title: Impaired suppression of synovial fluid CD4+CD25- T cells from patients with juvenile idiopathic arthritis by CD4+CD25+ Treg cells.
abstract: OBJECTIVE
  Natural CD4+CD25+FoxP3+ Treg cells play a crucial role in maintaining immune homeostasis and controlling autoimmunity. In patients with juvenile idiopathic arthritis (JIA), inflammation occurs despite the increased total numbers of Treg cells in the synovial fluid (SF) compared to the peripheral blood (PB). This study was undertaken to investigate the phenotype of CD4+ T cells in PB and SF from JIA patients, the function of synovial Treg cells, and the sensitivity of PB and SF CD4+CD25- effector T cells to the immunoregulatory properties of Treg cells, and to study the suppression of cytokine secretion from SF effector T cells by Treg cells.
  
  
  METHODS
  The phenotypes of effector T cells and Treg cells of PB and SF from JIA patients and healthy donors were determined by flow cytometry. The functionality of isolated Treg cells and effector T cells was quantified in (3) H-thymidine proliferation assays. Cytokine levels were analyzed using Bio-Plex Pro assay.
  
  
  RESULTS
  Compared to PB, SF showed significantly elevated numbers of activated and differentiated CD4+CD45RO+ T cells. Sensitivity of SF effector T cells to the suppressive effects of Treg cells from both PB and SF was impaired, correlating inversely with the expression of CD69 and HLA-DR. However, SF effector T cell cytokine secretion was partly suppressed by SF Treg cells.
  
  
  CONCLUSIONS
  Our findings indicate that regulation is impaired in the SF of patients with JIA, as shown by the resistance of effector T cells to immunoregulation by functional Treg cells. This resistance of the SF effector T cells might be due to their activated phenotype.
authors.affiliation: University Children's Hospital Tuebingen, Tuebingen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Haufe
authors.forename: Markus
authors.initials: M
authors.lastname: Haug
authors.forename: Carsten
authors.initials: C
authors.lastname: Schepp
authors.forename: Jasmin
authors.initials: J
authors.lastname: Kuemmerle-Deschner
authors.forename: Sandra
authors.initials: S
authors.lastname: Hansmann
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Rieber
authors.forename: Nikolay
authors.initials: N
authors.lastname: Tzaribachev
authors.forename: Toni
authors.initials: T
authors.lastname: Hospach
authors.forename: Jan
authors.initials: J
authors.lastname: Maier
authors.forename: Guenther E
authors.initials: GE
authors.lastname: Dannecker
authors.forename: Ursula
authors.initials: U
authors.lastname: Holzer
mesh_terms: D001171:Arthritis, Juvenile / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D002648:Child; D005260:Female; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000032:analysis*; D008297:Male; D013582:Synovial Fluid / Q000276:immunology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
chemical_list: D053645:Interleukin-2 Receptor alpha Subunit