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1.
J Korean Med Sci ; 37(10): e75, 2022 Mar 14.
Article in English | MEDLINE | ID: covidwho-1742199

ABSTRACT

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a rare but life-threatening complication. VITT strongly mimics heparin-induced thrombocytopenia (HIT) and shares clinical features. Heparin is commonly used to prevent coagulation during hemodialysis. Therefore, nephrologists might encounter patients needing dialysis with a history of heparin exposure who developed thrombotic thrombocytopenia after vaccination. A 70-year-old male presented with acute kidney injury and altered mental status due to lithium intoxication. He needed consecutive hemodialysis using heparin. Deep vein thrombosis of left lower extremity and accompanying severe thrombocytopenia of 15,000/µL on 24 days after vaccination and at the same time, nine days after heparin use. Anti-platelet factor 4 antibody test was positive. Anticoagulation with apixaban and intravenous immunoglobulin (IVIG) infusion resolved swelling of his left calf and thrombocytopenia. There were no definitive diagnostic tools capable of differentiating between VITT and HIT in this patient. Although VITT and HIT share treatment with IVIG and non-heparin anticoagulation, distinguishing between VITT and HIT will make it possible to establish a follow-up vaccination plan in a person who has had a thrombocytopenic thrombotic event. Further research is needed to develop the tools to make a clear distinction between the clinical syndromes.


Subject(s)
/adverse effects , Heparin/adverse effects , Purpura, Thrombocytopenic, Idiopathic/etiology , Renal Dialysis/adverse effects , Thrombocytopenia/etiology , Aged , Anticoagulants/adverse effects , Autoantibodies/blood , Diagnosis, Differential , Humans , Immunoglobulin G/blood , Lithium/toxicity , Male , Platelet Count , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/diagnosis , Renal Dialysis/methods , Thrombocytopenia/blood , Thrombocytopenia/diagnosis
2.
Blood ; 139(10): 1564-1574, 2022 03 10.
Article in English | MEDLINE | ID: covidwho-1736325

ABSTRACT

Cases of de novo immune thrombocytopenia (ITP), including a fatality, following SARS-CoV-2 vaccination in previously healthy recipients led to studying its impact in preexisting ITP. In this study, 4 data sources were analyzed: the Vaccine Adverse Events Reporting System (VAERS) for cases of de novo ITP; a 10-center retrospective study of adults with preexisting ITP receiving SARS-CoV-2 vaccination; and surveys distributed by the Platelet Disorder Support Association (PDSA) and the United Kingdom (UK) ITP Support Association. Seventy-seven de novo ITP cases were identified in VAERS, presenting with median platelet count of 3 [1-9] ×109/L approximately 1 week postvaccination. Of 28 patients with available data, 26 responded to treatment with corticosteroids and/or intravenous immunoglobulin (IVIG), and/or platelet transfusions. Among 117 patients with preexisting ITP who received a SARS-CoV-2 vaccine, 19 experienced an ITP exacerbation (any of: ≥50% decline in platelet count, nadir platelet count <30 × 109/L with >20% decrease from baseline, and/or use of rescue therapy) following the first dose and 14 of 70 after a second dose. Splenectomized persons and those who received 5 or more prior lines of therapy were at highest risk of ITP exacerbation. Fifteen patients received and responded to rescue treatment. In surveys of both 57 PDSA and 43 UK patients with ITP, prior splenectomy was associated with worsened thrombocytopenia. ITP may worsen in preexisting ITP or be identified de novo post-SARS-CoV2 vaccination; both situations responded well to treatment. Proactive monitoring of patients with known ITP, especially those postsplenectomy and with more refractory disease, is indicated.


