title: Differential mucosal expression of Th17-related genes between the inflamed colon and ileum of patients with inflammatory bowel disease.
abstract: BACKGROUND
  Immunological and genetic findings implicate Th17 effector cytokines in the pathogenesis of inflammatory bowel disease (IBD). Expression of Th17 pathway-associated genes is mainly studied in colonic disease. The present study assessed the mRNA expression levels of Th17 effector cytokines (IL17A, IL17F, IL21, IL22 and IL26) and genes involved in differentiation (IL6, IL1B, TGFB1, IL23A and STAT3) and recruitment of Th17 cells (CCR6 and CCL20) by quantitative real-time PCR analysis of colonic and ileal biopsies from 22 healthy control subjects, 26 patients with Crohn's disease (CD) and 12 patients with ulcerative colitis (UC). Inflammation was quantified by measuring expression of the inflammatory mediators IL8 and TNF.
  
  
  RESULTS
  Evaluation of mRNA expression levels in colonic and ileal control samples revealed that TNF, TGFB1, STAT3 and CCR6 were expressed at higher levels in the ileum than in the colon. Expression of all the Th17 pathway-associated genes was increased in inflamed colonic samples. The increased expression of these genes was predominantly observed in samples from UC patients and was associated with more intense inflammation. Although increased expression of IL17A, IL17F, IL21 and IL26 was detected in inflamed ileal samples, expression of the indispensable Th17 cell differentiation factors TGFB1 and IL23A, the signaling molecule STAT3 and the Th17 recruitment factors CCR6 and CCL20 were unchanged.
  
  
  CONCLUSIONS
  Our findings suggest that immune regulation is different in colonic and ileal disease, which might have important consequences for therapeutic intervention.
authors.affiliation: Department of Gastroenterology, Ghent University, Ghent, Belgium.
authors.forename: Sara
authors.initials: S
authors.lastname: Bogaert
authors.forename: Debby
authors.initials: D
authors.lastname: Laukens
authors.forename: Harald
authors.initials: H
authors.lastname: Peeters
authors.forename: Lode
authors.initials: L
authors.lastname: Melis
authors.forename: Kim
authors.initials: K
authors.lastname: Olievier
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.forename: Gust
authors.initials: G
authors.lastname: Verbruggen
authors.forename: Jo
authors.initials: J
authors.lastname: Vandesompele
authors.forename: Dirk
authors.initials: D
authors.lastname: Elewaut
authors.forename: Martine
authors.initials: M
authors.lastname: De Vos
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003106:Colon / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007082:Ileum / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D018928:Immunity, Mucosal / Q000235:genetics; D018836:Inflammation Mediators / Q000378:metabolism*; D015212:Inflammatory Bowel Diseases / Q000235:genetics / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000032:analysis; D058504:Th17 Cells / Q000276:immunology / Q000378:metabolism* / Q000473:pathology
chemical_list: D018836:Inflammation Mediators; D012333:RNA, Messenger