Abstract
Thromboembolic complication is common in severe coronavirus disease 2019 (COVID-19), leading to an investigation into the presence of prothrombotic antibodies akin to those found in heparin-induced thrombocytopenia (HIT). In a study of samples from 130 hospitalized patients, collected 3.6 days after COVID-19 diagnosis, 80% had immunoglobulin G (IgG) antibodies recognizing complexes of heparin and platelet factor 4 (PF4; PF4/H), and 41% had antibodies inducing PF4-dependent P-selectin expression in CpG oligodeoxynucleotide–treated normal platelets. Unlike HIT, both PF4/H-reactive and platelet-activating antibodies were found in patients with COVID-19 regardless of recent heparin exposure. Notably, PF4/H-reactive IgG antibodies correlated with those targeting the receptor-binding domain (RBD) of the severe acute respiratory syndrome coronavirus 2 spike protein. Moreover, introducing exogenous RBD to or removing RBD-reactive IgG from COVID-19 plasma or IgG purified from COVID-19 plasma significantly reduced their ability to activate platelets. RBD-specific antibodies capable of platelet activation were cloned from peripheral blood B cells of patients with COVID-19. These antibodies possessed sequence motifs in the heavy-chain complementarity-determining region 3 (HCDR3), resembling those identified in pathogenic HIT antibodies. Furthermore, IgG+ B cells having these HCDR3 signatures were markedly expanded in patients with severe COVID-19. Importantly, platelet-activating antibodies present in patients with COVID-19 were associated with a specific elevation of platelet α-granule proteins in the plasma and showed a positive correlation with markers for inflammation and tissue damage, suggesting a functionality of these antibodies in patients. The demonstration of functional and structural similarities between certain RBD-specific antibodies in patients with COVID-19 and pathogenic antibodies typical of HIT suggests a novel mechanism by which RBD-specific antibodies might contribute to thrombosis in COVID-19.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 635-647 |
| Number of pages | 13 |
| Journal | Blood |
| Volume | 145 |
| Issue number | 6 |
| DOIs | |
| State | Published - Feb 6 2025 |
Funding
The authors thank Patrick Wilson (University of Chicago) for helping to establish the single B-cell polymerase chain reaction and expression cloning system and Trudy Holyst and Benedetta Bonacci (Versiti Blood Research In statute) for excellent technical support. The work was supported by the National Institutes of Health (NIH), National Heart, Lung, and Blood Institute (NHLBI) (grants HL148120 and HL161127 [R.W.], HL167668 [R.W. Demin W.], HL130724 [Demin W.], and HL158932 [A.P.]); the NIH, Clinical and Translational Science Institute (grant UL1TR001436 [R.W.]); the NIH, NHLBI, Accelerating COVID-19 Therapeutic Interventions and Vaccines-4 (grant 1OT2HL156812 [L.B.K. R.W.]); the NIH, National Institute of Allergy and Infectious Diseases (grants AI079087 [Demin W.] and AI159536 [C.W.]); Versiti Blood Center Research Foundation (R.W. Demin W.); the American Heart Association (grant 20PRE35210461 [W.Z.]); Advancing a Healthier Wisconsin Endowment (G.C.W.); and Froedtert Hospital Foundation (M.B.G.). This research was funded, in part, by NIH, NHLBI agreement 1OT2HL156812. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the NIH. Contribution: R.W. designed the study; W.Z. performed all the plasma antibody and the majority of the monoclonal antibody (mAb) analysis and cloned some mAbs; Y. Zheng cloned the majority of the mAbs, performed some of the functional and all the sequence analysis of the mAbs, and performed the B-cell phenotype analysis with the help of J.W. and Y. Zhang; M.Y. performed the B-cell receptor repertoire analysis and Pearson correlation analysis; N.W. and L.Z. performed the plasma protein analysis and non\u2013COVID-19 acute respiratory symptom (ARS) plasma analysis; J.W. cloned and made the recombinant human platelet factor 4 protein; W.Z. Y. Zheng, M.Y. C.N. P.T. and R.J. processed the patient samples and established the sample bank for the COVID-19 study; M.B.G. was in charge of, and P.H. helped with, the convalescent plasma trial of inpatients with COVID-19; M.B.G. provided patient information; L.Z.K. and A.T.F. provided samples from non\u2013COVD-19 patients with ARS; M.Y. and David W. analyzed the B-cell repertoire data; T.G. provided help in the statistical analysis; J.Z. helped with the structural modeling; M.B.G. S.J. G.C.W. W.C. A.P. L.B.K. P.H. R.A. and Demin W. provided valuable input on the manuscript; N.W. generated the visual abstract; and R.W. wrote the manuscript with help from W.Z. Y. Zheng, M.Y. Demin W. S.J. and N.W. The work was supported by National Institutes of Health ( NIH ; grants HL148120 and HL161127 [R.W.]; HL167668 [R.W. and D.W.]; AI079087 and HL130724 [D.W.]), HL CTSI (UL1TR001436 [R.W.]), ACTIV4 (1OT2HL156812 [L.B.K. and R.W.]), Versiti Blood Center Research Foundation (R.W. and D.W.), AHA (20PRE35210461 [W.Z.]), AI159536 (C.W.), HL158932 (A.P.), Advancing a Healthier Wisconsin Endowment (G.C.W.), and Froedtert Hospital Foundation (M.B.G.). This research was, in part, funded by the NIH Agreement (1OT2HL156812).
ASJC Scopus subject areas
- Biochemistry
- Immunology
- Hematology
- Cell Biology