Subject(s)
COVID-19 Vaccines , COVID-19 , Purpura, Thrombocytopenic, Idiopathic , SARS-CoV-2 , Aged , Aged, 80 and over , Blood Platelets/immunology , Blood Platelets/metabolism , COVID-19/blood , COVID-19/epidemiology , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , Female , Humans , Male , Middle Aged , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/chemically induced , Purpura, Thrombocytopenic, Idiopathic/epidemiology , Purpura, Thrombocytopenic, Idiopathic/immunology , Retrospective Studies , Risk Factors , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Splenectomy , United Kingdom/epidemiology
5.
Hematology Am Soc Hematol Educ Program ; 2021(1): 621-627, 2021 12 10.
Article in English | MEDLINE | ID: covidwho-1566500

ABSTRACT

Early in the pandemic, COVID-19-related increases in rates of venous and arterial thromboembolism were seen. Many observational studies suggested a benefit of prophylactic anticoagulation for hospitalized patients using various dosing strategies. Randomized trials were initiated to compare the efficacy of these different options in acutely ill and critically ill inpatients as the concept of immune-mediated inflammatory microthrombosis emerged. We present a case-based review of how we approach thromboembolic prophylaxis in COVID-19 and briefly discuss the epidemiology, the pathophysiology, and the rare occurrence of vaccine-induced thrombotic thrombocytopenia.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19/complications , Purpura, Thrombocytopenic, Idiopathic/etiology , Thrombosis/etiology , Anticoagulants/therapeutic use , Blood Coagulation/drug effects , COVID-19/blood , Critical Illness , Humans , Male , Middle Aged , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Risk Factors , Thrombosis/blood , Thrombosis/drug therapy
6.
Cells ; 10(12)2021 12 01.
Article in English | MEDLINE | ID: covidwho-1542432

ABSTRACT

Autoimmune disorders are often associated with low platelet count or thrombocytopenia. In immune-induced thrombocytopenia (IIT), a common mechanism is increased platelet activity, which can have an increased risk of thrombosis. In addition, or alternatively, auto-antibodies suppress platelet formation or augment platelet clearance. Effects of the auto-antibodies are linked to the unique structural and functional characteristics of platelets. Conversely, prior platelet activation may contribute to the innate and adaptive immune responses. Extensive interplay between platelets, coagulation and complement activation processes may aggravate the pathology. Here, we present an overview of the reported molecular causes and consequences of IIT in the most common forms of autoimmune disorders. These include idiopathic thrombocytopenic purpura (ITP), systemic lupus erythematosus (SLE), antiphospholipid syndrome (APS), drug-induced thrombocytopenia (DITP), heparin-induced thrombocytopenia (HIT), COVID-19 vaccine-induced thrombosis with thrombocytopenia (VITT), thrombotic thrombocytopenia purpura (TTP), and hemolysis, the elevated liver enzymes and low platelet (HELLP) syndrome. We focus on the platelet receptors that bind auto-antibodies, the immune complexes, damage-associated molecular patterns (DAMPs) and complement factors. In addition, we review how circulating platelets serve as a reservoir of immunomodulatory molecules. By this update on the molecular mechanisms and the roles of platelets in the pathogenesis of autoimmune diseases, we highlight platelet-based pathways that can predispose for thrombocytopenia and are linked thrombotic or bleeding events.


Subject(s)
Platelet Activation , Purpura, Thrombocytopenic, Idiopathic/blood , Animals , Humans , Models, Biological , Signal Transduction
7.
Blood ; 139(10): 1564-1574, 2022 03 10.
Article in English | MEDLINE | ID: covidwho-1443789

