1
|
Souri M, Osaki T, Shimura Y, Ichikawa S, Mori M, Ogawa Y, Ichinose A. Identification of non-neutralizing anti-factor X autoantibodies in three Japanese cases of autoimmune acquired factor X deficiency. Haemophilia 2023; 29:555-563. [PMID: 36478471 DOI: 10.1111/hae.14711] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Autoimmune factor X (FX or F10) deficiency (AiF10D) is an extremely rare acquired haemorrhagic disorder characterized by a severe reduction in FX activity due to autoantibodies against FX. AIM Anti-FX autoantibodies were investigated in four patients with suspected AiF10D, and their properties were analysed. METHODS AND RESULTS Anti-FX auto antibodies in plasma were detected by ELISA with three of four cases. One case of anti-FX autoantibody negativity was later diagnosed as AL-amyloidosis. IgG1 and IgG3 coexisted in all anti-FX autoantibodies of the three patients with AiF10D (cases X1, X2, and X3). Western blot analysis showed that the antibodies were bound to the FX light chain for cases X2 and X3, but the binding was weak for case X1. When the fusion proteins of a secretory luciferase with full-length FX or its γ-carboxylated glutamic acid (Gla) domain were added to the plasma of the three patients, both fusion proteins were immunoprecipitated as antigen-antibody complexes. Contrarily, the latter fusion protein produced in the presence of warfarin demonstrated a decrease in the collection rate, suggesting that their autoantibodies recognized the light chain and regions containing Gla residues. Since all three patients were essentially negative for FX inhibitors, it was concluded that the anti-FX autoantibodies for these cases were predominantly non-neutralizing. The concentration of the FX antigen also significantly reduced in these patients, suggesting that anti-FX autoantibodies promote the clearance of FX. CONCLUSION Immunological anti-FX autoantibody detection is highly recommended to ensure that AiF10D cases are not overlooked, and to start necessary immunosuppressive therapies.
Collapse
Affiliation(s)
- Masayoshi Souri
- Department of Molecular Patho-Biochemistry and Patho-Biology, Yamagata University School of Medicine, Yamagata, Japan.,Japanese Collaborative Research Group on Autoimmune Coagulation Factor Deficiency supported by the Japanese Ministry of Health, Labor and Welfare, Yamagata, Japan.,Department of Public Health and Hygiene, Yamagata University School of Medicine, Yamagata, Japan
| | - Tsukasa Osaki
- Department of Molecular Patho-Biochemistry and Patho-Biology, Yamagata University School of Medicine, Yamagata, Japan.,Japanese Collaborative Research Group on Autoimmune Coagulation Factor Deficiency supported by the Japanese Ministry of Health, Labor and Welfare, Yamagata, Japan.,Department of Public Health and Hygiene, Yamagata University School of Medicine, Yamagata, Japan
| | - Yuji Shimura
- Division of Hematology and Oncology, Department of Medicine, Kyoto Prefectural University of Medicine, Kyoto, Kyoto, Japan
| | | | - Makiko Mori
- Department of Clinical Laboratory, Toyama Prefectural Central Hospital, Toyama, Japan
| | - Yoshiyuki Ogawa
- Japanese Collaborative Research Group on Autoimmune Coagulation Factor Deficiency supported by the Japanese Ministry of Health, Labor and Welfare, Yamagata, Japan.,Department of Hematology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Akitada Ichinose
- Department of Molecular Patho-Biochemistry and Patho-Biology, Yamagata University School of Medicine, Yamagata, Japan.,Japanese Collaborative Research Group on Autoimmune Coagulation Factor Deficiency supported by the Japanese Ministry of Health, Labor and Welfare, Yamagata, Japan
| |
Collapse
|