[N-methyl-D-aspartate receptor antibody encephalitis: value of immunomodulatory therapy].
BACKGROUND
Anti-N-methyl-D-aspartate receptor (NMDA-R) encephalitis is little known to pediatricians and likely underdiagnosed. The child's vital and cognitive prognosis is at stake. The use of immunomodulatory drugs, such as rituximab has led to spectacular results, but many questions remain about its mode of action in this type of pathology.


METHODS
We report the case of a 6-year-old girl with no medical history, admitted for status epilepticus preceded by behavior symptoms and sleep disorders. Gradually, the child became bedridden, mute, and animated by predominantly orofacial dyskinesia. Examinations were normal (cerebrospinal fluid [CSF] analysis, brain MRI). The diagnosis was established by the presence of NMDA-R antibodies in the CSF. After exclusion of a tumor-associated syndrome, treatment was started initially by intravenous immunoglobulins, then by plasma exchange, and finally rituximab. The patient was cured with rituximab despite an unusually early recovery of the B-cell pool.


CONCLUSIONS
Anti-N-methyl-D-aspartate receptor (NMDA-R) encephalitis is a severe but potentially reversible neurologic disorder only recently described, even in childhood. It may be reversible without sequelae if diagnosed and treated early. The use of immunomodulatory therapy, such as rituximab seemingly improves the outcome. Immunological monitoring is needed to better understand its mechanism of action in autoimmune diseases of the nervous system in childhood.
Service de neuropédiatrie, unité Inserm U930, hôpital d'Enfants Gatien de Clocheville, université de Tours, CHU de Tours, 49, boulevard Béranger, 37044 Tours cedex 01, France.
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Le Moigno
Laboratoire d'immunologie, Labex Mab Improve, CHRU de Tours, 37000 Tours, France.
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Ternant
Laboratoire d'immunologie, Labex Mab Improve, CHRU de Tours, 37000 Tours, France; Université François-Rabelais de Tours, 37044 Tours, France.
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Paintaud
Laboratoire d'immunologie, Labex Mab Improve, CHRU de Tours, 37000 Tours, France.
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Thibault
Unité de néphrologie pédiatrique, hôpital Clocheville, CHRU de Tours, 37000 Tours, France.
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Cloarec
Service de neuropédiatrie, Centre de référence des maladies inflammatoires du cerveau, AP-HP, 94275 Le Kremlin-Bicêtre, France.
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M
Tardieu
Service de neuropédiatrie, unité Inserm U930, hôpital d'Enfants Gatien de Clocheville, université de Tours, CHU de Tours, 49, boulevard Béranger, 37044 Tours cedex 01, France.
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E
Lagrue
Service de neuropédiatrie, unité Inserm U930, hôpital d'Enfants Gatien de Clocheville, université de Tours, CHU de Tours, 49, boulevard Béranger, 37044 Tours cedex 01, France; Université François-Rabelais de Tours, 37044 Tours, France; UMR Inserm U930, CNRS FRE 2448, 37044 Tours, France. Electronic address: castelnau@med.univ-tours.fr.
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Castelnau
D060426:Anti-N-Methyl-D-Aspartate Receptor Encephalitis / Q000175:diagnosis* / Q000628:therapy*; D000906:Antibodies / Q000134:cerebrospinal fluid; D058846:Antibodies, Monoclonal, Murine-Derived / Q000627:therapeutic use; D002648:Child; D005260:Female; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000627:therapeutic use; D007155:Immunologic Factors / Q000627:therapeutic use; D010951:Plasma Exchange; D016194:Receptors, N-Methyl-D-Aspartate / Q000276:immunology; D000069283:Rituximab
D000906:Antibodies; D058846:Antibodies, Monoclonal, Murine-Derived; D016756:Immunoglobulins, Intravenous; D007155:Immunologic Factors; D016194:Receptors, N-Methyl-D-Aspartate; D000069283:Rituximab