title: Gene expression analysis of peripheral cells for subclassification of pediatric inflammatory bowel disease in remission.
abstract: OBJECTIVE
  In current clinical practice, optimal treatment of inflammatory bowel disease (IBD) aims at the induction and maintenance of clinical remission. Clinical remission is apparent when laboratory markers of inflammation are normal and clinical symptoms are absent. However, sub-clinical inflammation can still be present. A detailed analysis of the immune status during this inactive state of disease may provide a useful tool to categorize patients with clinical remission into subsets with variable states of immune activation.
  
  
  METHODS
  By using Affymetrix GeneChips, we analysed RNA gene expression profiles of peripheral blood leukocytes from pediatric IBD patients in clinical remission and controls. We performed (un)supervised clustering analysis of IBD-associated genes and applied Ingenuity® pathway software to identify specific molecular profiles between patients.
  
  
  RESULTS
  Pediatric IBD patients with disease in clinical remission display heterogeneously distributed gene expression profiles that are significantly distinct from controls. We identified three clusters of IBD patients, each displaying specific expression profiles of IBD-associated genes.
  
  
  CONCLUSIONS
  The expression of immune- and IBD-associated genes in peripheral blood leukocytes from pediatric IBD patients in clinical remission was different from healthy controls, indicating that sub-clinical immune mechanisms are still active during remission. As such, RNA profiling of peripheral blood may allow for non-invasive patient subclassification and new perspectives in treatment regimes of IBD patients in the future.
authors.affiliation: Department of Paediatrics, Erasmus MC - Sophia Children's Hospital, Rotterdam, The Netherlands ; Department of Paediatric Gastroenterology, Wilhelmina Children's Hospital, UMC Utrecht, Utrecht, The Netherlands.
authors.forename: Pieter P E
authors.initials: PP
authors.lastname: van Lierop
authors.forename: Sigrid M
authors.initials: SM
authors.lastname: Swagemakers
authors.forename: Charlotte I
authors.initials: CI
authors.lastname: de Bie
authors.forename: Sabine
authors.initials: S
authors.lastname: Middendorp
authors.forename: Peter
authors.initials: P
authors.lastname: van Baarlen
authors.forename: Janneke N
authors.initials: JN
authors.lastname: Samsom
authors.forename: Wilfred F J
authors.initials: WF
authors.lastname: van Ijcken
authors.forename: Johanna C
authors.initials: JC
authors.lastname: Escher
authors.forename: Peter J
authors.initials: PJ
authors.lastname: van der Spek
authors.forename: Edward E S
authors.initials: EE
authors.lastname: Nieuwenhuis
mesh_terms: D000293:Adolescent; D020869:Gene Expression Profiling; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000235:genetics* / Q000473:pathology; D008297:Male