Leydi Carolina Velásquez Pereira1, Elien Roose1, Nuno A G Graça2,3, György Sinkovits4, Kadri Kangro1, Bérangère S Joly5, Edwige Tellier6,7, Gilles Kaplanski6, Tanja Falter8,9, Charis Von Auer9,10, Heidi Rossmann8,9, Hendrik B Feys11,12, Marienn Reti13, Zoltán Prohászka4, Bernhard Lämmle9,14,15, Jan Voorberg2, Paul Coppo16,17, Agnès Veyradier5, Simon F De Meyer1, Andres Männik3, Karen Vanhoorelbeke1. 1. Laboratory for Thrombosis Research, IRF Life Sciences, KU Leuven Campus Kulak Kortrijk, Kortrijk, Belgium. 2. Department of Molecular and Cellular Hemostasis, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands. 3. Icosagen Cell Factory OÜ, Kambia vald, Tartumaa, Estonia. 4. Department of Internal Medicine and Hematology, and Research Group of Immunology and Hematology, Hungarian Academy of Sciences and Semmelweis University, Budapest, Hungary. 5. Service d'Hématologie biologique, Hôpital Lariboisière, Assistance Publique-Hôpitaux de Paris and EA3518, Institut de Recherche Saint Louis, Université de Paris, Paris, France. 6. INSERM, INRAE, C2VN, Aix-Marseille Univ, Marseille, France. 7. APHM, INSERM, C2VN, CHU Conception, Service de Médecine Interne et Immunologie Clinique, Aix-Marseille Univ, Marseille, France. 8. Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center, Johannes Gutenberg University, Mainz, Germany. 9. Center for Thrombosis and Hemostasis, University Medical Center of the Johannes Gutenberg University, Mainz, Germany. 10. Department of Hematology, Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany. 11. Transfusion Research Center, Belgian Red Cross-Flanders, Ghent, Belgium. 12. Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium. 13. Department of Haematology and Stem Cell Transplantation, Central Hospital of Southern Pest, National Institute of Haematology and Infectious Diseases, Budapest, Hungary. 14. Department of Hematology and Central Hematology Laboratory, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. 15. Haemostasis Research Unit, University College London, London, UK. 16. Service d'hématologie, Hôpital Saint-Antoine, Assistance Publique - Hôpitaux de Paris, Paris, France. 17. Université Sorbonne Paris Cité, Paris, France.
Abstract
BACKGROUND: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is caused by anti-ADAMTS13 autoantibodies inducing a severe deficiency of ADAMTS13. Epitope mapping studies on samples obtained during acute iTTP episodes have shown that the iTTP immune response is polyclonal, with almost all patients having autoantibodies targeting the spacer domain of ADAMTS13. OBJECTIVES: To identify the immunogenic hotspots in the spacer domain of ADAMTS13. PATIENTS/ METHODS: A library of 11 full-length ADAMTS13 spacer hybrids was created in which amino acid regions of the spacer domain of ADAMTS13 were exchanged by the corresponding region of the spacer domain of ADAMTS1. Next, the full-length ADAMTS13 spacer hybrids were used in enzyme-linked immunosorbent assay to epitope map anti-spacer autoantibodies in 138 samples from acute and remission iTTP patients. RESULTS: Sixteen different anti-spacer autoantibody profiles were identified with a similar distribution in acute and remission patients. There was no association between the anti-spacer autoantibody profiles and disease severity. Almost all iTTP samples contained anti-spacer autoantibodies against the following three regions: amino acid residues 588-592, 602-610, and 657-666 (hybrids E, G, and M). Between 31% and 57% of the samples had anti-spacer autoantibodies against amino acid regions 572-579, 629-638, 667-676 (hybrids C, J, and N). In contrast, none of the samples had anti-spacer autoantibodies against amino acid regions 556-563, 564-571, 649-656, and 677-685 (hybrids A, B, L, and O). CONCLUSION: We identified three hotspot regions (amino acid regions 588-592, 602-610, and 657-666) in the spacer domain of ADAMTS13 that are targeted by anti-spacer autoantibodies found in a large cohort of iTTP patients.
BACKGROUND: Immune-mediated thrombotic thrombocytopenic purpura (iTTP) is caused by anti-ADAMTS13 autoantibodies inducing a severe deficiency of ADAMTS13. Epitope mapping studies on samples obtained during acute iTTP episodes have shown that the iTTP immune response is polyclonal, with almost all patients having autoantibodies targeting the spacer domain of ADAMTS13. OBJECTIVES: To identify the immunogenic hotspots in the spacer domain of ADAMTS13. PATIENTS/ METHODS: A library of 11 full-length ADAMTS13 spacer hybrids was created in which amino acid regions of the spacer domain of ADAMTS13 were exchanged by the corresponding region of the spacer domain of ADAMTS1. Next, the full-length ADAMTS13 spacer hybrids were used in enzyme-linked immunosorbent assay to epitope map anti-spacer autoantibodies in 138 samples from acute and remission iTTP patients. RESULTS: Sixteen different anti-spacer autoantibody profiles were identified with a similar distribution in acute and remission patients. There was no association between the anti-spacer autoantibody profiles and disease severity. Almost all iTTP samples contained anti-spacer autoantibodies against the following three regions: amino acid residues 588-592, 602-610, and 657-666 (hybrids E, G, and M). Between 31% and 57% of the samples had anti-spacer autoantibodies against amino acid regions 572-579, 629-638, 667-676 (hybrids C, J, and N). In contrast, none of the samples had anti-spacer autoantibodies against amino acid regions 556-563, 564-571, 649-656, and 677-685 (hybrids A, B, L, and O). CONCLUSION: We identified three hotspot regions (amino acid regions 588-592, 602-610, and 657-666) in the spacer domain of ADAMTS13 that are targeted by anti-spacer autoantibodies found in a large cohort of iTTP patients.
Authors: Nuno A G Graça; Bérangère S Joly; Jan Voorberg; Karen Vanhoorelbeke; Nicolas Béranger; Agnès Veyradier; Paul Coppo Journal: Br J Haematol Date: 2022-02-10 Impact factor: 8.615