OC 44.2 - Developing humanized mouse models as a testing platform for immune tolerance induction therapy for antibody-positive hemophilia A patients

Monday, June 26, 2023

15:00 – 15:15 ET

Room: 520

Session Available As: On-Demand

Presenting Author(s)

Li-Fu Chen

Master student
Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)

Co-Author(s)

Sheng-Chieh Chou, MD. (he/him/his)

Hematologist
Division of Hematology, Department of Internal Medicine, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)
YW

Yi-Hsuan Wu

Master student
Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University
Kaohsiung, Kaohsiung, Taiwan (Republic of China)
YC

Yen-Ting Chang

Master student
Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University
Hsinchu, Hsinchu, Taiwan (Republic of China)
CL

Chien-Hong Liu

Research assistant
Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)
CC

Chin-Yu Cheng

Medical laboratory scientist
Department of Laboratory Medicine, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)
BL

Bin-Bin Lin

Medical laboratory scientist
Department of Laboratory Medicine, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)
CH

Cheng-An Hsu

Medical laboratory scientist
Department of Laboratory Medicine, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)
IY

I-Shing Yu

Associate researcher
Laboratory Animal Center; Collage of Medicine, National Taiwan University
Taipei, Taipei, Taiwan (Republic of China)
SL

Shu-Wha Lin

Professor
Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University; Department of Laboratory Medicine, National Taiwan University Hospital
Taipei, Taipei, Taiwan (Republic of China)

Background: Patients with hemophilia A (PwHA) are at risk of developing FVIII inhibitors. Although emicizumab, mimicking FVIII function, can prevent spontaneous bleeding of PwHA with inhibitor, it cannot provide sufficient coagulation function in surgery or major trauma. Thus, immune tolerance induction (ITI) to eradicate factor VIII inhibitor is still clinically relevant. However, ITI can be successful for 70% patients and individualized prediction model is not optimal.

Aims: This research aims to establish and test whether a humanized HA mouse model for transferring PwHA’s immune system can be a good testing platform to provide an individualized ITI prediction model.

Methods: Immunocompetent HA mice with FVIII inhibitors were generated by frequent challenging the mice with FVIII protein (Advate). The PBMC/splenocytes from these inhibitor positive mice were transplanted into GvHD-resistant immunodeficient NSG-HA mice. The inhibitor titers in the NSG-HA recipients were determined by Bethesda assay, and mice with high inhibitor titers were treated with FVIII for testing ITI. Blood was regularly assayed for inhibitor levels, and for FVIII recovery rate and half-life by one-stage clotting assay.

Results: Human FVIII inhibitors can be generated in the immunocompetent HA mice. The averaged titers were 100 BU (0-925 BU, n=16). Of 14 NSG-HA recipient mice transplanted with the PBMC of FVIII-inhibitor mice, 4 give 20-329 BU. ITI were performed on these 4 mice. Three mice showed reduction of FVIII inhibitors to 0-43.3 BU (20.1→1.6 BU, 329.4BU→43.3 BU, 31→0.0 BU; Figure 1 a-c) after ITI for 8 weeks. In the PBMC of NSG-HA recipient mice approximately 20% donor cells were B cells.

Conclusion(s): We have established an ITI testing platform using NSG-HA mice transplanted with the PBMC from high-titer FVIII inhibitor mice. A substantially shortened testing time for decrease of FVIII inhibitors to < 0.6 BU was achieved in ITI for 8 weeks.

Learning Objectives:

Learn the latest immunodeficiency mouse model which prevents graft-versus-host disease (GvHD) from human PBMC transplant, and stably express human cells for more than three months.
Get stable expression of antigen-presenting human B cells in the humanized mouse model, which can be applied to different mouse models to study immune diseases.
Notice a new treatment concept for hemophilia A patients, using a humanized mouse model to simulate the patient's response to immune tolerance induction (ITI) therapy, as a new option for clinical decision-making.