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Promotion of Hypercoagulability in Antineutrophil Cytoplasmic Antibody–Associated Vasculitis by C5a‐Induced Tissue Factor–Expressing Microparticles and Neutrophil Extracellular Traps
Author(s) -
Huang YiMin,
Wang Huan,
Wang Chen,
Chen Min,
Zhao MingHui
Publication year - 2015
Publication title -
arthritis and rheumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.106
H-Index - 314
eISSN - 2326-5205
pISSN - 2326-5191
DOI - 10.1002/art.39239
Subject(s) - neutrophil extracellular traps , tissue factor , immunology , anti neutrophil cytoplasmic antibody , antibody , medicine , thrombin , proteinase 3 , vasculitis , c5a receptor , microbiology and biotechnology , inflammation , complement system , platelet , coagulation , pathology , autoantibody , biology , disease
Objective Patients with antineutrophil cytoplasmic antibody–associated vasculitis (AAV) have a high frequency of venous thromboembolic events and a hypercoagulable state. As C5a‐primed neutrophils play an important role in the development of AAV, we investigated whether C5a‐induced neutrophil tissue factor (TF)–expressing microparticles (MPs) and neutrophil extracellular traps (NETs) might promote hypercoagulability in AAV. Methods TF‐expressing MPs were measured by flow cytometry. TF‐expressing NETs were assessed by confocal microscopy. Levels of thrombin–antithrombin complexes were determined by enzyme‐linked immunosorbent assay. The effect of C5a in sera from AAV patients was evaluated by treating neutrophils with C5a receptor antagonist before incubation with sera from AAV patients with active disease. Results Treatment of C5a‐primed neutrophils with antineutrophil cytoplasmic antibody (ANCA)–positive IgG resulted in the release of TF‐bearing MPs and NETs. Neutrophils from healthy donors treated with sera from patients with active AAV released TF‐bearing MPs and NETs, which were abolished by treatment with C5a receptor antagonist. Involvement of TF in MP‐ or NET‐dependent thrombin generation was indicated by the findings of antibody neutralization studies. NETs with thrombin‐generating capacity were demonstrated by DNase I treatment. Conclusion C5a‐primed neutrophils produce TF‐expressing MPs and NETs after stimulation with ANCAs, indicating a mechanism for hypercoagulability in AAV that was not previously recognized.