title: Serum calprotectin as a biomarker for Crohn's disease.
abstract: OBJECTIVE
  In Crohn's disease, correlation between clinical assessment and disease activity at tissue level is weak. Our aim was to evaluate the value of serum calprotectin as a biomarker for Crohn's disease.
  
  
  METHODS
  The STORI trial patients (n=115) were studied at baseline, in clinical remission before infliximab withdrawal, or at the time of relapse after infliximab withdrawal. Forty healthy controls were also studied. Serum calprotectin level was measured by ELISA. Data were analyzed through correlation analyses, Kaplan Meier curves and Cox model, using available Crohn's Disease Activity Index (CDAI), Crohn's Disease Endoscopic Index of Severity (CDEIS), fecal calprotectin and C-reactive protein levels (hsCRP).
  
  
  RESULTS
  Median serum calprotectin was 8892 ng/mL (range: 410-125,000 ng/mL) in Crohn disease patients as compared with 1318 ng/mL (range: 215.8-3770 ng/mL) in controls (P<0.0001). Serum calprotectin was significantly higher for active disease (median=19,584 ng/mL) than for inactive disease (median=8353 ng/mL) (P<0.0001). Serum calprotectin correlated with hsCRP (r=0.4092, P<0.0001) and CDAI (r=0.4442, P<0.0001), but not with CDEIS, on the contrary to fecal calprotectin (r=0.6458, 0.5515, 0.2577 with P<0.0001, P<0.0001, P=0.019 respectively). In multivariate analysis, serum calprotectin used as a discrete variable (threshold: 5675 ng/ml), appeared complementary to hsCRP (>5 mg/l) and fecal calprotectin (>250 μg/g) to predict relapse after infliximab withdrawal (P=0.0173, 0.0024 and 0.0002; HR: 3.191, 3.561 and 4.120).
  
  
  CONCLUSIONS
  As a CD biomarker, serum calprotectin has a similar profile as hsCRP. It is also complementary to fecal calprotectin and hsCRP for prediction of relapse after infliximab withdrawal.
authors.affiliation: Hepato-Gastroenterology and Digestive Oncology Department, Liège University Hospital, CHU and GIGA-R, University of Liège, Liège, Belgium.
authors.forename: M-A
authors.initials: MA
authors.lastname: Meuwis
authors.forename: G
authors.initials: G
authors.lastname: Vernier-Massouille
authors.forename: J C
authors.initials: JC
authors.lastname: Grimaud
authors.forename: Y
authors.initials: Y
authors.lastname: Bouhnik
authors.forename: D
authors.initials: D
authors.lastname: Laharie
authors.forename: E
authors.initials: E
authors.lastname: Piver
authors.forename: L
authors.initials: L
authors.lastname: Seidel
authors.forename: J F
authors.initials: JF
authors.lastname: Colombel
authors.forename: E
authors.initials: E
authors.lastname: Louis
mesh_terms: D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D003424:Crohn Disease / Q000097:blood* / Q000188:drug therapy; D016099:Endoscopy, Gastrointestinal; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D000069285:Infliximab; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis / Q000097:blood*; D008297:Male; D011237:Predictive Value of Tests; D012008:Recurrence; D012074:Remission Induction; D012720:Severity of Illness Index; D028761:Withholding Treatment
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000911:Antibodies, Monoclonal; D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex; D002097:C-Reactive Protein; D000069285:Infliximab
keywords: Biomarker; CD; CDAI; CDEIS; Crohn's Disease Activity Index; Crohn's Disease Endoscopic Index of Severity; Crohn's disease; IBD; Inflammatory Bowel Disease; Infliximab; Relapse prediction; Serum calprotectin; high sensitivity CRP; hsCRP