Mucosal Interleukin-10 depletion in steroid-refractory Crohn's disease patients

Abstract

Background: Previous studies suggested that Interleukin-10 (IL-10) depletion in Crohn's disease (CD) could predict outcome.

Aim: To determine IL-10 in blood and at different intestinal locations in patients with active CD and to assess its potential prognostic capacity to identify aggressive CD.

Methods: Twenty-three patients with CD were included. Ulcerative colitis (UC), infectious colitis and healthy individuals acted as controls. Serum and mucosal samples were taken at baseline and 1 month after steroid initiation in CD patients. Patients were classified according to steroid response. Control samples were obtained from different intestinal locations. IL-10 expression was measured with real-time polymerase chain reaction, immunofluorescence (intestine) and ELISA (serum, biopsy cultures' supernatants and tissue homogenates).

Results: CD and UC showed an increase in IL-10 messenger RNA (mRNA) versus controls (p < .0001) in mucosa, whereas IL-10 protein secretion was increased in all types of intestinal inflammation (p < .001). No differences in IL-10 mRNA were found in CD at baseline regarding steroid response, but levels decreased in non-responders versus responders (p = .027) and were restored with rescue therapy. Serum IL-10 was increased in steroid-refractory CD at baseline and after treatment.

Conclusions: Abnormal IL-10 levels in refractory patients in both mucosa and blood have physiopathological relevance and may have potential clinical applications.

Keywords: Crohn's disease; Interleukin-10; inflammatory bowel disease; intestinal compartmentalization; steroid resistance.

Figure 1

Interleukin‐10 (IL‐10) expression in different intestinal regions (ileum, right, and left colon) of controls (A, C, E) (n = 10 paired samples) and inflamed mucosa of patients with Crohn's disease (B, D, F) (n = 9 ileal and n = 12 colonic, non‐paired samples). Gene expression (A, B); secreted protein levels in culture supernatant of mucosal explants (C, D) and total protein of tissue homogenates (E, F). Line graph shows trends in data for the different intestinal regions. Bar graph represents median values and whiskers above and below 5%−95% percentile. Friedman Test (A, C, E); Mann−Whitney U Test (B, D, F). *p < .05. In (B) measurements are expressed as fold change over the samples of controls.

Figure 2

Interleukin‐10 (IL‐10) expression in controls (n = 24), Crohn's disease (n = 21), ulcerative colitis (n = 7), and infectious colitis (n = 5) (Gene expression [A], secreted protein expression in culture supernatant of mucosal explants [B] and total protein of tissue homogenates [C]). Bar graph represents median values and whiskers above and below 5%−95% percentile. Kruskall−Wallis Test. *p < .05 versus controls; **p < .005 versus controls; ***p < .0005 versus controls.

Figure 3

Interleukin‐10 gene (IL‐10) expression in inflamed mucosa of Crohn's disease according to steroid response at (A) baseline before treatment, (B) 1 month after steroid initiation and (C) after rescue treatment in steroid‐sensitive (n = 5), steroid‐dependent (n = 8), and steroid‐refractory patients (n = 8). Bar graph represents median values and whiskers above and below 5%−95% percentile. Kruskall−Wallis Test. *p < .05 versus steroid‐sensitive patients.

Figure 4

Interleukin‐10 (IL‐10) levels in peripheral blood of controls (n = 12), Crohn's disease (CD, n = 25), ulcerative colitis (n = 7), and infectious colitis (n = 4) patients (A). In CD patients, IL‐10 levels are provided at baseline before treatment (B), 1 month after steroid initiation (C), and after rescue treatment (for those nonresponders that required immunosuppressants or biologics) (D). Results are expressed as pg of protein per ml in sera. Bar graph represents median values and whiskers above and below 5%−95% percentile. Mann−Whitney U Test (A); Kruskall−Wallis Test (B, C, D). *p < .05.