ABSTRACT

Cases of de novo immune thrombocytopenia (ITP), including a fatality, following SARS-CoV-2 vaccination in previously healthy recipients led to studying its impact in preexisting ITP. In this study, 4 data sources were analyzed: the Vaccine Adverse Events Reporting System (VAERS) for cases of de novo ITP; a 10-center retrospective study of adults with preexisting ITP receiving SARS-CoV-2 vaccination; and surveys distributed by the Platelet Disorder Support Association (PDSA) and the United Kingdom (UK) ITP Support Association. Seventy-seven de novo ITP cases were identified in VAERS, presenting with median platelet count of 3 [1-9] ×109/L approximately 1 week postvaccination. Of 28 patients with available data, 26 responded to treatment with corticosteroids and/or intravenous immunoglobulin (IVIG), and/or platelet transfusions. Among 117 patients with preexisting ITP who received a SARS-CoV-2 vaccine, 19 experienced an ITP exacerbation (any of: ≥50% decline in platelet count, nadir platelet count <30 × 109/L with >20% decrease from baseline, and/or use of rescue therapy) following the first dose and 14 of 70 after a second dose. Splenectomized persons and those who received 5 or more prior lines of therapy were at highest risk of ITP exacerbation. Fifteen patients received and responded to rescue treatment. In surveys of both 57 PDSA and 43 UK patients with ITP, prior splenectomy was associated with worsened thrombocytopenia. ITP may worsen in preexisting ITP or be identified de novo post-SARS-CoV2 vaccination; both situations responded well to treatment. Proactive monitoring of patients with known ITP, especially those postsplenectomy and with more refractory disease, is indicated.


Subject(s)
COVID-19 Vaccines , COVID-19 , Purpura, Thrombocytopenic, Idiopathic , SARS-CoV-2 , Aged , Aged, 80 and over , Blood Platelets/immunology , Blood Platelets/metabolism , COVID-19/blood , COVID-19/epidemiology , COVID-19/immunology , COVID-19/prevention & control , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/adverse effects , COVID-19 Vaccines/immunology , Female , Humans , Male , Middle Aged , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/chemically induced , Purpura, Thrombocytopenic, Idiopathic/epidemiology , Purpura, Thrombocytopenic, Idiopathic/immunology , Retrospective Studies , Risk Factors , SARS-CoV-2/immunology , SARS-CoV-2/metabolism , Splenectomy , United Kingdom/epidemiology
8.
Blood ; 138(22): 2256-2268, 2021 12 02.
Article in English | MEDLINE | ID: covidwho-1443788

ABSTRACT

SARS-CoV-2 vaccine ChAdOx1 nCoV-19 (AstraZeneca) causes a thromboembolic complication termed vaccine-induced immune thrombotic thrombocytopenia (VITT). Using biophysical techniques, mouse models, and analysis of VITT patient samples, we identified determinants of this vaccine-induced adverse reaction. Super-resolution microscopy visualized vaccine components forming antigenic complexes with platelet factor 4 (PF4) on platelet surfaces to which anti-PF4 antibodies obtained from VITT patients bound. PF4/vaccine complex formation was charge-driven and increased by addition of DNA. Proteomics identified substantial amounts of virus production-derived T-REx HEK293 proteins in the ethylenediaminetetraacetic acid (EDTA)-containing vaccine. Injected vaccine increased vascular leakage in mice, leading to systemic dissemination of vaccine components known to stimulate immune responses. Together, PF4/vaccine complex formation and the vaccine-stimulated proinflammatory milieu trigger a pronounced B-cell response that results in the formation of high-avidity anti-PF4 antibodies in VITT patients. The resulting high-titer anti-PF4 antibodies potently activated platelets in the presence of PF4 or DNA and polyphosphate polyanions. Anti-PF4 VITT patient antibodies also stimulated neutrophils to release neutrophil extracellular traps (NETs) in a platelet PF4-dependent manner. Biomarkers of procoagulant NETs were elevated in VITT patient serum, and NETs were visualized in abundance by immunohistochemistry in cerebral vein thrombi obtained from VITT patients. Together, vaccine-induced PF4/adenovirus aggregates and proinflammatory reactions stimulate pathologic anti-PF4 antibody production that drives thrombosis in VITT. The data support a 2-step mechanism underlying VITT that resembles the pathogenesis of (autoimmune) heparin-induced thrombocytopenia.


