt.
authors.forename: H M
authors.initials: HM
authors.lastname: Raslan
authors.affiliation: Clinical Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: M M
authors.initials: MM
authors.lastname: El Ansary
authors.affiliation: Rheumatology Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
authors.forename: A H
authors.initials: AH
authors.lastname: El Awar
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism*; D064236:Cartilage Oligomeric Matrix Protein / Q000097:blood / Q000378:metabolism*; D002908:Chronic Disease; D019281:Dimerization; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013583:Synovial Membrane / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D064236:Cartilage Oligomeric Matrix Protein
keywords: Biomarker; Body mass index; Enzyme-linked immunosorbent assay; Inflammation; Osteoarthritis