Ludivine Kouton1, José Boucraut2, Jérome Devaux3, Yusuf A Rajabally4, David Adams5, Jean Christophe Antoine6, Frédéric Bourdain7, Alexandre Brodovitch8, Jean-Philippe Camdessanché6, Cécile Cauquil5, Jonathan Ciron9, Thierry Dubard10, Andoni Echaniz-Laguna11, Aude-Marie Grapperon1, Raul Juntas-Morales12, Laurent Kremer13, Thierry Kuntzer14, Céline Labeyrie5, Luca Lanfranco15, Jean-Marc Léger16, Thierry Maisonobe16, Nicolas Mavroudakis17, Sylvie Mecharles-Darrigol18, Philippe Merle19, Jean-Baptiste Noury20, Violaine Rouaud21, Céline Tard22, Marie Théaudin14, Jean-Michel Vallat23, Karine Viala16, Shahram Attarian1, Emilien Delmont24. 1. Referral Centre for Neuromuscular Diseases and ALS, La Timone hospital, Marseille, France. 2. Immunology Laboratory, La Conception Hospital, Marseille, France; Aix-Marseille University, Timone Neuroscience Institute, UMR CNRS 7289, 13005 Marseille, France. 3. Institut de Neurosciences de Montpellier, Montpellier, France. 4. Department of Neurology, Aston Medical School, Aston University, Birmingham, UK. 5. Referral Centre for Peripheral Neuropathies, CHU Bicetre, APHP, Paris, France. 6. Department of Neurology, Saint Etienne, France. 7. Department of Neurology, Hôpital Foch, Paris, France. 8. Referral Centre for Neuromuscular Diseases and ALS, La Timone hospital, Marseille, France; Immunology Laboratory, La Conception Hospital, Marseille, France. 9. Department of Neurology, Toulouse, France. 10. Department of Neurology, Reims, France. 11. Referral Centre for Peripheral Neuropathies, CHU Bicetre, APHP, Paris, France; INSERM U1195, Paris-Sud University, Le Kremlin Bicêtre, France. 12. Department of Neurology, Montpellier, France. 13. Department of Neurology, INSERM U1119, Biopathologie de la Myéline, Neuroprotection et Stratégies Thérapeutiques, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg, France. 14. Nerve Muscle Unit, Department of Clinical Neurosciences, Lausanne University Hospital, Lausanne, Switzerland. 15. Department of Nephrology, Brest, France. 16. Department of Neurology, APHP, Hôpital Pitie Salpêtrière, France. 17. Department of Neurology, Hôpital Erasme, Bruxelles, Belgium. 18. Department of Neurology, Pointe A Pitre, France. 19. Department of Clinical Neurophysiology, Amiens, France. 20. Department of Neurology, Brest, France. 21. Department of Neurology, Vannes, France. 22. U1171, CHU de Lille, Centre de référence des maladies neuromusculaires Nord Est Ile de France, Department of Neurology, Lille, France. 23. Department of Neurology, Limoges, France. 24. Referral Centre for Neuromuscular Diseases and ALS, La Timone hospital, Marseille, France; Aix-Marseille University, Timone Neuroscience Institute, UMR CNRS 7289, 13005 Marseille, France. Electronic address: emilien.delmont@ap-hm.fr.
Abstract
OBJECTIVE: Chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) with antibodies against neurofascin 155 (Nfasc155) or contactin-1 (CNTN1) have distinctive clinical features. Knowledge on their electrophysiological characteristics is still scarce. In this study, we are investigating whether these patients have specific electrophysiological characteristics. METHODS: The electrophysiological data from 13 patients with anti-Nfasc155 IgG4 antibodies, 9 with anti-CNTN1 IgG4 antibodies were compared with those of 40 consecutive CIDP patients without antibodies. RESULTS: All the patients with antibodies against Nfasc155 or CNTN1 fulfilled the EFNS/PNS electrodiagnostic criteria for definite CIDP. There was no electrophysiological difference between patients with anti-CNTN1 and anti-Nfasc155 antibodies. Nerve conduction abnormalities were heterogeneously distributed along nerves trunks and roots. They were more pronounced than in CIDP without antibodies. Motor conduction velocity on median nerve <24 m/s or motor velocity on ulnar nerve <26 m/s or motor distal latency on ulnar nerve >7.4 ms were predictive of positive antibodies against the node of Ranvier with a sensitivity of 59% and a specificity of 93%. CONCLUSIONS: Marked conduction abnormalities may suggest the presence of positive antibodies against the node of Ranvier. SIGNIFICANCE: Anti-Nfasc155 and anti-CNTN1 antibodies target the the paranodal axo-glial domain but are associated with nerve conduction abnormalities mimicking a "demyelinating" neuropathy.
OBJECTIVE: Chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) with antibodies against neurofascin 155 (Nfasc155) or contactin-1 (CNTN1) have distinctive clinical features. Knowledge on their electrophysiological characteristics is still scarce. In this study, we are investigating whether these patients have specific electrophysiological characteristics. METHODS: The electrophysiological data from 13 patients with anti-Nfasc155 IgG4 antibodies, 9 with anti-CNTN1 IgG4 antibodies were compared with those of 40 consecutive CIDP patients without antibodies. RESULTS: All the patients with antibodies against Nfasc155 or CNTN1 fulfilled the EFNS/PNS electrodiagnostic criteria for definite CIDP. There was no electrophysiological difference between patients with anti-CNTN1 and anti-Nfasc155 antibodies. Nerve conduction abnormalities were heterogeneously distributed along nerves trunks and roots. They were more pronounced than in CIDP without antibodies. Motor conduction velocity on median nerve <24 m/s or motor velocity on ulnar nerve <26 m/s or motor distal latency on ulnar nerve >7.4 ms were predictive of positive antibodies against the node of Ranvier with a sensitivity of 59% and a specificity of 93%. CONCLUSIONS: Marked conduction abnormalities may suggest the presence of positive antibodies against the node of Ranvier. SIGNIFICANCE: Anti-Nfasc155 and anti-CNTN1 antibodies target the the paranodal axo-glial domain but are associated with nerve conduction abnormalities mimicking a "demyelinating" neuropathy.