title: Fecal calprotectin is a clinically relevant biomarker of mucosal healing in patients with quiescent ulcerative colitis.
abstract: OBJECTIVE
  Calprotectin is an abundant protein in neutrophils, which infiltrate the mucosa during inflammation. Fecal calprotectin (FC) level has shown correlation with disease activity in ulcerative colitis (UC) patients. Additionally, FC level is expected to indicate mucosal healing (MH). This study was to see the significance of FC for predicting MH in patients with quiescent UC.
  
  
  METHODS
  A total of 112 patients with quiescent UC were included. After taking blood and stool samples, patients underwent total colonoscopy, and the Mayo endoscopic subscore was recorded. FC was measured by fluorescence enzyme immunoassay. C-reactive protein, hemoglobin, erythrocyte sedimentation rate, and serum albumin were measured as conventional biomarkers. MH was defined as Mayo 0 or 0 and 1, and receiver-operator characteristic analyses were undertaken to determine the significance levels of measurements.
  
  
  RESULTS
  Data from 105 patients were available. Eleven patients showed Mayo ≥ 2. The median (interquartile range) of FC level of all patients was 115 µg/g (45.4-420). The area under the curve (AUC) in receiver operator characteristic analysis of FC to predict Mayo 0 and 1 was 0.869 with a cut-off value of 200 µg/g yielding 67% sensitivity and 91% specificity, which were the best among all biomarkers. However, the power of FC to predict Mayo 0 was modest; the AUC was 0.639 and cut-off value 194 µg/g with 71% sensitivity and 58% specificity.
  
  
  CONCLUSIONS
  Based on the findings of this study, we believe that FC is a clinically relevant biomarker of MH in patients with quiescent UC. Other favorable features of FC test include feasibility and non-invasiveness.
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Showa University, School of Medicine, Tokyo, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Yamaguchi
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Showa University, School of Medicine, Tokyo, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Takeuchi
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Showa University, School of Medicine, Tokyo, Japan.
authors.forename: Katsuhito
authors.initials: K
authors.lastname: Arai
authors.affiliation: Department of Gastroenterology, St Luke's International Hospital, Tokyo, Japan.
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Fukuda
authors.affiliation: Division of Gastroenterology, Showa University Fujigaoka Hospital, Yokohama, Japan.
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kuroki
authors.affiliation: Division of Gastroenterology, Showa University Fujigaoka Hospital, Yokohama, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Asonuma
authors.affiliation: Division of Gastroenterology, Showa University Fujigaoka Hospital, Yokohama, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology and Hepatology, The Jikei University School of Medicine, Tokyo, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Saruta
authors.affiliation: Department of Internal Medicine, Division of Gastroenterology, Showa University, School of Medicine, Tokyo, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Yoshida
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000032:analysis; D003093:Colitis, Ulcerative / Q000473:pathology* / Q000503:physiopathology*; D003113:Colonoscopy; D005243:Feces / Q000737:chemistry*; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000502:physiology*; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex
keywords: biomarker; fecal calprotectin; mucosal healing; ulcerative colitis