Case Report
Split Viewer
Blood Res 2013; 48(1):
Published online March 31, 2013
https://doi.org/10.5045/br.2013.48.1.58
© The Korean Society of Hematology
Characterization of anti-factor VIII antibody in a patient with acquired hemophilia A
1Department of Internal Medicine, CHA University School of Medicine, Seongnam, Korea.
2Department of Laboratory Medicine, CHA University School of Medicine, Seongnam, Korea.
3Department of Pediatrics, Nara Medical University School of Medicine, Nara, Japan.
Correspondence to : Correspondence to Doyeun Oh, M.D., Ph.D. Department of Internal Medicine, CHA Bundang Medical Center and CHA University, Yatapro-59, Bundang-gu, Seongnam 463-712, Korea. Tel: +82-31-780-5217, Fax: +82-31-780-5208, doh@cha.ac.kr
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Acquired hemophilia A (AHA) is a bleeding disorder caused by the development of an auto-antibody against endogenous factor VIII (FVIII). In this study, the epitope of the autoantibody was identified in a 67-year-old female patient with AHA. A prolonged activated partial thromboplastin time (77.4 s) that failed to correct in an incubation mixing test (68.2 s), a decreased FVIII activity, and a high FVIII inhibitor (14.6 Bethesda units/mL) were observed. Enzyme-linked immunosorbent assay demonstrated that the antibody belonged to the immunoglobulin G4 subclass. An immunoblotting assay revealed the light chain (A3/C1/C2 domain) of FVIII as the binding region of the antibody. The bleeding experienced by our patient resulted from the interference of FVIII binding to both FIX by anti-A3 antibodies and phospholipids and von Willebrand factor by anti-C2 antibodies. To the best of our knowledge, this is the first study in Korea characterizing an autoantibody in the context of AHA.
Keywords Acquired hemophilia A, Factor VIII autoantibody, Epitope
PDF
Standard view
Export citation
Share Article
Case Report
Blood Res 2013; 48(1): 58-62
Published online March 31, 2013 https://doi.org/10.5045/br.2013.48.1.58
Copyright © The Korean Society of Hematology.
Characterization of anti-factor VIII antibody in a patient with acquired hemophilia A
Jisu Oh1, Yeongmin Lim1, Moon Ju Jang1, Ji Young Huh2, Midori Shima3*, and Doyeun Oh1*
1Department of Internal Medicine, CHA University School of Medicine, Seongnam, Korea.
2Department of Laboratory Medicine, CHA University School of Medicine, Seongnam, Korea.
3Department of Pediatrics, Nara Medical University School of Medicine, Nara, Japan.
Correspondence to: Correspondence to Doyeun Oh, M.D., Ph.D. Department of Internal Medicine, CHA Bundang Medical Center and CHA University, Yatapro-59, Bundang-gu, Seongnam 463-712, Korea. Tel: +82-31-780-5217, Fax: +82-31-780-5208, doh@cha.ac.kr
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Acquired hemophilia A (AHA) is a bleeding disorder caused by the development of an auto-antibody against endogenous factor VIII (FVIII). In this study, the epitope of the autoantibody was identified in a 67-year-old female patient with AHA. A prolonged activated partial thromboplastin time (77.4 s) that failed to correct in an incubation mixing test (68.2 s), a decreased FVIII activity, and a high FVIII inhibitor (14.6 Bethesda units/mL) were observed. Enzyme-linked immunosorbent assay demonstrated that the antibody belonged to the immunoglobulin G4 subclass. An immunoblotting assay revealed the light chain (A3/C1/C2 domain) of FVIII as the binding region of the antibody. The bleeding experienced by our patient resulted from the interference of FVIII binding to both FIX by anti-A3 antibodies and phospholipids and von Willebrand factor by anti-C2 antibodies. To the best of our knowledge, this is the first study in Korea characterizing an autoantibody in the context of AHA.
Keywords: Acquired hemophilia A, Factor VIII autoantibody, Epitope
Fig 1.
Download
Clinical course of our patient. This graph shows FVIII (%), aPTT (s), and FVIII Ab (BU, Bethesda unit) levels. Abbreviations: rFVIIa, recombinant activated factor VII; Pd, prednisolone; Aza, azathioprine; HD, hospital day.
Fig 2.
Download
The APTT waveform analysis of the patient's plasma. Minor hemostatic effect by infusion. Abbreviations: Patient Pre, Pre-treatment; Patient Post, Post-treatment; NP, normal pooled plasma; Coag, coagulation.
Fig 3.
Download
Immunoblotting assay. Lane No.1 shows an 80-kDa immune complex band (indicating that the antibody against a light chain of FVIII exists in the patient's serum). Lane No.2 shows a cleaved 72-kDa band after activation by thrombin.
Fig 4.
Download
Structure of factor VIII and reported epitopes of factor VIII inhibitors. Epitope regions are indicated by arrows. In this case, the dominant IgG subclass is IgG4, and the binding region is the 72-kDa A3/C1/C2 domain of the light chain. FIXa and FXa indicate activated factor IX and X, respectively. Abbreviations: VWF, von Willebrand factor; APC, activated protein C.
-
Table 1 . Cases of acquired hemophilia A reported in the Korean journals..
Abbreviations: M, male; F, female; F VIII, factor 8; IVIG, intravenous immunoglobulin..
Previous Article
Article Tools
Stats or Metrics
Share this article on
Related articles in BR
-
Two Cases of Acquired Hemophilia A Successfully Treated with Oral Steroid or Danazol
Sun Young Park, Jin Seok Kim, Yuri Kim, In Hae Park, June, Won Cheong, Seung Tae Lee, Jee Sook Hahn, Yoo Hong Min
Korean J Hematol 2005; 40(1): 58-62
