title: Methotrexate treatment affects effector but not regulatory T cells in juvenile idiopathic arthritis.
abstract: OBJECTIVE
  The balance between Treg and effector T cells (Teff) is crucial for immune regulation in JIA. How MTX, the cornerstone treatment in JIA, influences this balance in vivo is poorly elucidated. The aim of this study was to investigate quantitative and qualitative effects of MTX on Treg and Teff in JIA patients during MTX treatment.
  
  
  METHODS
  Peripheral blood samples were obtained from JIA patients at the start of MTX and 3 and 6 months thereafter. Treg numbers and phenotypes were determined by flow cytometry and suppressive function in allogeneic suppression assays. Teff proliferation upon stimulation with anti-CD3, activation status and intracellular cytokine production were determined by flow cytometry. Effector cell responsiveness to suppression was investigated in autologous suppression assays. Effector cell cytokines in supernatants of proliferation and suppression assays and in plasma were measured by cytokine multiplex assay.
  
  
  RESULTS
  MTX treatment in JIA did not affect Treg phenotype and function. Instead, MTX treatment enhanced, rather than diminished, CD4(+) and CD8(+) T cell proliferation of JIA patients after 6 months of therapy, independent of clinical response. Effector cells during MTX treatment were equally responsive to Treg-mediated suppression. MTX treatment did not attenuate Teff activation status and their capacity to produce IL-13, IL-17, TNF-α and IFN-γ. Similarly to Teff proliferation, plasma IFN-γ concentrations after 6 months were increased.
  
  
  CONCLUSIONS
  This study provides the novel insight that MTX treatment in JIA does not attenuate Teff function but, conversely, enhances T cell proliferation and IFN-γ plasma concentrations in JIA patients.
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands m.bulatovic@umcutrecht.nl.
authors: Maja
authors: M
authors: Bulatović Ćalasan
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Sebastiaan J
authors: SJ
authors: Vastert
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Rianne C
authors: RC
authors: Scholman
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Frederik
authors: F
authors: Verweij
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Mark
authors: M
authors: Klein
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Nico M
authors: NM
authors: Wulffraat
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Berent J
authors: BJ
authors: Prakken
authors: Center for Molecular and Cellular Intervention, Department of Pediatric Immunology, Wilhelmina Children's Hospital, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors: Femke
authors: F
authors: van Wijk
mesh_terms: D000293:Adolescent; D018501:Antirheumatic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001171:Arthritis, Juvenile / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007109:Immunity / Q000187:drug effects; D007371:Interferon-gamma / Q000097:blood; D008297:Male; D008727:Methotrexate / Q000494:pharmacology* / Q000627:therapeutic use; D010641:Phenotype; D011446:Prospective Studies; D016176:T-Lymphocyte Subsets / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D016207:Cytokines; D007371:Interferon-gamma; D008727:Methotrexate
keywords: cytokines; effector T cells; juvenile idiopathic arthritis; methotrexate; regulatory T cells; suppression assays