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

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.