Characterization of IL10 and IL10 Receptor Expression Patterns in Pediatric Patients with Ulcerative Colitis

Introduction: IL10 is a key anti-inflammatory cytokine. There is limited data on IL10 and IL10 receptor (IL10R) expression in the gut, and whether these patterns are altered in patients with ulcerative colitis (UC). We hypothesized that patients with active UC display altered colonic IL10 and IL10R expression.

Methods: Formalin-fixed paraffin-embedded rectal and transverse colon sections were collected from subjects with normal endoscopy without history of inflammatory bowel disease, UC patients with extensive or pan-colitis (E3/E4) and UC patients with limited distal disease (E1/E2; n=8-10 subjects per group). Immunohistochemistry was performed to assess expression patterns of IL10, IL10R1 and IL10R2. Intensity of stains was calculated by an image analysis software (ImagePro Plus).

Results: IL10 expression was significantly increased in rectal and transverse colon biopsies of the E3/E4 group, compared to control subjects and the E1/E2. IL10R1 expression was higher in transverse colon sections of the E3/E4 group, compared to control subjects. There was a significant difference in IL10R1 expression, comparing rectal to transverse colon sections of the E3/E4. No differences in expression of IL10R2 were demonstrated between all groups. We found no correlation between PUCAI scores, or microscopic severity, and IL10, IL10R1 or IL10R2 expression in rectal sections among patients.

Conclusion: Colonic IL10 and IL10R1 expression is elevated in pediatric patients with extensive or pancolitis. Given IL10’s anti-inflammatory properties, additional studies are required to determine whether signaling through the IL10R is altered among these patients, and define specifically what regulates IL10 expression in the intestine, in steady state and during inflammation.