B-cell response and thrombotic complications in COVID-19

COVID-19 中的 B 细胞反应和血栓并发症

• 批准号: 10552034
• 负责人: Renren Wen
• 金额: $ 65.99万
• 依托单位: VERSITI WISCONSIN, INC.
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2026-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10552034
• 关键词: 2019-nCoV; Affinity; Antibodies; Antibody Formation; Autoantibodies; Automobile Driving; B-Lymphocytes; Binding; Blood Platelets; C-reactive protein; COVID-19; COVID-19 patient; COVID-19 severity; CXCR3 gene; Cells; Cloning; Coagulation Process; Complement 3d Receptors; Complex; Development; Disease; Endothelium; Fibrin fragment D; Hemostatic function; Heparin; Hospitalization; ITGAX gene; IgG1; Immune response; Immunoglobulin G; Immunoglobulins; Impairment; Incidence; Inflammatory; Interleukin-6; Link; Literature; Memory; Methods; Molecular; Morbidity - disease rate; PF4 Gene; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Plasma; Plasmablast; Platelet Activation; Polysaccharides; SARS-CoV-2 infection; SARS-CoV-2 spike protein; Severities; Structure of germinal center of lymph node; Surface; Symptoms; TNF gene; Testing; Thromboembolism; Thrombosis; Thrombus; Time; Tissues; Venous; Virus; autoreactivity; cross reactivity; enhancing factor; experience; heparin-induced thrombocytopenia; inflammatory marker; inhibiting antibody; monocyte; mortality; neutrophil; novel; novel strategies; protein expression; receptor; receptor binding; response; severe COVID-19; single-cell RNA sequencing; thrombotic; thrombotic complications; transcriptome; venous thromboembolism

Abstract COVID-19 severity/lethality is associated with a dysfunctional inflammatory immune response and a hyper- engagement of pathways driving hemostasis and thrombosis, but the link between the two manifestations is not understood. Compared to patients with mild symptoms, severe COVID-19 patients have stronger IgG reactivity to SARS-CoV-2 virus and its spike protein receptor binding domain (RBD) and a robust B-cell response with a marked increase of the CD11c+CD21- B cells and plasmablast compartments. The incidence of thrombosis and inflammatory disease in severe COVID-19 is unprecedented, manifested by increased plasma inflammatory markers, such as IL-6, tumor necrosis factor alpha, C-reactive protein, and activation of compliment pathway etc., and dysregulated activation of cellular components participating in inflammatory and coagulation responses that include platelets, endothelial, monocytes, and neutrophils. The thrombotic manifestation ranges from arterial, venous, and tissue micro thrombosis to thromboembolism and is predominated by venous thromboembolism. Similar manifestations are observed in catastrophic thrombosis associated with heparin- induced thrombocytopenia and thrombosis (HIT). Patients with catastrophic HIT have the sudden onset of multiple arterial and venous thrombi with, but sometime without, heparin exposure, due to prothrombotic platelet- activating IgGs that recognize platelet factor 4 complexed with heparin polysaccharide (PF4/H). Using methods employed in previous studies of HIT, we studied patients with severe COVID-19 patients and identified PF4/H- reactive, pro-thrombotic IgG antibodies that closely resemble pathogenic antibodies found in patients with HIT in their ability to activate platelets. Surprisingly, levels of PF4/H antibodies in the patient plasma correlated with levels of antibodies specific for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. We cloned RBD-specific antibodies that are able to activate platelets. Compared to those that recognize RBD alone, significantly more B cells recognizing both RBD and PF4/H were CD11c+, CD21- and CXCR3+, which mark a subset of extrafollicular B cells robustly expanded in severe COVID-19. Based on these findings, we hypothesize that SARS-CoV-2 infection drives a subset of RBD-specific B cells to respond via an extrafollicular pathway and generate platelet-activating antibodies that contribute to thrombotic complications but not virus neutralization in severe COVID-19. To test our hypothesis, we will 1) investigate the prothrombotic activity of RBD-specific antibodies in the plasma of hospitalized COVID-19 patients; 2) investigate the expansion of B cells that make RBD-specific platelet-activating antibodies in severe COVID-19; 3) investigate the developmental pathway that governs affinity maturation of RBD and PF4/H cross-reactive B cells. Our proposal studies a novel B-cell/platelet axis in thrombotic complications in COVID-19 and should unravel a large portion of the complex pathogenesis of morbidity/mortality in this disease and suggest new treatment.

抽象的 COVID-19的严重程度/致死性与功能障碍的炎症免疫反应有关 参与驱动止血和血栓形成的途径，但两种表现之间的联系不是 理解。与患有轻度症状的患者相比，严重的Covid-19患者的IgG反应性更强 使用SARS-COV-2病毒及其尖峰蛋白受体结合结构域（RBD）和A稳定的B细胞反应 CD11C+CD21-B细胞和浆膜隔室的明显增加。血栓形成的发生率和 严重的COVID-19中的炎症性疾病是前所未有的，血浆炎症的增加表现出来 标记物，例如IL-6，肿瘤坏死因子α，C反应蛋白和称赞途径的激活 等，以及参与炎症和凝结反应的细胞成分的激活失调 其中包括血小板，内皮，单核细胞和中性粒细胞。血栓形成范围从 动脉，静脉和组织微型血栓形成到血栓栓塞，占主导地位 血栓栓塞。在与肝素相关的灾难性血栓形成中也观察到了类似的表现。 诱导的血小板减少症和血栓形成（命中）。灾难性命中患者突然发作 多个动脉和静脉血栓，但由于血小板血小板 - 激活识别与肝素多糖（PF4/H）复合的血小板因子4的IgG。使用方法 在先前对HIT研究的研究中，我们研究了患有严重COVID-19患者的患者，并确定了PF4/H- 反应性，促性性IgG抗体，与命中患者发现的致病性抗体非常相似 他们激活血小板的能力。令人惊讶的是，患者血浆中PF4/H抗体的水平与 SARS-COV-2尖峰蛋白的受体结合结构域（RBD）的抗体水平。我们克隆了 能够激活血小板的RBD特异性抗体。与仅认识RBD的人相比 识别RBD和PF4/H的B细胞明显更多是CD11C+，CD21-和CXCR3+，它标记为A 在严重的COVID-19中，毛细血管外B细胞的子集稳健地扩展。根据这些发现，我们假设 SARS-COV-2感染驱动RBD特异性B细胞的子集通过外毛状响应 途径和产生血小板激活抗体，导致血栓形成并发症，但不 在严重的共同-19中中和病毒中和。为了检验我们的假设，我们将1）研究促血栓形成 RBD特异性抗体在住院Covid-19患者血浆中的活性； 2）调查扩展 在严重的Covid-19中使RBD特异性血小板激活抗体的B细胞的; 3）调查 控制RBD和PF4/H交叉反应B细胞的亲和力成熟的发育途径。我们的建议 研究在Covid-19的血栓形成并发症中的新型B细胞/血小板轴，应揭开大部分 这种疾病中发病/死亡率的复杂发病机理，并提出了新的治疗方法。