1. Relevance of anti-HNK1 antibodies in the management of anti-MAG neuropathies
- Author
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Alexandre Brodovich, José Boucraut, Stéphane Paul, Emilien Delmont, Jean-Christophe Antoine, Aude-Marie Grapperon, Shahram Attarian, Jean Philippe Camdessanché, Institut de Neurosciences des Systèmes (INS), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM), and Institut National de la Santé et de la Recherche Médicale (INSERM)
- Subjects
Male ,Epitope ,03 medical and health sciences ,Myelin ,CD57 Antigens ,0302 clinical medicine ,Humans ,Medicine ,030212 general & internal medicine ,ComputingMilieux_MISCELLANEOUS ,Aged ,Autoantibodies ,Aged, 80 and over ,Myelin-associated glycoprotein ,biology ,business.industry ,[SCCO.NEUR]Cognitive science/Neuroscience ,Disease Management ,Peripheral Nervous System Diseases ,Middle Aged ,medicine.disease ,IgM Monoclonal Gammopathy ,Myelin-Associated Glycoprotein ,Peripheral neuropathy ,medicine.anatomical_structure ,nervous system ,Neurology ,Immunology ,biology.protein ,Biomarker (medicine) ,Female ,Rituximab ,Neurology (clinical) ,Antibody ,business ,Biomarkers ,030217 neurology & neurosurgery ,medicine.drug - Abstract
In peripheral neuropathies with antibodies against Myelin Associated Glycoprotein (MAG), an IgM monoclonal gammopathy recognizes a specific epitope called Human Natural Killer 1 (HNK1) shared by NK lymphocytes and several components of the peripheral nerve myelin. Recently an ELISA test has been developed to detect antibodies against HNK1 epitope. Objectives were to determine the usefulness of this assay in the management of anti-MAG neuropathy. Anti-HNK1 antibodies were assessed with the GanglioCombi™ MAG ELISA test (Buhlmann) in 41 anti-MAG neuropathies and in 118 controls: 34 chronic inflammatory demyelinating polyradiculoneuropathies, 3 Miller Fisher syndromes, 12 sensory neuronopathies, 63 length-dependent axonal sensory polyneuropathies, 6 healthy controls. Anti-HNK1 antibody was tested before and 1 year after rituximab therapy in seven patients with anti-MAG neuropathy. Anti-HNK1 antibodies were positive in 40/41 anti-MAG neuropathies, and in 1/118 controls (sensitivity 98%, specificity 99%). Only considering controls with IgM paraprotein, specificity was 96% (23/24). In anti-MAG neuropathies, anti-HNK1 titre was correlated with sensory deficiency evaluated with the INCAT sensory sum score (r = 0.4, p = 0.01) and with disability evaluated with the Rasch-built Overall Disability Scale (r = $$-$$ 0.4, p = 0.01) and Overall Neuropathy Limitation Scale (r = 0.4, p = 0.02). Anti-HNK1 titres were not related to age, disease duration, atypical clinical features and anti-MAG antibodies titres. Anti-MAG titres were not associated with disease severity. Anti-HNK1 titres were decreased by 18% 1 year after rituximab treatment. Anti-HNK1 antibodies have good sensitivity and specificity for the diagnosis of anti-MAG neuropathy. Interestingly, anti-HNK1 titres are related to the disease severity and decrease after rituximab infusions.
- Published
- 2019
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