title: Tissue factor expression in neutrophil extracellular traps and neutrophil derived microparticles in antineutrophil cytoplasmic antibody associated vasculitis may promote thromboinflammation and the thrombophilic state associated with the disease.
abstract: OBJECTIVE
  Antineutrophil cytoplasmic antibody (ANCA) associated vasculitis (AAV) is characterised by neutrophil activation. An elevated prevalence of venous thromboembolic events has been reported in AAV. Because of the critical role of neutrophils in inflammation associated thrombosis, we asked whether neutrophil tissue factor (TF) may be implicated in the thrombotic diathesis in AAV.
  
  
  METHODS
  Neutrophils from four patients and sera from 17 patients with ANCA associated vasculitis with active disease and remission were studied. TF expression was assessed by immunoblotting and confocal microscopy. Circulating DNA levels were evaluated. TF expressing microparticles (MPs) were measured by flow cytometry and thrombin-antithrombin complex levels by ELISA.
  
  
  RESULTS
  Peripheral blood neutrophils from four patients with active disease expressed elevated TF levels and released TF expressing neutrophil extracellular traps (NETs) and MPs. TF positive NETs were released by neutrophils isolated from the bronchoalveolar lavage and were detected in nasal and renal biopsy specimens. Elevated levels of circulating DNA and TF expressing neutrophil derived MPs were further observed in sera from patients with active disease. Induction of remission attenuated the aforementioned effects. Control neutrophils treated with sera from patients with active disease released TF bearing NETs and MPs which were abolished after IgG depletion. Treatment of control neutrophils with isolated IgG from sera from patients with active disease also resulted in the release of TF bearing NETs. TF implication in MP dependent thrombin generation was demonstrated by antibody neutralisation studies.
  
  
  CONCLUSIONS
  Expression of TF in NETs and neutrophil derived MPs proposes a novel mechanism for the induction of thrombosis and inflammation in active AAV.
authors.affiliation: Laboratory of Molecular Haematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kambas
authors.affiliation: Laboratory of Molecular Haematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Akrivi
authors.initials: A
authors.lastname: Chrysanthopoulou
authors.affiliation: Second Department of Medicine, Athens University School of Medicine, Hippokration General Hospital, Athens, Greece.
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Vassilopoulos
authors.affiliation: Laboratory of Molecular Haematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Eirini
authors.initials: E
authors.lastname: Apostolidou
authors.affiliation: First Department of Internal Medicine, University General Hospital of Alexandroupolis, Alexandroupolis, Greece.
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Skendros
authors.affiliation: Life Sciences Research Unit-FSTC, University of Luxembourg, Walferdange, Luxembourg.
authors.forename: Andreas
authors.initials: A
authors.lastname: Girod
authors.affiliation: Laboratory of Molecular Haematology, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Stella
authors.initials: S
authors.lastname: Arelaki
authors.affiliation: Department of Pneumonology, University General Hospital of Alexandroupolis, Alexandroupolis, Greece.
authors.forename: Marios
authors.initials: M
authors.lastname: Froudarakis
authors.affiliation: First Department of Pathology, Medical School, University of Athens, Athens, Greece.
authors.forename: Lydia
authors.initials: L
authors.lastname: Nakopoulou
authors.affiliation: Department of Pathology, University General Hospital of Alexandroupolis, Alexandroupolis, Greece.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Giatromanolaki
authors.affiliation: Department of Rheumatology, Clinical Immunology and Allergy, University Hospital, Medical School, University of Crete, Heraklion, Greece.
authors.forename: Prodromos
authors.initials: P
authors.lastname: Sidiropoulos
authors.affiliation: Laboratory of Cellular and Molecular Biology, Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupolis, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Koffa
authors.affiliation: Third Department of Internal Medicine, National University of Athens Medical School, Sotiria Hospital, Athens, Greece Biomedical Research Foundation of Academy of Athens, Centre for Immunology and Transplantations, Athens, Greece.
authors.forename: Dimitrios T
authors.initials: DT
authors.lastname: Boumpas
authors.affiliation: Laboratory of Molecular Haematology, Democritus University of Thrace, Alexandroupolis, Greece First Department of Internal Medicine, University General Hospital of Alexandroupolis, Alexandroupolis, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Ritis
authors.affiliation: Laboratory of Molecular Haematology, Democritus University of Thrace, Alexandroupolis, Greece First Department of Internal Medicine, University General Hospital of Alexandroupolis, Alexandroupolis, Greece Department of Internal Medicine III, Division of Vascular Inflammation, Diabetes and Kidney, University Clinic Carl-Gustav-Carus, University of Dresden, Dresden, Germany.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Mitroulis
mesh_terms: D000328:Adult; D000368:Aged; D056648:Anti-Neutrophil Cytoplasmic Antibody-Associated Vasculitis / Q000097:blood* / Q000150:complications / Q000628:therapy; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000097:blood; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D016022:Case-Control Studies; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D065206:Extracellular Traps / Q000378:metabolism*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D008875:Middle Aged; D018375:Neutrophil Activation; D009504:Neutrophils / Q000378:metabolism*; D012074:Remission Induction; D019851:Thrombophilia / Q000209:etiology* / Q000378:metabolism; D013925:Thromboplastin / Q000378:metabolism / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D007074:Immunoglobulin G; D014409:Tumor Necrosis Factor-alpha; D013925:Thromboplastin