title: Reduced Numbers and Impaired Function of Regulatory T Cells in Peripheral Blood of Ischemic Stroke Patients.
abstract: OBJECTIVE
  Regulatory T cells (Tregs) have been suggested to modulate stroke-induced immune responses. However, analyses of Tregs in patients and in experimental stroke have yielded contradictory findings. We performed the current study to assess the regulation and function of Tregs in peripheral blood of stroke patients. Age dependent expression of CD39 on Tregs was quantified in mice and men.
  
  
  METHODS
  Total FoxP3(+) Tregs and CD39(+)FoxP3(+) Tregs were quantified by flow cytometry in controls and stroke patients on admission and on days 1, 3, 5, and 7 thereafter. Treg function was assessed by quantifying the inhibition of activation-induced expression of CD69 and CD154 on T effector cells (Teffs).
  
  
  RESULTS
  Total Tregs accounted for 5.0% of CD4(+) T cells in controls and <2.8% in stroke patients on admission. They remained below control values until day 7. CD39(+) Tregs were most strongly reduced in stroke patients. On day 3 the Treg-mediated inhibition of CD154 upregulation on CD4(+) Teff was impaired in stroke patients. CD39 expression on Treg increased with age in peripheral blood of mice and men.
  
  
  CONCLUSIONS
  We demonstrate a loss of active FoxP3(+)CD39(+) Tregs from stroke patient's peripheral blood. The suppressive Treg function of remaining Tregs is impaired after stroke.
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Ruhnau
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Schulze
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: von Sarnowski
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Marie
authors.initials: M
authors.lastname: Heinrich
authors.affiliation: Department of Diagnostic Radiology and Neuroradiology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Sönke
authors.initials: S
authors.lastname: Langner
authors.affiliation: Department of Immunology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Christian
authors.identifier: 0000-0003-0302-1811
authors.initials: C
authors.lastname: Pötschke
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Wilden
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Kessler
authors.affiliation: Department of Immunology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Bröker
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Antje
authors.identifier: 0000-0003-2984-0831
authors.initials: A
authors.lastname: Vogelgesang
authors.affiliation: Department of Neurology, University Medicine Greifswald, 17475 Greifswald, Germany.
authors.forename: Alexander
authors.identifier: 0000-0002-9055-4327
authors.initials: A
authors.lastname: Dressel
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001081:Apyrase / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism; D005260:Female; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D020521:Stroke / Q000276:immunology* / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D001081:Apyrase; C067869:CD39 antigen