Interleukin (IL)-9 drives gut inflammation, but its role in Crohn's disease (CD) is unclear. We aimed to analyze correlations between serum IL-9 levels and disease severity and to evaluate their predictive value in relation to the clinical efficacy of infliximab (IFX) in patients with CD.
Between January 2013 and December 2015, 100 consecutive patients with active CD and 50 age- and sex-matched control individuals were recruited from a tertiary center. Their serum IL-9 levels were measured using an enzyme-linked immunosorbent assay. Correlations between the serum IL-9 levels and disease severity were examined. The serum IL-9 level was explored as a predictor of clinical remission and mucosal healing at week 30 in 50 patients for whom IFX therapy was administered.
The serum IL-9 levels were significantly higher in the patients with active CD (22.0 pg/mL) than in the control individuals (6.3 pg/mL) (P < 0.001); they differed according to disease severity (moderate-to-severe CD: 29.1 pg/mL versus mild CD: 12.9 pg/mL) (P < 0.001), and they correlated well with the clinical activity of CD. IFX lowered the serum IL-9 level in patients who achieved efficacy at week 30. The areas under the curves for the IL-9 levels at weeks 14 and 30 that could predict clinical remission and mucosal healing at week 30 were 0.803 and 0.752 and 0.746 and 0.781, respectively.
Serum IL-9 levels correlate with disease severity and the clinical efficacy of IFX in patients with CD, and IL-9 may be a promising novel biomarker for CD monitoring.
Supplemental Digital Content is Available in the Text.Article first published online 20 June 2017.
*Department of Gastroenterology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, P.R. China; and
†Department of Gastroenterology, Sheba Medical Center, Tel Hashomer, Israel.
Address correspondence to: Shenghong Zhang, MD, PhD, Department of Gastroenterology, The First Affiliated Hospital, Sun Yat-sen University, No. 58 Zhongshan Road 2, Guangzhou 510080, P.R. China (e-mail: firstname.lastname@example.org).
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.ibdjournal.org).
Supported by grants from the National Natural Science Foundation of China (#81670498, #81470821, #81630018), the Pearl River S&T Nova Program of Guangzhou (#201610010126), Guangdong Science and Technology (#2014A020212128, #2016A020214006), Science and technology innovation young talents of Guangdong special plan, and the Fundamental Research Fund at Sun Yat-sen University (#15ykpy12).
The authors have no conflict of interest to disclose.
T. Feng and B. Chen contributed equally to the work.
Received January 27, 2017
Accepted May 04, 2017