Subject(s)
Antigen-Antibody Complex/immunology , Autoantibodies/immunology , COVID-19/prevention & control , Capsid Proteins/adverse effects , Drug Contamination , Genetic Vectors/adverse effects , HEK293 Cells/immunology , Immunoglobulin G/immunology , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/etiology , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/adverse effects , Adenoviridae/immunology , Animals , Antigen-Antibody Complex/ultrastructure , Autoantibodies/biosynthesis , Capillary Leak Syndrome/etiology , Capsid Proteins/immunology , Cell Line, Transformed , /immunology , Dynamic Light Scattering , Epitopes/chemistry , Epitopes/immunology , Extracellular Traps/immunology , Extravasation of Diagnostic and Therapeutic Materials/etiology , Genetic Vectors/immunology , HEK293 Cells/chemistry , Humans , Imaging, Three-Dimensional , Immunoglobulin G/biosynthesis , Inflammation , Mice , Microscopy/methods , Platelet Activation , Proteomics , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/immunology , Sinus Thrombosis, Intracranial/diagnostic imaging , Sinus Thrombosis, Intracranial/immunology , Spike Glycoprotein, Coronavirus/immunology , Virus Cultivation
10.
BMC Pregnancy Childbirth ; 21(1): 567, 2021 Aug 18.
Article in English | MEDLINE | ID: covidwho-1365335

ABSTRACT

BACKGROUND: Coronavirus disease 2019 (COVID-19) still is a global emergency. According to the studies, pregnant women are of the at risk populations and any underlying disease(s) might even worsen their condition. The aim of this study is reporting a complex case of immune thrombocytopenic purpura (ITP) during pregnancy who has been diagnosed with COVID-19 as well as suspicion of HELLP syndrome. CASE PRESENTATION: A 24-year-old woman with a platelet count of 6000/mL and resistance to conventional therapies was referred. A day after starting 0.5 g/day of methylprednisolone for her, fever and a decrease in SpO2 presented. According to the paraclinical investigations, COVID-19 was diagnosed and the conventional COVID-19 treatments started for her (the methylprednisolone pulse stopped). Due to the increased liver enzymes and low platelet count, with suspicion of HELLP syndrome, cesarean section surgery was performed which resulted in a healthy neonate. Then, the methylprednisolone pulse was restarted for and she developed an increase in the platelet count. CONCLUSION: It is not clear how COVID-19 and pregnancy affected the patient's condition and the underlying disease; however, it seems the delivery and/or restarting the methylprednisolone pulses caused improvement in her condition.


Subject(s)
COVID-19/diagnosis , Methylprednisolone/administration & dosage , Pregnancy Complications, Hematologic/drug therapy , Pregnancy Complications, Infectious/diagnosis , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Antiviral Agents/therapeutic use , COVID-19/complications , COVID-19/drug therapy , COVID-19/virology , Cesarean Section , Drug Resistance , Female , HELLP Syndrome/diagnosis , Humans , Infant, Newborn , Male , Platelet Count , Pregnancy , Pregnancy Complications, Hematologic/blood , Pregnancy Complications, Hematologic/diagnosis , Pregnancy Complications, Infectious/drug therapy , Pregnancy Complications, Infectious/virology , Pulse Therapy, Drug , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/complications , Purpura, Thrombocytopenic, Idiopathic/diagnosis , SARS-CoV-2/isolation & purification , Treatment Outcome , Young Adult
11.
Eur Rev Med Pharmacol Sci ; 25(15): 5063-5069, 2021 08.
Article in English | MEDLINE | ID: covidwho-1346861

