Jevtic Stefan D, Arnold Donald M, Modi Dimpy, Ivetic Nikola, Bissola Anna-Lise, Nazy Ishac
Department of Medicine, Michael G. DeGroote School of Medicine, McMaster University, Hamilton, ON, Canada.
McMaster Centre for Transfusion Research, McMaster University, Hamilton, ON, Canada.
Front Cardiovasc Med. 2022 Oct 24;9:1040196. doi: 10.3389/fcvm.2022.1040196. eCollection 2022.
Coronavirus disease 2019 (COVID-19) is a viral respiratory infection caused by the severe acute respiratory syndrome virus (SARS-CoV-2). Vaccines that protect against SARS-CoV-2 infection have been widely employed to reduce the incidence of symptomatic and severe disease. However, adenovirus-based SARS-CoV-2 vaccines can cause a rare, thrombotic disorder termed vaccine-induced immune thrombotic thrombocytopenia (VITT). VITT often develops in the first 5 to 30 days following vaccination and is characterized by thrombocytopenia and thrombosis in unusual locations (e.g., cerebral venous sinus thrombosis). The diagnosis is confirmed by testing for anti-PF4 antibodies, as these antibodies are capable of platelet activation without any cofactor. It can be clinically challenging to differentiate VITT from a similar disorder called heparin-induced thrombocytopenia (HIT), since heparin is commonly used in hospitalized patients. VITT and HIT have similar pathobiology and clinical manifestations but important differences in testing including the need for PF4-enhanced functional assays and the poor reliability of rapid immunoassays for the detection of anti-platelet factor 4 (PF4) antibodies. In this review we summarize the epidemiology of VITT; highlight similarities and differences between HIT and VITT; and provide an update on the clinical diagnosis of VITT.
2019冠状病毒病（COVID-19）是一种由严重急性呼吸综合征病毒（SARS-CoV-2）引起的病毒性呼吸道感染。预防SARS-CoV-2感染的疫苗已被广泛应用，以降低有症状和严重疾病的发病率。然而，基于腺病毒的SARS-CoV-2疫苗可导致一种罕见的血栓形成性疾病，称为疫苗诱导的免疫性血栓性血小板减少症（VITT）。VITT通常在接种疫苗后的第5至30天出现，其特征是血小板减少和在不寻常部位出现血栓形成（例如，脑静脉窦血栓形成）。通过检测抗PF4抗体来确诊，因为这些抗体能够在没有任何辅助因子的情况下激活血小板。由于肝素在住院患者中常用，因此将VITT与一种类似的疾病肝素诱导的血小板减少症（HIT）区分开来在临床上具有挑战性。VITT和HIT具有相似的病理生物学和临床表现，但在检测方面存在重要差异，包括需要PF4增强功能测定以及快速免疫测定检测抗血小板因子4（PF4）抗体的可靠性较差。在本综述中，我们总结了VITT的流行病学；强调了HIT和VITT之间的异同；并提供了VITT临床诊断的最新情况。
