Xu Peng-cheng, Lin Shan, Yang Xiao-wei, Gu Dong-Mei, Yan Tie-kun, Wei Li, Wang Bao-li
Department of Nephrology, Tianjin Medical University General Hospital, Tianjin, 300052, China.
Department of Nephrology, Shandong Provincial Hospital affiliated to Shandong University, Jinan, Shandong, 250021, China.
BMC Immunol. 2015 Mar 3;16:10. doi: 10.1186/s12865-015-0077-0.
C-reactive protein (CRP) exerts prothrombotic effects through dissociating from pentameric CRP (pCRP) into modified or monomeric CRP (mCRP). However, although the high prevalence of venous thromboembolism (VTE) in patients with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has been identified, it remains unclear whether the high levels of circulating pCRP potentially contribute to this hypercoagulable state in AAV. ANCA can induce the generation of neutrophil extracellular traps (NETs). In this study, the NETs-dependent generation of mCRP from pCRP and the influences of mCRP on the activation of coagulation system and inflammatory response in AAV were investigated.
NETs were induced after TNF-α primed neutrophils were incubated with ANCA-containing IgG. After ANCA-induced netting neutrophils were incubated statically with platelet-rich plasma (PRP) containing mCRP (60 μg/mL), the proportion of platelets expressing CD62p increased significantly, while no increased CD62p expression of platelets was observed after static incubation with PRP containing pCRP (60 μg/mL). Under flow conditions, perfusing immobilized ANCA-induced netting neutrophils with pCRP-containing PRP caused platelets activation and mCRP deposition. The newly generated mCRP induced platelets activation on ANCA-induced netting neutrophils, enhanced D-dimer formation, and enhanced high mobility group box 1 secretion by platelets.
Under flow conditions, ANCA-induced netting neutrophils can activate platelets and then prompt the formation of mCRP on activated platelets. Then the newly generated mCRP can further enhance the activation of platelets, the process of thrombogenesis, and the inflammatory response. So the high level of circulating pCRP is not only a sensitive marker for judging the disease activity, but also a participant in the pathophysiology of AAV.
C反应蛋白（CRP）通过从五聚体CRP（pCRP）解离为修饰型或单体CRP（mCRP）发挥促血栓形成作用。然而，尽管已确定抗中性粒细胞胞浆抗体（ANCA）相关血管炎（AAV）患者中静脉血栓栓塞（VTE）的高患病率，但尚不清楚循环中高水平的pCRP是否可能导致AAV的这种高凝状态。ANCA可诱导中性粒细胞胞外陷阱（NETs）的产生。在本研究中，研究了NETs依赖的pCRP生成mCRP以及mCRP对AAV中凝血系统激活和炎症反应的影响。
用含ANCA的IgG孵育经TNF-α预处理的中性粒细胞后可诱导产生NETs。将ANCA诱导形成NETs的中性粒细胞与含mCRP（60μg/mL）的富血小板血浆（PRP）静态孵育后，表达CD62p的血小板比例显著增加，而与含pCRP（60μg/mL）的PRP静态孵育后未观察到血小板CD62p表达增加。在流动条件下，用含pCRP的PRP灌注固定化的ANCA诱导形成NETs的中性粒细胞可导致血小板活化和mCRP沉积。新生成的mCRP可诱导ANCA诱导形成NETs的中性粒细胞上的血小板活化，增强D-二聚体形成，并增强血小板高迁移率族蛋白B1的分泌。
在流动条件下，ANCA诱导形成NETs的中性粒细胞可激活血小板，进而促使活化血小板上形成mCRP。然后新生成的mCRP可进一步增强血小板活化、血栓形成过程和炎症反应。因此，循环中高水平的pCRP不仅是判断疾病活动的敏感标志物，也是AAV病理生理学的参与者。
