title: Clinical correlations of infliximab trough levels and antibodies to infliximab in South Korean patients with Crohn's disease.
abstract: OBJECTIVE
  To investigate the clinical implications of infliximab trough levels (IFX-TLs) and antibodies to infliximab (ATI) levels in Crohn's disease (CD) patients in Asian countries.
  
  
  METHODS
  IFX-TL and ATI level were measured using prospectively collected samples obtained with informed consent from CD patients being treated at Asan Medical Center, South Korea. We analyzed the correlations between IFX-TLs/ATI levels and the clinical activity of CD (quiescentvsactive disease) based on the CD activity index, C-reactive protein level, and physician's judgment of patients' clinical status at enrollment. The impact of concomitant immunomodulators was also investigated.
  
  
  RESULTS
  This study enrolled 138 patients with CD (84 with quiescent and 54 with active disease). In patients with quiescent and active diseases, the median IFX-TLs were 1.423 μg/mL and 0.163 μg/mL, respectively (P< 0.001) and the median ATI levels were 8.064 AU/mL and 11.209 AU/mL, respectively (P< 0.001). In the ATI-negative and -positive groups, the median IFX-TLs were 1.415 μg/mL and 0.141 μg/mL, respectively (P< 0.001). In patients with and without concomitant immunomodulator use, there were no differences in IFX-TLs (0.632 μg/mL and 1.150 μg/mL, respectively;P= 0.274) or ATI levels (8.655 AU/mL and 9.017 AU/mL, respectively;P= 0.083).
  
  
  CONCLUSIONS
  IFX-TL/ATI levels were well correlated with the clinical activity in South Korean CD patients. Our findings support the usefulness of IFX-TLs/ATI levels in treating CD patients receiving IFX in clinical practice.
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Eun Hye
authors.initials: EH
authors.lastname: Oh
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Ko
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Hyungil
authors.initials: H
authors.lastname: Seo
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Kiju
authors.initials: K
authors.lastname: Chang
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Gwang-Un
authors.initials: GU
authors.lastname: Kim
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Eun Mi
authors.initials: EM
authors.lastname: Song
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Myeongsook
authors.initials: M
authors.lastname: Seo
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Ho-Su
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Sung Wook
authors.initials: SW
authors.lastname: Hwang
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Dong-Hoon
authors.initials: DH
authors.lastname: Yang
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Byong Duk
authors.initials: BD
authors.lastname: Ye
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Jeong-Sik
authors.initials: JS
authors.lastname: Byeon
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Myung
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Suk-Kyun
authors.initials: SK
authors.lastname: Yang
authors.affiliation: Eun Hye Oh, Department of Internal Medicine, University of Ulsan College of Medicine, Asan Medical Center, Seoul 05505, South Korea.
authors.forename: Sang Hyoung
authors.initials: SH
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism; D003424:Crohn Disease / Q000097:blood* / Q000276:immunology*; D005260:Female; D005765:Gastrointestinal Agents / Q000097:blood / Q000276:immunology; D006801:Humans; D007249:Inflammation; D000069285:Infliximab / Q000097:blood* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D056910:Republic of Korea; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000906:Antibodies; D005765:Gastrointestinal Agents; D002097:C-Reactive Protein; D000069285:Infliximab
keywords: Antibody; Crohn’s disease; Drug effect; Drug monitoring; Infliximab