title: Serum YKL-40, a potential new marker of disease activity in patients with inflammatory bowel disease.
abstract: BACKGROUND
  YKL-40 is secreted by macrophages and neutrophils and is a growth factor for vascular endothelial cells and fibroblasts. Elevated serum concentrations of YKL-40 are found in patients with diseases characterized by inflammation or ongoing fibrosis. The aim of this study was to seek association between serum YKL-40 in patients with ulcerative colitis (UC) and Crohn disease (CD) and clinical disease activity.
  
  
  METHODS
  One-hundred-and-sixty-four patients with UC and 173 patients with CD were studied. The Simple Clinical Colitis Activity Index (SCCAI) and the Harvey-Bradshaw (H-B) score were used to assess disease activity. Serum YKL-40 (determined by ELISA) was related to C-reactive protein (CRP) and disease activity.
  
  
  RESULTS
  In patients with UC, the median serum YKL-40 rose with increasing disease activity, and patients with severe active disease had higher serum YKL-40 (median 59 microg/L (95% CI: 26-258 microg/L), P < 0.001) than patients with inactive UC (33 microg/L (19-163)) and age-matched controls (43 microg/L (20-124)). Patients with severe active CD had higher serum YKL-40 (59 microg/L (21-654), P < 0.001) than age-matched controls, but not higher than inactive CD patients (43 microg/L (17-306)). Serum YKL-40 was elevated in 41% of the patients with severe UC, in 10% with inactive UC, in 46% with severe CD and in 30% with inactive CD. Serum YKL-40 correlated with SCCAI in UC patients but not with H-B score in CD patients. In both patient groups, low correlations were found between serum YKL-40 and CRP, albumin and leucocytes.
  
  
  CONCLUSIONS
  Serum YKL-40 is elevated in patients with active IBD and may be complementary to inflammatory markers and clinical characteristics in the assessment of disease activity.
authors.affiliation: Dept. of Gastroenterology and Rheumatology, Hvidovre Hospital, University of Copenhagen, Denmark. ida@vind.to
authors.forename: I
authors.initials: I
authors.lastname: Vind
authors.forename: J S
authors.initials: JS
authors.lastname: Johansen
authors.forename: P A
authors.initials: PA
authors.lastname: Price
authors.forename: P
authors.initials: P
authors.lastname: Munkholm
mesh_terms: D054392:Adipokines; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001324:Autoantigens / Q000097:blood*; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis / Q000096:biosynthesis* / Q000276:immunology; D000071451:Chitinase-3-Like Protein 1; D005260:Female; D006023:Glycoproteins / Q000096:biosynthesis* / Q000097:blood / Q000276:immunology; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000097:blood / Q000276:immunology*; D037102:Lectins; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index
chemical_list: D054392:Adipokines; D001324:Autoantigens; D015415:Biomarkers; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins; D002097:C-Reactive Protein