1. Pathology Department Hospital Morvan Brest France
2. Department of Hematology, Transplantation Division Hôpital Saint‐Louis Paris France
3. Hematology Department Pitie‐Salpetriere Hospital Paris France
4. Centre d'Immunologie et des Maladies Infectieuses (CIMI‐Paris) Sorbonne Université, Inserm U1135, CNRS ERL 8255 Paris France
5. LBAI, UMR1227 Univ Brest, Inserm Brest France
6. Adolescents and Young Adults Unit Hôpital Saint‐Louis, Assistance Publique – Hôpitaux de Paris Paris France
7. Neuropathology department, APHP, Pitié Salpétrière Sorbonne University Paris France
8. Department of Clinical Neurophysiology, AP‐HP Pitié‐Salpêtrière Hospital Paris France
9. Dermatology Department, Hôpital Saint‐Louis Assistance Publique‐Hôpitaux de Paris Paris France
10. Sorbonne Université, Assistance Publique Hôpitaux de Paris, Department of Internal Medicine and Clinical Immunology Pitié‐Salpêtrière Hospital Paris France
11. Neuromyology Department AP‐HP, Pitié‐Salpêtrière Hospital Sorbonne University Paris France
12. Internal medicine Dpt, Hôpital Saint‐Louis, APHP Université Paris‐Cité, INSERM U976‐HIPI, Centre de Référence des Maladies Auto‐Immunes Systémiques Rares d'Ile‐de‐France, Filière FAI2R Paris France