Pouchitis is associated with mucosal imbalance between interleukin-8 and interleukin-10

Background: Mucosal lesions of pouchitis are characterized by a neutrophil infiltrate. Interleukin (IL)-8 is the main mediator involved in neutrophil recruitment and is downregulated by IL-10. Aim: To look for an imbalance between IL-8 and IL-10 in patients with pouchitis. Patients/Methods: 18 patients having an ileoanal pouch for ulcerative colitis were studied. Eleven had pouchitis defined by the pouchitis disease activity index of greater than or equal to 7 points and 7 had no history of pouchitis. Biopsies taken at the site of inflammation or in the normal mucosa were scored for the histologic lesions, the intensity of neutrophil infiltration, and the presence of crypt abscesses. Mucosal IL-8 and IL-10 mRNA were quantified by competitive polymerase chain reaction. Results: IL-8, IL-10, and IL-10/IL-8 mRNA were similar in patients with or without pouchitis. IL-8 mRNA levels were significantly higher in patients with a histologic score >2 (p = 0.01) and in patients with crypt abscesses (p = 0.01). IL-10/IL-8 mRNA was significantly lower in patients having a histologic score >2 (p = 0.019), a neutrophil infiltration greater than or equal to 10% (p = 0.013), and crypt abscesses (p = 0.01). Conclusion: Histologic lesions of pouchitis are associated with a mucosal imbalance between IL-8 and IL-10. IL-10 could be proposed as a new treatment for pouchitis.