Peking University First Hospital and Peking University, Beijing, China.
Arthritis Rheumatol. 2015 Oct;67(10):2780-90. doi: 10.1002/art.39239.
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.
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.
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.
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.
抗中性粒细胞胞浆抗体相关性血管炎（AAV）患者存在静脉血栓栓塞事件和高凝状态的高频率。由于 C5a 预激活的中性粒细胞在 AAV 的发展中发挥重要作用，我们研究了 C5a 诱导的中性粒细胞组织因子（TF）表达的微颗粒（MPs）和中性粒细胞胞外陷阱（NETs）是否可能促进 AAV 的高凝状态。
通过流式细胞术测量 TF 表达的 MPs。通过共焦显微镜评估 TF 表达的 NETs。通过酶联免疫吸附试验测定凝血酶-抗凝血酶复合物的水平。通过在用 C5a 受体拮抗剂处理中性粒细胞后，用来自患有活动性 AAV 的患者的血清孵育，评估来自 AAV 患者的血清中 C5a 的作用。
用抗中性粒细胞胞浆抗体（ANCA）阳性 IgG 处理 C5a 预激活的中性粒细胞会导致释放 TF 携带的 MPs 和 NETs。来自健康供体的中性粒细胞用来自患有活动性 AAV 的患者的血清处理后会释放 TF 携带的 MPs 和 NETs，这可以通过用 C5a 受体拮抗剂处理来消除。抗体中和研究的结果表明 TF 参与了 MP 或 NET 依赖性凝血酶生成。具有产生凝血酶能力的 NETs 通过 DNase I 处理得到证明。
用 ANCAs 刺激后，C5a 预激活的中性粒细胞产生 TF 表达的 MPs 和 NETs，这表明 AAV 中的高凝状态存在以前未被认识到的机制。