ABSTRACT

OBJECTIVE: Vaccine-induced immune thrombocytopenia (VITT) is a new syndrome occurring primarily in healthy young adults, with a female predominance, after receiving the first dose of ChAdOx1 nCoV-19 vaccine. We describe VITT syndrome characterized by severe thrombosis and thrombocytopenia found in our patient, with fatal outcome. CASE REPORT: A 58-year-old man, after 13 days from the first administration of ChAdOx1 nCoV-19 vaccine (AstraZeneca), presented with abdominal pain, diarrhea and vomitus. Laboratory tests revealed a severe thrombocytopenia, low fibrinogen serum levels and marked increase of D-dimer serum levels. The patient quickly developed a multiple organ failure, till death, three days after the hospital admission. RESULTS: At histology, in the lungs, interalveolar septa appeared thickened with microthrombi in the capillaries and veins. Interalveolar septa appeared thickened and showed vascular proliferation. Thrombi were detected in the capillaries of glomerular tufts. In the hearth, thrombi were observed in veins and capillaries. In the liver, voluminous fibrin thrombi were diffusely observed in the branches of the portal vein. Microthrombi were also found in the vasa vasorum of the wall of abdominal aorta. In the brain, microthrombi were observed in the capillaries of the choroid plexuses. Diffuse hemorrhagic necrosis was observed in the intestinal wall with marked congestion of the venous vessels. CONCLUSIONS: In our patient, the majority of data necessary for a VITT final diagnosis were present: thrombocytopenia and thrombosis in pulmonary, portal, hepatic, renal and mesenteric veins, associated with a marked increase of D-dimer serum levels. The finding of cerebral thrombosis in choroid plexuses, is a new finding in VITT. These features are suggestive for a very aggressive form of VITT.


Subject(s)
COVID-19 Vaccines/adverse effects , COVID-19/prevention & control , Purpura, Thrombocytopenic, Idiopathic/etiology , Thrombosis/etiology , Aorta/pathology , COVID-19/blood , COVID-19 Vaccines/administration & dosage , Choroid Plexus/pathology , Fibrin Fibrinogen Degradation Products/metabolism , Humans , Ileum/pathology , Kidney/pathology , Liver/pathology , Lung/pathology , Male , Middle Aged , Myocardium/pathology , Purpura, Thrombocytopenic, Idiopathic/blood , Thrombosis/blood
12.
Thromb Haemost ; 121(12): 1622-1627, 2021 Dec.
Article in English | MEDLINE | ID: covidwho-1334018

ABSTRACT

BACKGROUND: Coronavirus disease 2019 vaccine ChAdOx1 nCov-19 may rarely lead to vaccine-induced thrombotic thrombocytopenia (VITT). Antibody-mediated, platelet factor 4 (PF4)-dependent platelet activation appears to resemble a key mechanism in VITT, partially comparable to heparin-induced thrombocytopenia. The use of PF4/heparin immunoassays has been proposed as part of a diagnostic approach, but their sensitivity has not been established. METHODS: Sera from 12 well-defined VITT patients were first studied by two different laboratories in functional assays. Sera where then used for an interlaboratory comparison, in which five different PF4/heparin immunoassays were used by four laboratories. RESULTS: Results for functional testing were highly concordant. VITT antibodies were also reliably detected by PF4/heparin enzyme-linked immunosorbent assays (ELISAs) (92-100%). In contrast, only 25% of VITT antibodies were reactive in a particle gel immunoassay (PaGIA), and 8% in a lateral flow assay (LFA). An automated chemiluminescence immunoassay (CLIA) was negative for all sera tested (0%). CONCLUSION: It seems feasible to establish functional antibody testing for the confirmation of VITT. For the initial screening of suspected VITT cases, PaGIA, LFA, and CLIA are useless when applied as single tests. Only ELISA-based PF4/heparin immunoassays are sensitive enough to be incorporated in the diagnostic workup. However, a combination of a positive ELISA and a negative CLIA may be useful to identify VITT antibodies in the absence of confirmatory functional assays.


Subject(s)
Antibodies/blood , Enzyme-Linked Immunosorbent Assay , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/diagnosis , Vaccination/adverse effects , Biomarkers/blood , Humans , Luminescent Measurements , Predictive Value of Tests , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/chemically induced , Purpura, Thrombocytopenic, Idiopathic/immunology , Reproducibility of Results
14.
Blood ; 138(14): 1269-1277, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1317119

ABSTRACT

Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a severe adverse effect of ChAdOx1 nCoV-19 COVID-19 vaccine (Vaxzevria) and Janssen Ad26.COV2.S COVID-19 vaccine, and it is associated with unusual thrombosis. VITT is caused by anti-platelet factor 4 (PF4) antibodies activating platelets through their FcγRIIa receptors. Antibodies that activate platelets through FcγRIIa receptors have also been identified in patients with COVID-19. These findings raise concern that vaccination-induced antibodies against anti-SARS-CoV-2 spike protein cause thrombosis by cross-reacting with PF4. Immunogenic epitopes of PF4 and SARS-CoV-2 spike protein were compared using in silico prediction tools and 3D modeling. The SARS-CoV-2 spike protein and PF4 share at least 1 similar epitope. Reactivity of purified anti-PF4 antibodies from patients with VITT was tested against recombinant SARS-CoV-2 spike protein. However, none of the affinity-purified anti-PF4 antibodies from 14 patients with VITT cross-reacted with SARS-CoV-2 spike protein. Sera from 222 polymerase chain reaction-confirmed patients with COVID-19 from 5 European centers were tested by PF4-heparin enzyme-linked immunosorbent assays and PF4-dependent platelet activation assays. We found anti-PF4 antibodies in sera from 19 (8.6%) of 222 patients with COVID-19. However, only 4 showed weak to moderate platelet activation in the presence of PF4, and none of those patients developed thrombotic complications. Among 10 (4.5%) of 222 patients who had COVID-19 with thrombosis, none showed PF4-dependent platelet-activating antibodies. In conclusion, antibodies against PF4 induced by vaccination do not cross-react with the SARS-CoV-2 spike protein, indicating that the intended vaccine-induced immune response against SARS-CoV-2 spike protein is not the trigger of VITT. PF4-reactive antibodies found in patients with COVID-19 in this study were not associated with thrombotic complications.


Subject(s)
Antibodies/adverse effects , COVID-19 Vaccines/adverse effects , Cross Reactions/immunology , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/etiology , Purpura, Thrombocytopenic, Idiopathic/immunology , Spike Glycoprotein, Coronavirus/immunology , Adult , Aged , Aged, 80 and over , Blood Platelets/immunology , COVID-19/immunology , Cohort Studies , Epitopes/immunology , Female , Heparin/metabolism , Humans , Immunoglobulin G/immunology , Male , Middle Aged , Protein Binding , Protein Domains , Purpura, Thrombocytopenic, Idiopathic/blood , Spike Glycoprotein, Coronavirus/chemistry , Young Adult
16.
Sci Prog ; 104(2): 368504211025927, 2021.
Article in English | MEDLINE | ID: covidwho-1268172

ABSTRACT

With over 600 million coronavirus (COVID-19) vaccine doses administered globally, adverse events are constantly monitored. Recently however, reports of thrombosis and thrombocytopenia following vaccination with the ChAdOx1 nCoV-19 vaccine have emerged. This paper aims to review the available literature and guidelines pertaining to vaccine-induced immune thrombotic thrombocytopenia (VITT) and the proposed guidelines, while offering a potential approach that unifies the available evidence. While the risk of VITT remains extremely low and the benefits outweigh the risks, experimental studies are needed to clarify the pathophysiology behind VITT and possibly decrease the risk of thrombosis and other adverse events occurring. However, treatment should not be delayed in suspected cases, and IV immunoglobulin and non-heparin anticoagulation should be initiated.


Subject(s)
Anticoagulants/therapeutic use , COVID-19 Vaccines/adverse effects , COVID-19/prevention & control , Immunoglobulins, Intravenous/therapeutic use , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Thrombosis/drug therapy , Antithrombins/therapeutic use , Autoantibodies/blood , Biomarkers/blood , COVID-19/epidemiology , COVID-19/immunology , Factor Xa Inhibitors/therapeutic use , Fibrin Fibrinogen Degradation Products/metabolism , Fondaparinux/therapeutic use , Heparin/adverse effects , Humans , Practice Guidelines as Topic , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/chemically induced , Purpura, Thrombocytopenic, Idiopathic/pathology , SARS-CoV-2/immunology , SARS-CoV-2/pathogenicity , Thrombosis/blood , Thrombosis/chemically induced , Thrombosis/pathology
17.
Pediatr Hematol Oncol ; 38(7): 663-668, 2021 Oct.
Article in English | MEDLINE | ID: covidwho-1216504

ABSTRACT

Patients with coronavirus disease 2019 (COVID-19) from novel coronavirus (SARS-CoV-2) infection may present with immune thrombocytopenia (ITP). Multisystem inflammatory syndrome in children (MIS-C) is a serious complication of SARS-CoV-2 causing systemic organ dysfunction. This case series presents the first reported cases of patients who developed ITP following MIS-C, while completing corticosteroid tapers. These patients responded to standard of care therapies for ITP and had appropriate platelet count recovery. We emphasize the importance of careful monitoring of those recovering from COVID-19 or MIS-C, to proactively identify clinical and laboratory abnormalities, in addition to long-term cardiovascular sequelae.


Subject(s)
COVID-19/complications , Purpura, Thrombocytopenic, Idiopathic/etiology , Systemic Inflammatory Response Syndrome/complications , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Aspirin/therapeutic use , COVID-19/blood , COVID-19/therapy , Child , Disease Management , Glucocorticoids/therapeutic use , Humans , Infant , Male , Methylprednisolone/therapeutic use , Platelet Count , Prednisolone/therapeutic use , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/therapy , Systemic Inflammatory Response Syndrome/blood , Systemic Inflammatory Response Syndrome/therapy
18.
Thromb Haemost ; 121(11): 1395-1399, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1182893

ABSTRACT

A series of cases with rare thromboembolic incidents including cerebral sinus vein thrombosis (some of them fatal) and concomitant thrombocytopenia occurring shortly after vaccination with the coronavirus disease 2019 (COVID-19) vaccine AZD1222 (Vaxzevria) have caused significant concern and led to its temporary suspension in many countries. Immediate laboratory efforts in four of these patients have identified a tentative pathomechanism underlying this syndrome termed initially vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) and renamed recently vaccine-induced immune thrombotic thrombocytopenia (VITT). It encompasses the presence of platelet-activating antibodies to platelet factor-4/heparin complexes, possibly emulated by polyanionic constituents of AZD1222, and thus resembles heparin-induced thrombocytopenia (HIT). Because these immune complexes bind and activate platelets via Fcγ receptor IIA (FcγRIIA), high-dose intravenous immunoglobulin G has been suggested for treatment of VITT in addition to non-heparin anticoagulants. Here we propose inhibitors of Bruton tyrosine kinase (Btk) approved for B cell malignancies (e.g., ibrutinib) as another therapeutic option in VITT, as they are expected to pleiotropically target multiple pathways downstream of FcγRIIA-mediated Btk activation, for example, as demonstrated for the effective inhibition of platelet aggregation, dense granule secretion, P-selectin expression and platelet-neutrophil aggregate formation stimulated by FcγRIIA cross-linking. Moreover, C-type lectin-like receptor CLEC-2- and GPIb-mediated platelet activation, the interactions and activation of monocytes and the release of neutrophil extracellular traps, as encountered in HIT, could be attenuated by Btk inhibitors. As a paradigm for emergency repurposing of approved drugs in COVID-19, off-label use of Btk inhibitors in a low-dose range not affecting haemostatic functions could thus be considered a sufficiently safe option to treat VITT.


Subject(s)
Agammaglobulinaemia Tyrosine Kinase/antagonists & inhibitors , Blood Platelets/drug effects , COVID-19 Vaccines/adverse effects , Platelet Activation/drug effects , Protein Kinase Inhibitors/therapeutic use , Purpura, Thrombocytopenic, Idiopathic/drug therapy , Vaccination/adverse effects , Agammaglobulinaemia Tyrosine Kinase/metabolism , Animals , Autoantibodies/blood , Blood Platelets/enzymology , Blood Platelets/immunology , COVID-19 Vaccines/administration & dosage , Humans , Molecular Targeted Therapy , Platelet Factor 4/immunology , Purpura, Thrombocytopenic, Idiopathic/blood , Purpura, Thrombocytopenic, Idiopathic/enzymology , Purpura, Thrombocytopenic, Idiopathic/immunology , Receptors, IgG/metabolism , Signal Transduction
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