PB0208 - Emicizumab modules human macrophages polarization by binding and activating the Fc gamma receptors

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Co-Author(s)

MR

Mickael Rosa

Assistant professor
CHRU Lille
Lille, Nord-Pas-de-Calais, France
BM

Bruna Mata Soares

Postdoctoral
Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011- EGID, F-59000 Lille, France
59000, Nord-Pas-de-Calais, France
KB

Khalil Ben Hadj Ali

Resident
Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011- EGID, F-59000 Lille, France
59000 Lille, Nord-Pas-de-Calais, France
MD

Melanie Daniel

MD, Fellow
Inserm U1011-EGID, Lille Pasteur Institute, Lille University Hospital
Lille, Nord-Pas-de-Calais, France
CV

Caroline Vayne

PhD
Regional University Hospital Centre Tours, Department of Hemostasis, Tours, France; University of Tours, EA4245, T2i, Tours, France.
Tours, Centre, France
CP

Claire Pouplard

Professor
Regional University Hospital Centre Tours, Department of Hemostasis, Tours, France; University of Tours, EA4245, T2i, Tours, France.
Tours, Centre, France
YG

Yves Gruel

Professor
Regional University Hospital Centre Tours, Department of Hemostasis, Tours, France; University of Tours, EA4245, T2i, Tours, France.
Tours, Pays de la Loire, France
BS

Bart Staels

Head of Unit
Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011- EGID, F-59000 Lille, France
lille, Nord-Pas-de-Calais, France
AR

Antoine Rauch

MD, Professor of Hematology
Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011- EGID, F-59000 Lille, France
Lille, Nord-Pas-de-Calais, France
JR

Jérôme Rollin

Researcher
Inserm UMR1327, University of Tours
Tours, Pays de la Loire, France

Presenting Author(s)

AD

Annabelle Dupont

professor
Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1011-EGID, F5900 Lille
59000 Lille, Nord-Pas-de-Calais, France

Background: Emicizumab is a humanized immunoglobulin G4 approved for bleeding prophylaxis in hemophilia A. By reducing joint bleeding, this treatment prevents synovial membrane inflammation and haemophilic arthropathy. Blood monocytes-derived macrophages play a crucial role in inflammation. These heterogeneous cells can be polarized into M1 (pro-inflammatory) or M2 (anti-inflammatory) phenotype. Some studies shown that IgG4 have a high affinity for the type-I Fc gamma (FcɣRI) receptors expressed on monocytes/macrophages surface. Our hypothesis is that emicizumab modulates monocytes/macrophages phenotype by activating FcɣRI receptors.

Aims: Analyse emicizumab capacity to bind to monocytes, describe the effects of emicizumab on human monocytes/macrophages phenotype and identify involved receptors and signalling pathways.

Methods: Blood monocytes subpopulations distribution was analysed by flow cytometry (CD14/CD16 expression). Emicizumab capacity to bind to monocytes was evaluated by flow cytometry and immunofluorescence microscopy after fluorochrome coupling. Monocytes-derived macrophages phenotype were determined by RT-qPCR. Syk phosphorylation was assessed by Western blot. All blood sample donors signed a consent form

Results: IIn severe hemophilia A patients, no difference of classical, intermediate and non-classical monocytes subsets distribution was observed according to treatment (12 FVIII, 7 emicizumab). Moreover, emicizumab (50µg/mL) binds to 3 mean subsets of monocytes, in significant proportion (Fig.1A) and using FcɣRI, FcɣRII and FcɣRIII receptors blockers, emicizumab only binds to FcɣRI. We also observed that emicizumab induces in monocytes-derived macrophages higher expression of M1 markers (interleukin-1β, interleukin-6, TNFα) but also of M2 markers (mannose receptor, CD200R) associated to lower expression of M2 markers (interleukin-10) (Fig.1B). These results show that emicizumab modulates monocytes differentiation in intermediate M1/M2 macrophages. Finally, Syk phosphorylation was examined in monocytes, revealing higher phosphorylation in cells incubated with emicizumab (50µg/mL) (Fig.2).

Conclusion(s): This study demonstrated that emicizumab modulates macrophages phenotype, binds to FcɣRI receptor and activates Syk signalling pathway. These original data open new perspectives in understanding of the cellular and tissue effects of emicizumab.