title: Expression of functional tissue factor in activated T-lymphocytes in vitro and in vivo: A possible contribution of immunity to thrombosis?
abstract: OBJECTIVE
  T-lymphocyte activation plays an important role in the pathophysiology of acute coronary syndromes (ACS). Plaques from ACS patients show a selective oligoclonal expansion of T-cells, indicating a specific, antigen-driven recruitment of T-lymphocytes within the unstable lesions. At present, however, it is not known whether T-cells may contribute directly to thrombosis by expressing functional tissue factor (TF). Accordingly, the aim of the present study was to investigate whether T-cells are able to express functional TF in their activated status.
  
  
  METHODS
  In vitro, CD3(+)-cells, isolated from buffy coats, were stimulated with anti-CD3/CD28 beads, IL-6, TNF-α, IL-17, INF-γ or PMA/ionomycin. Following stimulation, TF expression on cell-surface, at gene and protein levels, as well as its procoagulant activity in whole cells and microparticles was measured. In vivo, TF expression was evaluated in CD3(+)-cells isolated from the aorta and the coronary sinus of ACS-NSTEMI and stable coronary artery disease (SCAD) patients. The presence of CD3(+)-TF(+)cells was also evaluated by immunohistochemistry in thrombi aspirated from ACS-STEMI patients.
  
  
  RESULTS
  PMA/ionomycin and IL-17 plus INF-γ stimulation resulted in a significant TF increase at gene and protein levels as well as at cell-surface expression. This was accompanied by a parallel increase in FXa generation, both in whole cells and in microparticles, indicating that the induced membrane-bound TF was active. Furthermore, transcardiac TF gradient was significantly higher in CD3(+)-cells obtained from ACS-patients compared to SCAD-patients. Interestingly, thrombi from ACS-STEMI patients resulted enriched in CD3(+)-cells, most of them expressing TF.
  
  
  CONCLUSIONS
  Our data demonstrate that activated T-lymphocytes in vitro express functional TF on their membranes, suggesting a direct pathophysiological role of these cells in the thrombotic process; this hypothesis is further supported by the observations in vivo that CD3(+)-cells from coronary circulation of ACS-NSTEMI patients show increased TF levels and that coronary thrombi from ACS-STEMI patients are enriched in CD3(+)-cells expressing TF.
authors.affiliation: Department of Clinical and Experimental Medicine, Section of Clinical Immunology, Second University of Naples, Naples, Italy; Institute of Protein Biochemistry, CNR, Naples, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: De Palma
authors.affiliation: Department of Advanced Biosciences, Section of Cardiology, University of Naples, "Federico II", Naples, Italy.
authors.forename: Plinio
authors.initials: P
authors.lastname: Cirillo
authors.affiliation: Department of Cardiothoracic and Respiratory Sciences, Section of Cardiology, Second University of Naples, Naples, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Ciccarelli
authors.affiliation: Department of Clinical and Experimental Medicine, Section of Clinical Immunology, Second University of Naples, Naples, Italy.
authors.forename: Giusi
authors.initials: G
authors.lastname: Barra
authors.affiliation: Department of Cardiothoracic and Respiratory Sciences, Section of Cardiology, Second University of Naples, Naples, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Conte
authors.affiliation: Department of Advanced Biosciences, Section of Cardiology, University of Naples, "Federico II", Naples, Italy.
authors.forename: Grazia
authors.initials: G
authors.lastname: Pellegrino
authors.affiliation: Department of Clinical and Experimental Medicine, Section of Clinical Immunology, Second University of Naples, Naples, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Pasquale
authors.affiliation: Laboratory of Molecular Medicine and Genomics, Department of Medicine and Surgery, University of Salerno, Baronissi, SA, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Nassa
authors.affiliation: Endocrinology and Experimental Oncology Institute, CNR, Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pacifico
authors.affiliation: Department of Molecular and Cellular Biology and Pathology, University of Naples, "Federico II", Naples, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Leonardi
authors.affiliation: Department of Advanced Biosciences, Section of Cardiology, University of Naples, "Federico II", Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Insabato
authors.affiliation: Endocrinology and Experimental Oncology Institute, CNR, Naples, Italy; Department of Molecular Medicine and Medical Biotechnologies, University "Federico II", Naples, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Calì
authors.affiliation: Department of Cardiothoracic and Respiratory Sciences, Section of Cardiology, Second University of Naples, Naples, Italy. Electronic address: paolo.golino@unina2.it.
authors.forename: Paolo
authors.initials: P
authors.lastname: Golino
authors.affiliation: Department of Cardiothoracic and Respiratory Sciences, Section of Cardiology, Second University of Naples, Naples, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Cimmino
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D000368:Aged; D002478:Cells, Cultured; D017023:Coronary Angiography; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D013925:Thromboplastin / Q000235:genetics* / Q000378:metabolism*; D013927:Thrombosis
chemical_list: D013925:Thromboplastin
keywords: Atherosclerosis; Inflammation; T-lymphocyte; Thrombosis; Tissue factor