title: Raised human cartilage glycoprotein-39 plasma levels in patients with rheumatoid arthritis and other inflammatory conditions.
abstract: OBJECTIVE
  To evaluate plasma human cartilage glycoprotein (HC gp-39) as a possible marker for the presence and/or activity of rheumatoid arthritis (RA) and other inflammatory conditions.
  
  
  BACKGROUND
  HC gp-39 is a secretory product of chondrocytes, synovial cells, macrophages, and neutrophils. HC gp-39, also described as YKL-40, was found to be a marker of joint disease and tissue injury in RA and various other diseases.
  
  
  METHODS
  Levels of HC gp-39 were determined by a sandwich enzyme linked immunosorbent assay (ELISA) in 47 patients with RA, 47 with osteoarthritis (OA), 24 with systemic lupus erythematosus (SLE), 24 with inflammatory bowel disease (IBD), and in 47 healthy controls. A disease activity score was assessed in the patients with RA, SLE, and IBD.
  
  
  RESULTS
  The plasma level of HC gp-39 in the RA patient group was significantly higher than in the other patient groups and healthy controls. The level in patients with OA, SLE, and IBD was also significantly higher than the HC gp-39 level found in the healthy control group. HC gp-39 levels in patients with RA correlated positively with the ESR and IgM rheumatoid factor level but not with other variables of disease activity. In the patients with SLE and IBD no correlation was found with the disease activity score.
  
  
  CONCLUSIONS
  The plasma level of HC gp-39 is increased in inflammatory conditions with and without joint disease (SLE, IBD, OA, and RA). Thus increased levels of HC gp-39 do not only reflect joint disease but also reflect inflammation or tissue degradation in various conditions. Notably, the highest level of HC gp-39 was found in patients with RA. Only in the RA patient group was a correlation between HC gp-39 plasma levels and some laboratory variables of disease activity found.
authors.affiliation: Department of Rheumatology, LUMC, Leiden, The Netherlands. kvos@rheumatology.azl.nl
authors.forename: K
authors.initials: K
authors.lastname: Vos
authors.forename: P
authors.initials: P
authors.lastname: Steenbakkers
authors.forename: A M
authors.initials: AM
authors.lastname: Miltenburg
authors.forename: E
authors.initials: E
authors.lastname: Bos
authors.forename: M W
authors.initials: MW
authors.lastname: van Den Heuvel
authors.forename: R A
authors.initials: RA
authors.lastname: van Hogezand
authors.forename: R R
authors.initials: RR
authors.lastname: de Vries
authors.forename: F C
authors.initials: FC
authors.lastname: Breedveld
authors.forename: A M
authors.initials: AM
authors.lastname: Boots
mesh_terms: D054392:Adipokines; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000473:pathology; D000071451:Chitinase-3-Like Protein 1; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood; D037102:Lectins; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000097:blood
chemical_list: D054392:Adipokines; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins