1
|
Aleman M, Arepally GM, Baglin T, Buitrago L, Davizon-Castillo P, Dayal S, Flick MJ, Gerber G, Hisada Y, Kolev K, O’Loghlen A, Rezaie AR, Sparkenbaugh EM, Stavrou EX, Ünlü B, Vercellotti GM. Coagulation and platelet biology at the intersection of health and disease: illustrated capsules of the 11th Symposium on Hemostasis at the University of North Carolina. Res Pract Thromb Haemost 2024; 8:102395. [PMID: 38699410 PMCID: PMC11063502 DOI: 10.1016/j.rpth.2024.102395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/05/2024] [Accepted: 02/13/2024] [Indexed: 05/05/2024] Open
Abstract
The University of North Carolina Symposia on Hemostasis began in 2002, with The First Symposium on Hemostasis with a Special Focus on FVIIa and Tissue Factor. They have occurred biannually since and have maintained the primary goal of establishing a forum for the sharing of outstanding advances made in the basic sciences of hemostasis. The 2024 11th Symposium on Hemostasis will bring together leading scientists from around the globe to present and discuss the latest research related to coagulation factors and platelet biology. In keeping with the tradition of the conference, we expect novel cross-disciplinary collaborations to result from bringing together fundamental scientists and physician-scientists from different backgrounds and perspectives. The aim of these collaborations is to springboard the next generation of important advances in the field. This year's program was designed to discuss Coagulation and Platelet Biology at the Intersection of Health and Disease. The goal is to develop a better understanding of the pathophysiologic mechanisms leading to hemostatic and thrombotic disorders as this understanding is critical for the continued development of safe and efficacious therapeutics. Included in this review article are illustrated capsules provided by our speakers that highlight the main conclusions of the invited talks.
Collapse
Affiliation(s)
- Maria Aleman
- Blood Research Center, Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Gowthami M. Arepally
- Division of Hematology, Duke University Medical Center, Durham, North Carolina, USA
| | - Trevor Baglin
- Centessa Pharmaceuticals plc, Cheshire, United Kingdom
| | - Lorena Buitrago
- Allen and Frances Adler Laboratory of Blood and Vascular Biology, Rockefeller University, New York, New York, USA
| | - Pavel Davizon-Castillo
- Department of Pediatrics Hematology/Oncology and Bone Marrow Transplantation, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Sanjana Dayal
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Matthew J. Flick
- Blood Research Center, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Gloria Gerber
- Division of Hematology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Yohei Hisada
- Blood Research Center, Division of Hematology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Krasimir Kolev
- Department of Biochemistry, Institute of Biochemistry and Molecular Biology, Semmelweis University, Budapest, Hungary
| | - Ana O’Loghlen
- Epigenetics & Cellular Senescence Group, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Alireza R. Rezaie
- Department of Biochemistry and Molecular Biology, Cardiovascular Biology Research Program, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, USA
| | - Erica M. Sparkenbaugh
- Blood Research Center, Department of Pathology and Laboratory Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Blood Research Center, Division of Hematology, Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Evi X. Stavrou
- Department of Medicine, Hematology and Oncology Division, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Medicine Service, Section of Hematology-Oncology, Louise Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Betül Ünlü
- Einthoven Laboratory for Experimental Vascular Medicine, Department of Internal Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | | |
Collapse
|
2
|
Xu X, Herdendorf TJ, Duan H, Rohlik DL, Roy S, Zhou H, Alkhateeb H, Khandelwal S, Zhou Q, Li P, Arepally GM, Walker JK, Garcia BL, Geisbrecht BV. Inhibition of the C1s Protease and the Classical Complement Pathway by 6-(4-Phenylpiperazin-1-yl)Pyridine-3-Carboximidamide and Chemical Analogs. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2024; 212:689-701. [PMID: 38149922 PMCID: PMC10872613 DOI: 10.4049/jimmunol.2300630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 12/05/2023] [Indexed: 12/28/2023]
Abstract
The classical pathway (CP) is a potent mechanism for initiating complement activity and is a driver of pathology in many complement-mediated diseases. The CP is initiated via activation of complement component C1, which consists of the pattern recognition molecule C1q bound to a tetrameric assembly of proteases C1r and C1s. Enzymatically active C1s provides the catalytic basis for cleavage of the downstream CP components, C4 and C2, and is therefore an attractive target for therapeutic intervention in CP-driven diseases. Although an anti-C1s mAb has been Food and Drug Administration approved, identifying small-molecule C1s inhibitors remains a priority. In this study, we describe 6-(4-phenylpiperazin-1-yl)pyridine-3-carboximidamide (A1) as a selective, competitive inhibitor of C1s. A1 was identified through a virtual screen for small molecules that interact with the C1s substrate recognition site. Subsequent functional studies revealed that A1 dose-dependently inhibits CP activation by heparin-induced immune complexes, CP-driven lysis of Ab-sensitized sheep erythrocytes, CP activation in a pathway-specific ELISA, and cleavage of C2 by C1s. Biochemical experiments demonstrated that A1 binds directly to C1s with a Kd of ∼9.8 μM and competitively inhibits its activity with an inhibition constant (Ki) of ∼5.8 μM. A 1.8-Å-resolution crystal structure revealed the physical basis for C1s inhibition by A1 and provided information on the structure-activity relationship of the A1 scaffold, which was supported by evaluating a panel of A1 analogs. Taken together, our work identifies A1 as a new class of small-molecule C1s inhibitor and lays the foundation for development of increasingly potent and selective A1 analogs for both research and therapeutic purposes.
Collapse
Affiliation(s)
- Xin Xu
- Department of Biochemistry & Molecular Biophysics, Kansas State University; Manhattan, KS 66506 U.S.A
| | - Timothy J. Herdendorf
- Department of Biochemistry & Molecular Biophysics, Kansas State University; Manhattan, KS 66506 U.S.A
| | - Huiquan Duan
- Department of Biochemistry & Molecular Biophysics, Kansas State University; Manhattan, KS 66506 U.S.A
| | - Denise L. Rohlik
- Department of Microbiology & Immunology, Brody School of Medicine East Carolina University; Greenville, NC 27834 U.S.A
| | - Sourav Roy
- Department of Microbiology & Immunology, Brody School of Medicine East Carolina University; Greenville, NC 27834 U.S.A
| | - Hinman Zhou
- Department of Pharmacology, School of Medicine, St. Louis University; St. Louis, MO 63104 U.S.A
| | - Haya Alkhateeb
- Department of Pharmacology, School of Medicine, St. Louis University; St. Louis, MO 63104 U.S.A
| | - Sanjay Khandelwal
- Division of Hematology, Duke University Medical Center; Durham, NC 27710 U.S.A
| | - Qilong Zhou
- Department of Chemistry, Kansas State University; Manhattan, KS 66506 U.S.A
| | - Ping Li
- Department of Chemistry, Kansas State University; Manhattan, KS 66506 U.S.A
| | | | - John K. Walker
- Department of Pharmacology, School of Medicine, St. Louis University; St. Louis, MO 63104 U.S.A
- Department of Chemistry, St. Louis University; St. Louis, MO 63103 U.S.A
| | - Brandon L. Garcia
- Department of Microbiology & Immunology, Brody School of Medicine East Carolina University; Greenville, NC 27834 U.S.A
| | - Brian V. Geisbrecht
- Department of Biochemistry & Molecular Biophysics, Kansas State University; Manhattan, KS 66506 U.S.A
| |
Collapse
|
3
|
Greinacher A. Thrombotic anti-PF4 immune disorders: HIT, VITT, and beyond. HEMATOLOGY. AMERICAN SOCIETY OF HEMATOLOGY. EDUCATION PROGRAM 2023; 2023:1-10. [PMID: 38066843 PMCID: PMC10727100 DOI: 10.1182/hematology.2023000503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Antibodies against the chemokine platelet factor 4 (PF4) occur often, but only those that activate platelets induce severe prothrombotic disorders with associated thrombocytopenia. Heparin-induced thrombocytopenia (HIT) is the prototypic anti-PF4 disorder, mediated by strong activation of platelets through their FcγIIa (immunoglobulin G [IgG]) receptors (FcγRIIa). Concomitant pancellular activation (monocytes, neutrophils, endothelium) triggers thromboinflammation with a high risk for venous and arterial thrombosis. The classic concept of HIT is that anti-PF4/heparin IgG, recognizing antigen sites on (cationic) PF4 that form in the presence of (anionic) heparin, constitute the heparin-dependent antibodies that cause HIT. Accordingly, HIT is managed by anticoagulation with a nonheparin anticoagulant. In 2021, adenovirus vector COVID-19 vaccines triggered the rare adverse effect "vaccine-induced immune thrombotic thrombocytopenia" (VITT), also caused by anti-PF4 IgG. VITT is a predominantly heparin-independent platelet-activating disorder that requires both therapeutic-dose anticoagulation and inhibition of FcγRIIa-mediated platelet activation by high-dose intravenous immunoglobulin (IVIG). HIT and VITT antibodies bind to different epitopes on PF4; new immunoassays can differentiate between these distinct HIT-like and VITT-like antibodies. These studies indicate that (1) severe, atypical presentations of HIT ("autoimmune HIT") are associated with both HIT-like (heparin-dependent) and VITT-like (heparin-independent) anti-PF4 antibodies; (2) in some patients with severe acute (and sometimes chronic, recurrent) thrombosis, VITT-like antibodies can be identified independent of proximate heparin exposure or vaccination. We propose to classify anti-PF4 antibodies as type 1 (nonpathogenic, non- platelet activating), type 2 (heparin dependent, platelet activating), and type 3 (heparin independent, platelet activating). A key concept is that type 3 antibodies (autoimmune HIT, VITT) require anticoagulation plus an adjunct treatment, namely high-dose IVIG, to deescalate the severe anti-PF4 IgG-mediated hypercoagulability state.
Collapse
Affiliation(s)
- Andreas Greinacher
- Institut für Transfusionsmedizin, Universitätsmedizin Greifswald, Greifswald, Germany
| |
Collapse
|
4
|
Zlamal J, Singh A, Weich K, Jaffal H, Uzun G, Pelzl L, Althaus K, Bakchoul T. Platelet phosphatidylserine is the critical mediator of thrombosis in heparin-induced thrombocytopenia. Haematologica 2023; 108:2690-2702. [PMID: 37102605 PMCID: PMC10542843 DOI: 10.3324/haematol.2022.282275] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 04/19/2023] [Indexed: 04/28/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is a severe immune-mediated prothrombotic disorder caused by antibodies (Ab) reactive to complexes of platelet factor 4 and heparin. Platelets (PLT) and their interaction with different immune cells contribute to prothrombotic conditions in HIT. However, the exact mechanisms and the role of different PLT subpopulations in this prothrombotic environment remain poorly understood. In this study, we observed that HIT patient Ab induce a new PLT population that is characterized by increased P-selectin expression and phosphatidylserine (PS) externalization. Formation of this procoagulant PLT subpopulation was dependent on engagement of PLT Fc-γ-RIIA by HIT Ab and resulted in a significant increase of thrombin generation on the PLT surface. Using an ex vivo thrombosis model and multi-parameter assessment of thrombus formation, we observed that HIT Ab-induced procoagulant PLT propagated formation of large PLT aggregates, leukocyte recruitment and most importantly, fibrin network generation. These prothrombotic conditions were prevented via the upregulation of PLT intracellular cAMP with Iloprost, a clinically approved prostacyclin analogue. Additionally, the functional relevance of P-selectin and PS was dissected. While inhibition of P-selectin did not affect thrombus formation, the specific blockade of PS prevented HIT Ab-mediated thrombin generation and most importantly procoagulant PLT-mediated thrombus formation ex vivo. Taken together, our findings indicate that procoagulant PLT are critical mediators of prothrombotic conditions in HIT. Specific PS targeting could be a promising therapeutic approach to prevent thromboembolic events in HIT patients.
Collapse
Affiliation(s)
- Jan Zlamal
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen, Tübingen, Germany; Centre for Clinical Transfusion Medicine, Tübingen
| | - Anurag Singh
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen, Tübingen
| | - Karoline Weich
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen, Tübingen
| | - Hisham Jaffal
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen, Tübingen
| | - Günalp Uzun
- Centre for Clinical Transfusion Medicine, Tübingen
| | - Lisann Pelzl
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen, Tübingen, Germany; Centre for Clinical Transfusion Medicine, Tübingen
| | - Karina Althaus
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen, Tübingen, Germany; Centre for Clinical Transfusion Medicine, Tübingen
| | - Tamam Bakchoul
- Institute for Clinical and Experimental Transfusion Medicine, Medical Faculty of Tübingen, University of Tübingen, Tübingen, Germany; Centre for Clinical Transfusion Medicine, Tübingen.
| |
Collapse
|
5
|
Renna SA, Zhao X, Kunapuli SP, Ma P, Holinstat M, Boxer MB, Maloney DJ, Michael JV, McKenzie SE. Novel Strategy to Combat the Procoagulant Phenotype in Heparin-Induced Thrombocytopenia Using 12-LOX Inhibition. Arterioscler Thromb Vasc Biol 2023; 43:1808-1817. [PMID: 37345522 DOI: 10.1161/atvbaha.123.319434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 06/13/2023] [Indexed: 06/23/2023]
Abstract
BACKGROUND Heparin-induced thrombocytopenia (HIT) is a major concern for all individuals that undergo cardiac bypass surgeries or require prolonged heparin exposure. HIT is a life- and limb-threatening adverse drug reaction with an immune response following the formation of ultra-large immune complexes that drive platelet activation through the receptor FcγRIIA. Thrombotic events remain high following the standard of care treatment with anticoagulants, while increasing risk of bleeding complications. This study sought to investigate a novel approach to treatment of HIT. Recent reports demonstrate increased procoagulant activity in HIT; however, these reports required analysis ex vivo, and relevance in vivo remains unclear. METHODS Using human and mouse model systems, we investigated the cooperativity of PARs (protease-activated receptors) and FcγRIIA in HIT. We challenged humanized FcγRIIA transgenic mice with or without endogenous mouse Par4 (denoted as IIA-Par4+/+ or IIA-Par4-/-, respectively) with a well-established model IgG immune complex (anti [α]-CD9). Furthermore, we assessed the procoagulant phenotype and efficacy to treat HIT utilizing inhibitor of 12-LOX (12[S]-lipoxygenase), VLX-1005, previously reported to decrease platelet activation downstream of FcγRIIA and PAR4, using the triple allele HIT mouse model. RESULTS IIA-Par4+/+ mice given αCD9 were severely thrombocytopenic, with extensive platelet-fibrin deposition in the lung. In contrast, IIA-Par4-/- mice had negligible thrombocytopenia or pulmonary platelet-fibrin thrombi. We observed that pharmacological inhibition of 12-LOX resulted in a significant reduction in both platelet procoagulant phenotype ex vivo, and thrombocytopenia and thrombosis in our humanized mouse model of HIT in vivo. CONCLUSIONS These data demonstrate for the first time the need for dual platelet receptor (PAR and FcγRIIA) stimulation for fibrin formation in HIT in vivo. These results extend our understanding of HIT pathophysiology and provide a scientific rationale for targeting the procoagulant phenotype as a possible therapeutic strategy in HIT.
Collapse
Affiliation(s)
- Stephanie A Renna
- The Cardeza Foundation for Hematologic Research, Center for Hemostasis, Thrombosis and Vascular Biology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.A.R., X.Z., P.M., J.V.M., S.E.M.)
| | - Xuefei Zhao
- The Cardeza Foundation for Hematologic Research, Center for Hemostasis, Thrombosis and Vascular Biology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.A.R., X.Z., P.M., J.V.M., S.E.M.)
| | - Satya P Kunapuli
- Sol Sherry Thrombosis Center and the Department of Physiology, Temple University School of Medicine, Philadelphia, PA (S.P.K.)
| | - Peisong Ma
- The Cardeza Foundation for Hematologic Research, Center for Hemostasis, Thrombosis and Vascular Biology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.A.R., X.Z., P.M., J.V.M., S.E.M.)
| | - Michael Holinstat
- Department of Pharmacology, University of Michigan, Ann Arbor (M.H.)
| | | | | | - James V Michael
- The Cardeza Foundation for Hematologic Research, Center for Hemostasis, Thrombosis and Vascular Biology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.A.R., X.Z., P.M., J.V.M., S.E.M.)
| | - Steven E McKenzie
- The Cardeza Foundation for Hematologic Research, Center for Hemostasis, Thrombosis and Vascular Biology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA (S.A.R., X.Z., P.M., J.V.M., S.E.M.)
| |
Collapse
|
6
|
Sarkar A, Khandelwal S, Koma GT, Kim H, Gruel Y, Rollin J, Passam F, Wool GD, Arepally GM, Cines DB, Rauova L, Poncz M. Treatment of thrombocytopenia and thrombosis in HIT in mice using deglycosylated KKO: a novel therapeutic? Blood Adv 2023; 7:4112-4123. [PMID: 37196641 PMCID: PMC10388731 DOI: 10.1182/bloodadvances.2023009661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/19/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is characterized by thrombocytopenia associated with a highly prothrombotic state due to the development of pathogenic antibodies that recognize human platelet factor 4 (hPF4) complexed with various polyanions. Although nonheparin anticoagulants are the mainstay of care in HIT, subsequent bleeding may develop, and the risk of developing new thromboembolic events remain. We previously described a mouse immunoglobulin G2bκ (IgG2bκ) antibody KKO that mimics the sentinel features of pathogenic HIT antibodies, including binding to the same neoepitope on hPF4-polyanion complexes. KKO, like HIT IgGs, activates platelets through FcγRIIA and induces complement activation. We then questioned whether Fc-modified KKO could be used as a novel therapeutic to prevent or treat HIT. Using the endoglycosidase EndoS, we created deglycosylated KKO (DGKKO). Although DGKKO retained binding to PF4-polyanion complexes, it inhibited FcγRIIA-dependent activation of PF4-treated platelets triggered by unmodified KKO, 5B9 (another HIT-like monoclonal antibody), and IgGs isolated from patients with HIT. DGKKO also decreased complement activation and deposition of C3c on platelets. Unlike the anticoagulant fondaparinux, injection of DGKKO into HIT mice lacking mouse PF4, but transgenic for hPF4 and FcγRIIA, prevented and reversed thrombocytopenia when injected before or after unmodified KKO, 5B9, or HIT IgG. DGKKO also reversed antibody-induced thrombus growth in HIT mice. In contrast, DGKKO was ineffective in preventing thrombosis induced by IgG from patients with the HIT-related anti-PF4 prothrombotic disorder, vaccine-induced immune thrombotic thrombocytopenia. Thus, DGKKO may represent a new class of therapeutics for targeted treatment of patients with HIT.
Collapse
Affiliation(s)
- Amrita Sarkar
- Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | | | - Gavin T. Koma
- Department of Bioengineering, Temple University, Philadelphia, PA
| | - Hyunjun Kim
- Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Yves Gruel
- Department of Hemostasis, University Hospital Center of Tours, and EA4245 T2i, University of Tours, Tours, France
| | - Jerome Rollin
- Department of Hemostasis, University Hospital Center of Tours, and EA4245 T2i, University of Tours, Tours, France
| | - Freda Passam
- Central Clinical School, Faculty Medicine Health, University of Sydney, Sydney, Australia
| | | | | | - Douglas B. Cines
- Department of Pathology and Clinical Laboratories, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Lubica Rauova
- Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| | - Mortimer Poncz
- Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA
- Department of Pediatrics, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA
| |
Collapse
|
7
|
May J, Westbrook B, Cuker A. Heparin-induced thrombocytopenia: An illustrated review. Res Pract Thromb Haemost 2023; 7:100283. [PMID: 37601013 PMCID: PMC10439402 DOI: 10.1016/j.rpth.2023.100283] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/25/2023] [Accepted: 05/31/2023] [Indexed: 08/22/2023] Open
Abstract
Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse drug effect from unfractionated or low-molecular-weight heparin that results in thrombocytopenia and potentially catastrophic thrombosis. HIT occurs due to the development of platelet-activating antibodies against multimolecular complexes of platelet factor 4 and heparin. Given the frequency of thrombocytopenia and heparin use among hospitalized patients, calculation of the 4Ts Score is recommended to identify patients at increased likelihood of HIT and direct further evaluation. In patients with an intermediate or high probability 4Ts Score, an immunoassay and functional assay are recommended to confirm or refute the diagnosis of HIT. Heparin avoidance and initiation of nonheparin anticoagulation are the mainstays of acute HIT management. In this illustrated review, we provide visual summaries of the diagnosis and management of HIT, highlighting connections between pathophysiology and clinical care as well as summarizing efforts in quality improvement in the field. We further emphasize common pitfalls and pearls in diagnosis and management to encourage evidence-based care. We include graphical representation of the unique challenges of HIT with cardiopulmonary bypass and also delineate autoimmune HIT and its subtypes.
Collapse
Affiliation(s)
- Jori May
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Brian Westbrook
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Adam Cuker
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| |
Collapse
|
8
|
Cai Z, Bdeir K, Yarovoi SV, Rauova L, Arepally GM, Khandelwal S, Rollin J, Gruel Y, Zaitsev S, Poncz M, Greene MI, Cines DB. Modulation of ultralarge immune complexes in heparin-induced thrombocytopenia. J Thromb Haemost 2023; 21:652-666. [PMID: 36696211 DOI: 10.1016/j.jtha.2022.11.043] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 09/21/2022] [Accepted: 11/04/2022] [Indexed: 01/26/2023]
Abstract
BACKGROUND Heparin-induced thrombocytopenia (HIT) is a serious thrombotic disorder caused by ultralarge immune complexes (ULICs) containing platelet factor 4 (PF4) and heparin that form the HIT antigen, together with a subset of anti-PF4 antibodies. ULICs initiate prothrombotic responses by engaging Fcγ receptors on platelets, neutrophils, and monocytes. Contemporary anti-thrombotic therapy for HIT is neither entirely safe nor entirely successful and acts downstream of ULIC formation and Fcγ receptor-initiated generation of thrombin. OBJECTIVES To determine whether HIT antigen and ULIC formation and stability could be modified favorably by inhibiting PF4-heparin interactions with fondaparinux, together with blocking formation of PF4 tetramers using a humanized monoclonal anti-PF4 antibody (hRTO). METHODS Results: The combination of fondaparinux and hRTO inhibited HIT antigen formation, promoted antigen dissociation, inhibited ULIC formation, and promoted ULIC disassembly at concentrations below the effective concentration of either alone and blocked Fcγ receptor-dependent induction of factor Xa activity by monocytic THP1 cells and activation of human platelets in whole blood. Combined with hRTO, fondaparinux inhibited HIT antigen and immune complex formation and activation through Fcγ receptors at concentrations at or below those used clinically to inhibit FXa coagulant activity. CONCLUSIONS HIT antigen and immune complexes are dynamic and amenable to modulation. Fondaparinux can be converted from an anticoagulant that acts at a downstream amplification step into a rationale, disease-specific intervention that blocks ULIC formation. Interventions that prevent ULIC formation and stability might increase the efficacy, permit use of lower doses, shorten the duration of antithrombotic therapy, and help prevent this serious thrombotic disorder.
Collapse
Affiliation(s)
- Zheng Cai
- Department of Pathology and Laboratory Medicine, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Khalil Bdeir
- Department of Pathology and Laboratory Medicine, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Serge V Yarovoi
- Department of Pathology and Laboratory Medicine, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Lubica Rauova
- Children's Hospital of Philadelphia, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Gowthami M Arepally
- Division of Hematology, Duke University Medical Center, Durham, North Carolina, USA
| | - Sanjay Khandelwal
- Division of Hematology, Duke University Medical Center, Durham, North Carolina, USA
| | - Jerome Rollin
- Department of Hemostasis, University of Tours, Tours, France; Centre Hospitalier Régional Universitaire de Tours, Service d'Hémostase, Tours, France
| | - Yves Gruel
- Department of Hemostasis, University of Tours, Tours, France; Centre Hospitalier Régional Universitaire de Tours, Service d'Hémostase, Tours, France
| | - Sergei Zaitsev
- Department of Pathology and Laboratory Medicine, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Mortimer Poncz
- Children's Hospital of Philadelphia, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Mark I Greene
- Department of Pathology and Laboratory Medicine, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA
| | - Douglas B Cines
- Department of Pathology and Laboratory Medicine, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA; Department of Medicine, Perelman-University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA.
| |
Collapse
|
9
|
Selvadurai MV, Favaloro EJ, Chen VM. Mechanisms of Thrombosis in Heparin-Induced Thrombocytopenia and Vaccine-Induced Immune Thrombotic Thrombocytopenia. Semin Thromb Hemost 2023. [PMID: 36706782 DOI: 10.1055/s-0043-1761269] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Heparin-induced thrombocytopenia (HIT) and vaccine-induced immune thrombotic thrombocytopenia (VITT) are rare, iatrogenic immune-mediated conditions with high rates of thrombosis-related morbidity and mortality. HIT is a long-recognized reaction to the administration of the common parenterally administered anticoagulant heparin (or its derivatives), while VITT is a new, distinct syndrome occurring in response to adenovirus-based vaccines against coronavirus disease 2019 and potentially other types of vaccines. A feature of both HIT and VITT is paradoxical thrombosis despite a characteristic low platelet count, mediated by the presence of platelet-activating antibodies to platelet factor 4. Several additional factors have also been suggested to contribute to clot formation in HIT and/or VITT, including monocytes, tissue factor, microparticles, endothelium, the formation of neutrophil extracellular traps, complement, procoagulant platelets, and vaccine components. In this review, we discuss the literature to date regarding mechanisms contributing to thrombosis in both HIT and VITT and explore the pathophysiological similarities and differences between the two conditions.
Collapse
Affiliation(s)
- Maria V Selvadurai
- The Alfred Hospital, Melbourne, VIC, Australia.,ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia
| | - Emmanuel J Favaloro
- Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Sydney Centres for Thrombosis and Haemostasis, NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia.,School of Dentistry and Medical Sciences, Faculty of Science and Health, Charles Sturt University, Wagga Wagga, NSW, Australia.,School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Westmead Hospital, Westmead, NSW, Australia
| | - Vivien M Chen
- ANZAC Research Institute, University of Sydney, Sydney, NSW, Australia.,Department of Haematology, Concord Repatriation General Hospital and NSW Health Pathology, Sydney, NSW, Australia
| |
Collapse
|
10
|
Neutrophils: As a Key Bridge between Inflammation and Thrombosis. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2022; 2022:1151910. [PMID: 36408343 PMCID: PMC9668459 DOI: 10.1155/2022/1151910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/14/2022] [Accepted: 09/29/2022] [Indexed: 11/10/2022]
Abstract
Immunothrombosis is a mechanism of defense of the organism against pathogenic microorganisms that increases their recognition, limitation, and clearance and is part of the innate immune defense. Physiological immunothrombosis is beneficial to the body against the invasion of pathogenic microorganisms, but when immunothrombosis is out of control, it is easy to cause thrombotic diseases, thus, causing unpredictable consequences to the body. Neutrophils play a pivotal role in this process. Understanding the mechanism of neutrophils in immune thrombosis and out-of-control is particularly important for the treatment of related thrombotic diseases. In this review, we studied the role of neutrophils in immune thrombosis and each link out of control (including endothelial cell dysfunction; activation of platelets; activation of coagulation factor; inhibition of the anticoagulation system; and inhibition of the fibrinolysis system).
Collapse
|
11
|
Barnes AP, Khandelwal S, Sartoretto S, Myoung S, Francis SJ, Lee GM, Rauova L, Cines DB, Skare JT, Booth CE, Garcia BL, Arepally GM. Minimal role for the alternative pathway in complement activation by HIT immune complexes. J Thromb Haemost 2022; 20:2656-2665. [PMID: 35996342 PMCID: PMC9938942 DOI: 10.1111/jth.15856] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 07/23/2022] [Accepted: 08/16/2022] [Indexed: 01/19/2023]
Abstract
BACKGROUND Anti-platelet factor 4 (PF4)/heparin immune complexes that cause heparin-induced thrombocytopenia (HIT) activate complement via the classical pathway. Previous studies have shown that the alternative pathway of complement substantially amplifies the classical pathway of complement activation through the C3b feedback cycle. OBJECTIVES These studies sought to examine the contributions of the alternative pathway to complement activation by HIT antibodies. METHODS Using IgG monoclonal (KKO) and/or patient-derived HIT antibodies, we compared the effects of classical pathway (BBK32 and C1-esterase inhibitor [C1-INH]), alternative pathway (anti-factor B [fB] or factor D [fD] inhibitor) or combined classical and alternative pathway inhibition (soluble complement receptor 1 [sCR1]) in whole blood or plasma. RESULTS Classical pathway inhibitors BBK32 and C1-INH and the combined classical/alternative pathway inhibitor sCR1 prevented KKO/HIT immune complex-induced complement activation, including release of C3 and C5 activation products, binding of immune complexes to B cells, and neutrophil activation. The alternative pathway inhibitors fB and fD, however, did not affect complement activation by KKO/HIT immune complexes. Similarly, alternative pathway inhibition had no effect on complement activation by unrelated immune complexes consisting of anti-dinitrophenyl (DNP) antibody and the multivalent DNP--keyhole limpet hemocyanin antigen. CONCLUSIONS Collectively, these findings suggest the alternative pathway contributes little in support of complement activation by HIT immune complexes. Additional in vitro and in vivo studies are required to examine if this property is shared by most IgG-containing immune complexes or if predominance of the classic pathway is limited to immune complexes composed of multivalent antigens.
Collapse
Affiliation(s)
| | | | | | - Sooho Myoung
- Division of Hematology, Duke University Medical Center, Durham, NC
| | | | - Grace M. Lee
- Division of Hematology, Duke University Medical Center, Durham, NC
| | - Lubica Rauova
- Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Douglas B. Cines
- Departments of Pathology and Laboratory Medicine and Medicine, Perelman University of Pennsylvania School of Medicine, Philadelphia, PA
| | - Jon T. Skare
- Department of Microbial Pathogenesis & Immunology, Texas A&M University, College Station, TX
| | - Charles E. Booth
- Department of Microbiology & Immunology, East Carolina University, Greenville, NC
| | - Brandon L. Garcia
- Department of Microbiology & Immunology, East Carolina University, Greenville, NC
| | | |
Collapse
|
12
|
Pryzdial ELG, Leatherdale A, Conway EM. Coagulation and complement: Key innate defense participants in a seamless web. Front Immunol 2022; 13:918775. [PMID: 36016942 PMCID: PMC9398469 DOI: 10.3389/fimmu.2022.918775] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 07/06/2022] [Indexed: 12/30/2022] Open
Abstract
In 1969, Dr. Oscar Ratnoff, a pioneer in delineating the mechanisms by which coagulation is activated and complement is regulated, wrote, “In the study of biological processes, the accumulation of information is often accelerated by a narrow point of view. The fastest way to investigate the body’s defenses against injury is to look individually at such isolated questions as how the blood clots or how complement works. We must constantly remind ourselves that such distinctions are man-made. In life, as in the legal cliché, the devices through which the body protects itself form a seamless web, unwrinkled by our artificialities.” Our aim in this review, is to highlight the critical molecular and cellular interactions between coagulation and complement, and how these two major component proteolytic pathways contribute to the seamless web of innate mechanisms that the body uses to protect itself from injury, invading pathogens and foreign surfaces.
Collapse
Affiliation(s)
- Edward L. G. Pryzdial
- Centre for Blood Research, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Canadian Blood Services, Medical Affairs and Innovation, Vancouver, BC, Canada
- *Correspondence: Edward L. G. Pryzdial, ; Edward M. Conway,
| | - Alexander Leatherdale
- Centre for Blood Research, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
- Division of Hematology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Edward M. Conway
- Centre for Blood Research, Life Sciences Institute, University of British Columbia, Vancouver, BC, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Canadian Blood Services, Medical Affairs and Innovation, Vancouver, BC, Canada
- Division of Hematology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Edward L. G. Pryzdial, ; Edward M. Conway,
| |
Collapse
|
13
|
Platelets get particular. Blood 2022; 140:413-414. [PMID: 35925641 PMCID: PMC9352188 DOI: 10.1182/blood.2022016773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/06/2022] [Indexed: 11/26/2022] Open
|
14
|
Live imaging of platelets and neutrophils during antibody-mediated neurovascular thrombosis. Blood Adv 2022; 6:3697-3702. [PMID: 35452514 PMCID: PMC9040505 DOI: 10.1182/bloodadvances.2021006728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 04/03/2022] [Indexed: 11/20/2022] Open
Abstract
Immune complexes form in systemic disorders such as rheumatological, autoimmune, and allergic diseases, or in response to infections or medications. SARS-CoV-2 adenoviral vector vaccines have been associated with rare, yet serious thrombotic complications in the brain due to the formation of immune complexes that activate platelets. There is currently no data visualizing the interplay of platelets with leukocytes and the brain vasculature endothelium in response to immune complexes. This is in part due to the absence of FcγRIIA in mice, a receptor for immune complexes implicated in these thrombotic incidents. Here, we describe and illustrate events at the cellular level that take place in the brain vasculature in response to systemic administration of surrogate immune complexes. We utilized Ly6gCre+/-::Rosa26-TdT+/-::CD41-YFP+/- mice expressing the FcγRIIA transgene and fluorescence in neutrophils and platelets. Using real-time videomicroscopy to capture high velocity events in conjunction with unbiased computer assisted analyses, we provide images and quantifications of the cellular responses downstream FcγRIIA stimulation. We observed transient and stable platelet-neutrophil interactions, platelets forming thrombi, and neutrophil adhesion to blood vessel walls. This imaging approach in a quadruple transgenic animal model can be utilized for the study of the pathogenic roles of immune complexes in disease.
Collapse
|
15
|
Warkentin TE. Platelet-activating anti-PF4 disorders: an overview. Semin Hematol 2022; 59:59-71. [DOI: 10.1053/j.seminhematol.2022.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 11/11/2022]
|
16
|
Barale C, Melchionda E, Morotti A, Russo I. Prothrombotic Phenotype in COVID-19: Focus on Platelets. Int J Mol Sci 2021; 22:ijms222413638. [PMID: 34948438 PMCID: PMC8705811 DOI: 10.3390/ijms222413638] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 12/15/2022] Open
Abstract
COVID-19 infection is associated with a broad spectrum of presentations, but alveolar capillary microthrombi have been described as a common finding in COVID-19 patients, appearing as a consequence of a severe endothelial injury with endothelial cell membrane disruption. These observations clearly point to the identification of a COVID-19-associated coagulopathy, which may contribute to thrombosis, multi-organ damage, and cause of severity and fatality. One significant finding that emerges in prothrombotic abnormalities observed in COVID-19 patients is that the coagulation alterations are mainly mediated by the activation of platelets and intrinsically related to viral-mediated endothelial inflammation. Beyond the well-known role in hemostasis, the ability of platelets to also release various potent cytokines and chemokines has elevated these small cells from simple cell fragments to crucial modulators in the blood, including their inflammatory functions, that have a large influence on the immune response during infectious disease. Indeed, platelets are involved in the pathogenesis of acute lung injury also by promoting NET formation and affecting vascular permeability. Specifically, the deposition by activated platelets of the chemokine platelet factor 4 at sites of inflammation promotes adhesion of neutrophils on endothelial cells and thrombogenesis, and it seems deeply involved in the phenomenon of vaccine-induced thrombocytopenia and thrombosis. Importantly, the hyperactivated platelet phenotype along with evidence of cytokine storm, high levels of P-selectin, D-dimer, and, on the other hand, decreased levels of fibrinogen, von Willebrand factor, and thrombocytopenia may be considered suitable biomarkers that distinguish the late stage of COVID-19 progression in critically ill patients.
Collapse
Affiliation(s)
| | | | | | - Isabella Russo
- Correspondence: ; Tel.: +39-011-6705447; Fax: +39-011-9038639
| |
Collapse
|
17
|
Pitkänen HH, Jouppila A, Helin T, Dulipati V, Kotimaa J, Meri S, Kantele A, Jalkanen P, Julkunen I, Lassila R. COVID-19 adenovirus vaccine triggers antibodies against PF4 complexes to activate complement and platelets. Thromb Res 2021; 208:129-137. [PMID: 34768097 PMCID: PMC8571998 DOI: 10.1016/j.thromres.2021.10.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/14/2021] [Accepted: 10/28/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND Vaccine-induced thrombotic thrombocytopenia (VITT) is a rare coagulation disorder reported after administration of COVID-19 adenovirus-vectored vaccines. VITT is mediated by anti-platelet factor 4 (PF4) antibodies activating platelets through the Fcγ-receptor II (FcγRII), and it is associated with strong fibrin turnover. The complement system is involved in several other immunothrombotic entities, but its impact on VITT is not established. OBJECTIVE To assess antibodies in interaction with the activation of platelets and complement triggered by VITT. METHODS Antibodies against adenovirus type 2 hexon protein, ChAdOx1 adenoviral vector-specific IgG and PF4 were analyzed by enzyme immunoassays from VITT patients (n = 5). The EDTA plasma samples of the patients and controls were used to measure both terminal complement complexes (TCC) by ELISA and aggregation of healthy donor platelets. We studied the effects of human immunoglobulin (IVIG) and glycoprotein IIb/IIIa inhibitor (GPIIb/IIIa) on spontaneous and collagen-induced platelet aggregation supplemented with VITT plasma. RESULTS None of the patients had experienced a COVID-19 infection. Antibody analyses confirmed the immunogenicity of the adenovirus-vectored ChAdOx1 vaccine. Moreover, VITT plasma had anti-PF4 antibodies and elevated TCC levels as a sign of complement activation. In isolated healthy donor platelets, VITT patient plasma caused marked, spontaneous aggregation of platelets, which was abolished by eptifibatide and high-dose therapeutic IVIG. CONCLUSIONS Our findings suggest that VITT is triggered by antibodies against adenovirus vector and PF4-polyanion complexes which strongly co-activate complement and platelets. The spontaneous platelet aggregation was suppressed by IVIG or eptifibatide, indicating that besides FcγRII, also GPIIb/IIIa receptor exerts platelet procoagulant role in VITT.
Collapse
Affiliation(s)
- Hanna H. Pitkänen
- Helsinki University, Division of Anesthesiology, Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and Helsinki University Hospital, Helsinki, Finland,Clinical Research Institute Helsinki University Hospital, Helsinki, Finland
| | - Annukka Jouppila
- Clinical Research Institute Helsinki University Hospital, Helsinki, Finland
| | - Tuukka Helin
- HUSLAB, Clinical Chemistry, Helsinki University Hospital and University of Helsinki
| | - Vinaya Dulipati
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Finland
| | - Juha Kotimaa
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Finland
| | - Seppo Meri
- Department of Bacteriology and Immunology and Translational Immunology Research Program, University of Helsinki, Finland,HUSLAB, Helsinki University Hospital, Finland
| | - Anu Kantele
- Meilahti Infectious Diseases and Vaccine Research Center, MeVac, Department of Infectious Diseases, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Pinja Jalkanen
- Institute of Biomedicine, University of Turku, Turku, Finland
| | - Ilkka Julkunen
- Institute of Biomedicine, University of Turku, Turku, Finland,Turku University Hospital, Clinical Microbiology, Turku, Finland
| | - Riitta Lassila
- Department of Hematology, Coagulation Disorders Unit, Helsinki University Hospital, Helsinki, Finland,Research Program in Systems Oncology, Faculty of Medicine, University of Helsinki, Finland,Finnish Institute for Health and Welfare, Helsinki, Finland,Corresponding author at: Coagulation Disorders Unit, Department of Hematology and Comprehensive Cancer Center, Laboratory Services, HUCH, PL 372, 00029 Helsinki, Finland
| |
Collapse
|
18
|
Vaccine-induced immune thrombotic thrombocytopenia. LANCET HAEMATOLOGY 2021; 9:e73-e80. [PMID: 34774202 PMCID: PMC8585488 DOI: 10.1016/s2352-3026(21)00306-9] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/12/2021] [Accepted: 09/17/2021] [Indexed: 01/07/2023]
Abstract
In response to the COVID-19 pandemic, vaccines for SARS-CoV-2 were developed, tested, and introduced at a remarkable speed. Although the vaccine introduction had a major impact on the evolution of COVID-19, some potential rare side-effects of the vaccines were observed. Within a short period, three scientific groups from Norway, Germany, and the UK reported cerebral venous sinus thrombosis with thrombocytopenia and anti-platelet factor 4 (anti-PF4) antibodies in individuals following AstraZeneca–Oxford vaccination and named this new syndrome vaccine-induced immune thrombotic thrombocytopenia (VITT). This syndrome was subsequently reported in individuals who received Johnson & Johnson vaccination. In this Viewpoint, we discuss the epidemiology, pathophysiology, and optimal diagnostic and therapeutic management of VITT. Presentation of an individual with possible VITT should raise prompt testing for anti-PF4 antibodies and initiation of treatment targeting autoimmune processes with intravenous immunoglobulin and prothrombotic processes with non-heparin anticoagulation.
Collapse
|