Activation of Coagulation and Proinflammatory Pathways in Thrombosis with Thrombocytopenia Syndrome and Following COVID-19 Vaccination

Thrombosis with thrombocytopenia syndrome (TTS) is an extremely rare but potentially serious adverse event following immunization with the adenovirus vector-based COVID-19 vaccines Ad26.COV2.S (Janssen / Johnson & Johnson) or ChAdOx1 (AstraZeneca). However, no cases of TTS have been reported in over 1.5 million individuals who received a second immunization with Ad26.COV2.S in the United States, suggesting that anti-vector immunity may reduce TTS risk. Here we show robust stimulation of platelet activation and coagulation pathways and innate immune pathways in patients with TTS but only transient activation of these pathways following vaccination. We evaluated proteomic profiles in 2 patients with TTS and transcriptomic and proteomic profiles in 20 people following an initial dose and a booster dose of Ad26.COV2.S and in 14 people who received the mRNA vaccines BNT162b2 or mRNA-1273. Initial Ad26.COV2.S vaccination induced transient activation of platelet activation and coagulation pathways and innate proinflammatory pathways that resolved by day 7. TTS patients showed enhanced and sustained upregulation of these pathways, whereas a second immunization with Ad26.COV2.S or a reduced initial dose of Ad26.COV2.S resulted in lower activation of these pathways. These data provide insight into TTS pathogenesis and suggest a potential strategy for reducing TTS risk by lowering the dose of Ad26.COV2.S. 30 outbred Indian-origin adult male (10) and female (20) rhesus macaques (Macaca mulatta) were randomly allocated to groups21. Animals were 5-8 kg. All animals were housed at Bioqual, Inc. (Rockville, MD). Animals received a single immunization of 1x1011, 5x1010, 1.125x1010, or 2x109 viral particles (vp) Ad26.COV2.S (Janssen; n = 5/group) or sham (n = 10) by the intramuscular route without adjuvant at week 0. Animal studies were conducted in compliance with all relevant local, state, and federal regulations and were approved by the Bioqual Institutional Animal Care and Use Committee (IACUC). Blood, PBMC, and serum samples were collected at baseline (D1) and on days 1 (D2), 7 (D8), and 14 (D14) following vaccination.

血栓性血小板减少综合征（Thrombosis with thrombocytopenia syndrome, TTS）是接种腺病毒载体新型冠状病毒肺炎疫苗Ad26.COV2.S（杨森/强生）或ChAdOx1（阿斯利康）后发生的极为罕见但可能危及生命的不良事件。然而，美国超过150万名接受Ad26.COV2.S加强免疫的个体中未报告任何TTS病例，这提示抗载体免疫或可降低TTS风险。本研究显示，TTS患者体内存在血小板活化、凝血通路及先天免疫通路的强烈激活，而疫苗接种后仅出现这些通路的一过性激活。我们对2名TTS患者的蛋白质组学特征进行了评估，并对20名接受Ad26.COV2.S初免及加强免疫的个体、14名接种mRNA疫苗BNT162b2或mRNA-1273的个体的转录组学与蛋白质组学特征进行了分析。Ad26.COV2.S初免可诱导血小板活化、凝血通路及先天促炎通路的一过性激活，该激活于第7天消退。TTS患者上述通路的上调更为显著且持续，而接受Ad26.COV2.S加强免疫或降低剂量的Ad26.COV2.S初免则可使这些通路的激活程度降低。本研究数据为TTS的发病机制提供了新见解，并提示通过降低Ad26.COV2.S接种剂量来降低TTS风险的潜在策略。30只印度来源远交系成年恒河猴（Macaca mulatta），其中雄性10只、雌性20只，被随机分配至21个组。受试动物体重为5~8 kg，所有动物均饲养于Bioqual公司（美国马里兰州罗克维尔市）。受试动物于第0周经肌肉注射单剂Ad26.COV2.S（杨森公司；每组n=5）或安慰剂（每组n=10），给药剂量分别为1×10^11、5×10^10、1.125×10^10或2×10^9病毒颗粒（vp），未添加佐剂。本动物实验严格遵循所有相关地方、州及联邦法规开展，并经Bioqual机构动物护理与使用委员会（IACUC）批准。于基线（D1）及疫苗接种后第1天（D2）、第7天（D8）、第14天（D14）采集血液、外周血单个核细胞（peripheral blood mononuclear cell, PBMC）及血清样本。