title: Relationship between serum infliximab trough levels and endoscopic activities in patients with Crohn's disease under scheduled maintenance treatment.
abstract: OBJECTIVE
  Few data are available to support the clinical relevance of infliximab (IFX) trough levels for prediction of endoscopic disease activity in Crohn's disease (CD). This study evaluated the endoscopic disease activities in relation to clinical outcome using several laboratory markers including serum IFX trough levels in patients with CD undergoing scheduled IFX maintenance treatment.
  
  
  METHODS
  A total of 78 sessions of endoscopy were performed on 45 patients with CD. Endoscopic activity was assessed using the modified Rutgeerts scoring system. IFX trough levels and anti-IFX antibodies (ATIs) were determined by immunoassays.
  
  
  RESULTS
  Endoscopic activity negatively correlated with serum IFX trough levels (Spearman's rank correlation coefficient (ρ) = -0.54, P < 0.0001) and serum albumin levels (ρ = -0.46, P < 0.0001), and positively correlated with CRP (C-reactive protein) levels (ρ = 0.55, P < 0.0001), ESR (erythrocyte sedimentation rate) (ρ = 0.47, P < 0.0001) and fecal calprotectin levels. IFX trough levels and serum albumin levels were significantly elevated in the mucosal healing (MH) group, but ATIs, CRP, ESR and fecal calprotectin levels were significantly elevated in the nonmucosal healing group. Receiver operation curve revealed that the optimal cutoff value of IFX trough levels for identifying normal laboratory markers was 0.6 μg/ml for CRP, 1.0 μg/ml for serum albumin and 1.1 μg/ml for fecal calprotectin. Identification of mucosal healing needed a higher cutoff value of 4.0 μg/ml. Thiopurine treatment did not affect IFX trough and ATI levels.
  
  
  CONCLUSIONS
  Mucosal healing requires higher IFX trough levels, compared to those to achieve normalization of routine clinical markers.
authors.affiliation: Department of Medicine, Shiga University of Medical Science, Seta-Tukinowa, Otsu, 520-2192, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Imaeda
authors.forename: Shigeki
authors.initials: S
authors.lastname: Bamba
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Takahashi
authors.forename: Takehide
authors.initials: T
authors.lastname: Fujimoto
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Ban
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Tsujikawa
authors.forename: Masaya
authors.initials: M
authors.lastname: Sasaki
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Fujiyama
authors.forename: Akira
authors.initials: A
authors.lastname: Andoh
mesh_terms: D000293:Adolescent; D000328:Adult; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood* / Q000276:immunology / Q000627:therapeutic use*; D000906:Antibodies / Q000097:blood; D000911:Antibodies, Monoclonal / Q000097:blood* / Q000276:immunology / Q000627:therapeutic use*; D019540:Area Under Curve; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000378:metabolism; D003424:Crohn Disease / Q000188:drug therapy* / Q000473:pathology; D016099:Endoscopy, Gastrointestinal; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D000069285:Infliximab; D007413:Intestinal Mucosa / Q000503:physiopathology; D039841:Leukocyte L1 Antigen Complex / Q000032:analysis; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012709:Serum Albumin / Q000378:metabolism; D014945:Wound Healing; D055815:Young Adult
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000906:Antibodies; D000911:Antibodies, Monoclonal; D039841:Leukocyte L1 Antigen Complex; D012709:Serum Albumin; D002097:C-Reactive Protein; D000069285:Infliximab