Intest Res  
Trough level of infliximab is useful for assessing mucosal healing in Crohn’s disease: a prospective cohort study
Akihiro Koga1, Toshiyuki Matsui1, Noritaka Takatsu1, Yasumichi Takada1, Masahiro Kishi1, Yutaka Yano1, Takahiro Beppu1, Yoichiro Ono1, Kazeo Ninomiya1, Fumihito Hirai1, Takashi Nagahama1, Takashi Hisabe1, Yasuhiro Takaki1, Kenshi Yao1, Hirotsugu Imaeda2, Akira Andoh2
1Department of Gastroenterology, Fukuoka University Chikushi Hospital, Chikushino, 2Department of Medicine, Shiga University of Medical Science, Otsu, Japan
Correspondence to: Toshiyuki Matsui, Department of Gastroenterology, Fukuoka University Chikushi Hospital, 1-1-1-Zokumyoin, Chikushino 818-8502, Japan. Tel: +81-92-921-1011, Fax: +81-92-928-3890, E-mail:
Received: March 20, 2017; Revised: September 28, 2017; Accepted: October 16, 2017; Published online: March 14, 2018.
© Korean Association for the Study of Intestinal Diseases. All rights reserved.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Background/Aims: Decreased trough levels of infliximab (TLI) and antibodies to infliximab (ATI) are associated with loss of response (LOR) in Crohn’s disease. Two prospective studies were conducted to determine whether TLI or ATI better correlates with LOR (Study 1), and whether TLI could become a predictor of mucosal healing (MH) (Study 2). Methods: Study 1 was conducted in 108 patients, including those with LOR and remission to compare ATI and TLI in discriminating the two conditions based on receiver operating characteristic (ROC) curve analyses. Study 2 involved 35 patients who were evaluated endoscopically. Results: Study 1: There were no differences between the two assays in ROC curve analyses; the TLI cutoff value for LOR was 2.6 μg/mL (sensitivity, 70.9%; specificity, 79.2%), and the ATI cutoff value was 4.9 μg/mL (sensitivity, 65.5%; specificity, 67.9%). The AUROC (area under the ROC curve) of TLI was greater than that of ATI. AUROC was useful for discriminating between the two conditions. Study 2: The TLI was significantly higher in the colonic MH group than in the non-MH group (2.7 μg/mL vs. 0.5 μg/mL, P=0.032). Conclusions: TLI is better than ATI for clinically diagnosing LOR, and a correlation was observed between TLI and colonic MH.
Keywords: Crohn disease; Infliximab trough level; Mucosal healing; Loss of response; Antibodies to infliximab

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