Cloning of human anti-factor XIII monoclonal antibody dissects mechanisms of polyclonal antibodies in a single patient

Masayoshi Souri, Tatsuhiko Ozawa, Tsukasa Osaki, Takatoshi Koyama, Atsushi Muraguchi, Akitada Ichinose*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Background: Coagulation factor XIII (FXIII) consists of 2 A (FXIII-A) and 2 B (FXIII-B) subunits that cross-link and strengthen the hemostatic fibrin thrombus; thus, abnormal bleeding occurs when FXIII is significantly reduced. Autoimmune-acquired FXIII deficiency (AiF13D) is characterized by lethal bleeding secondary to the development of autoantibodies against FXIII. However, since anti-FXIII autoantibodies are polyclonal, the mechanism underlying FXIII dysfunction is unclear. Objectives: The objective of this study was to dissect the inhibitory mechanisms of polyclonal anti-FXIII autoantibodies. Methods: In this study, we prepared the human monoclonal antibodies (hmAbs) from the peripheral blood of an 86-year-old man with AiF13D by using a new complementary DNA cloning method and analyzed the properties of each autoantibody. Results: Seventeen clones obtained from hmAbs were divided into the following 3 groups: dissociation inhibitors of FXIII-A2B2 (6 clones), assembly inhibitors of FXIII-A2B2 (3 clones), and nonneutralizing/inhibitory hmAbs (8 clones). Dissociation inhibitors strongly inhibited fibrin cross-linking and amine incorporation. Assembly inhibitors extracted FXIII-A from FXIII-A2B2, strongly inhibited binding of FXIII-A to FXIII-B, and activation peptide cleavage. However, the patient's plasma presented a strong inhibition of A2B2 heterodimer assembly but only a slight inhibition of thrombin-Ca2+-dependent dissociation, suggesting that the assembly inhibitors concealed the effect of dissociation inhibitors in plasma. By contrast, nonneutralizing antibodies had little effect on the function of FXIII, suggesting that nonneutralizing hmAbs (and/or dissociation inhibitors and/or assembly inhibitors) promoted the clearance of FXIII-A from the blood. Conclusion: Cloning of anti-FXIII autoantibodies enabled us to not only elucidate the mechanism and pathophysiology of AiF13D but also develop a completely new type of anticoagulant.

Original languageEnglish
Pages (from-to)255-268
Number of pages14
JournalJournal of Thrombosis and Haemostasis
Volume21
Issue number2
DOIs
StatePublished - 2023/02

Keywords

  • acquired bleeding disorder
  • autoimmune coagulation factor deficiency
  • human monoclonal antibody
  • neutralizing antibody
  • nonneutralizing antibody

ASJC Scopus subject areas

  • Hematology

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