title: Functional status of peripheral blood T-cells in ischemic stroke patients.
abstract: Stroke is a major cause of disability and leading cause of death in the northern hemisphere. Only recently it became evident that cerebral ischemia not only leads to brain tissue damage and subsequent local inflammation but also to a dramatic loss of peripheral blood T-cells with subsequent infections. However, only scarce information is available on the activation status of surviving T cells. This study therefore addressed the functional consequences of immunological changes induced by stroke in humans. For this purpose peripheral blood T-cells were isolated from 93 stroke patients and the expression of activation makers was determined. In addition ex vivo stimulation assays were applied to asses the functionality of T cells derived from blood of stroke patients. Compared to healthy controls, stroke patients demonstrated an enhanced surface expression of HLA-DR (p<0.0001) and CD25 (p = 0.02) on T cells, revealing that stroke leads to T cell activation, while CTLA-4 remained undetectable. In vitro studies revealed that catecholamines inhibit CTLA-4 upregulation in activated T cells. Ex vivo, T cells of stroke patients proliferated unimpaired and released increased amounts of the proinflammatory cytokine TNF-alpha (p<0.01) and IL-6 (p<0.05). Also, in sera of stroke patients HMGB1 concentrations were increased (p = 0.0002). The data demonstrate that surviving T cells in stroke patients remain fully functional and are primed towards a TH1 response, in addition we provide evidence that catecholamine mediated inhibition of CTLA-4 expression and serum HMGB1 release are possible mediators in stroke induced activation of T cells.
authors.affiliation: Department of Neurology, University of Greifswald, Greifswald, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Vogelgesang
authors.forename: Verena E L
authors.initials: VE
authors.lastname: May
authors.forename: Uwe
authors.initials: U
authors.lastname: Grunwald
authors.forename: Maren
authors.initials: M
authors.lastname: Bakkeboe
authors.forename: Soenke
authors.initials: S
authors.lastname: Langner
authors.forename: Henry
authors.initials: H
authors.lastname: Wallaschofski
authors.forename: Christof
authors.initials: C
authors.lastname: Kessler
authors.forename: Barbara M
authors.initials: BM
authors.lastname: Bröker
authors.forename: Alexander
authors.initials: A
authors.lastname: Dressel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000097:blood; D002545:Brain Ischemia / Q000097:blood*; D060908:CTLA-4 Antigen; D016022:Case-Control Studies; D015331:Cohort Studies; D016207:Cytokines / Q000097:blood; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000097:blood; D024243:HMGB1 Protein / Q000097:blood; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000097:blood; D008213:Lymphocyte Activation; D008875:Middle Aged; D020521:Stroke / Q000097:blood*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D015703:Antigens, CD; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D016207:Cytokines; D006684:HLA-DR Antigens; D024243:HMGB1 Protein; D053645:Interleukin-2 Receptor alpha Subunit