title: Genomic characterization of remission in juvenile idiopathic arthritis.
abstract: BACKGROUND
  The attainment of remission has become an important end point for clinical trials in juvenile idiopathic arthritis (JIA), although we do not yet have a full understanding of what remission is at the cell and molecular level.
  
  
  METHODS
  Two independent cohorts of patients with JIA and healthy child controls were studied. RNA was prepared separately from peripheral blood mononuclear cells (PBMC) and granulocytes to identify differentially expressed genes using whole genome microarrays. Expression profiling results for selected genes were confirmed by quantitative, real-time polymerase chain reaction (RT-PCR).
  
  
  RESULTS
  We found that remission in JIA induced by either methotrexate (MTX) or MTX plus a TNF inhibitor (etanercept, Et) (MTX + Et) is characterized by numerous differences in gene expression in peripheral blood mononuclear cells and in granulocytes compared with healthy control children; that is, remission is not a restoration of immunologic normalcy. Network analysis of the differentially expressed genes demonstrated that the steroid hormone receptor superfamily member hepatocyte nuclear factor 4 alpha (HNF4α) is a hub in several of the gene networks that distinguished children with arthritis from controls. Confocal microscopy revealed that HNF4a is present in both T lymphocytes and granulocytes, suggesting a previously unsuspected role for this transcription factor in regulating leukocyte function and therapeutic response in JIA.
  
  
  CONCLUSIONS
  These findings provide a framework from which to understand therapeutic response in JIA and, furthermore, may be used to develop strategies to increase the frequency with which remission is achieved in adult forms of rheumatoid arthritis.
authors.forename: Kaiyu
authors.initials: K
authors.lastname: Jiang
authors.forename: Mark
authors.initials: M
authors.lastname: Frank
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Chen
authors.forename: Jeanette
authors.initials: J
authors.lastname: Osban
authors.forename: James N
authors.initials: JN
authors.lastname: Jarvis
mesh_terms: D000293:Adolescent; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001171:Arthritis, Juvenile / Q000188:drug therapy / Q000235:genetics* / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D000068800:Etanercept; D005260:Female; D020869:Gene Expression Profiling; D006098:Granulocytes / Q000378:metabolism; D051557:Hepatocyte Nuclear Factor 4 / Q000235:genetics*; D006801:Humans; D007074:Immunoglobulin G / Q000627:therapeutic use; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use; D018613:Microscopy, Confocal; D020411:Oligonucleotide Array Sequence Analysis; D060888:Real-Time Polymerase Chain Reaction; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use; D012074:Remission Induction; D013601:T-Lymphocytes / Q000378:metabolism; D059467:Transcriptome
chemical_list: D018501:Antirheumatic Agents; C496592:HNF4A protein, human; D051557:Hepatocyte Nuclear Factor 4; D007074:Immunoglobulin G; D018124:Receptors, Tumor Necrosis Factor; D000068800:Etanercept; D008727:Methotrexate