Background: 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.
Methods: 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.
Results: 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.
Conclusions: 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.
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: email@example.com).
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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