Autoimmune Encephalitis and Other Neurological Syndromes With Rare Neuronal Surface Antibody in Children after hematopoietic stem cell transplantation

Abstract

Abstract Introduction: Neuronal surface antibody syndromes (NSAS) are an expanding group of autoimmune neurological diseases, whose most frequent clinical manifestation is autoimmune encephalitis (AE). Anti-N-methyl-D-aspartate receptor (NMDAR) autoimmunity represent the most described form, while other NSAS such as anti-metabotropic glutamate receptor-5 (mGluR5) are rarer and less well-characterized, especially in children. Case description: Here, we carried out a case of a 7-year-old girl with abnormal behavior after hematopoietic stem cell transplantation (HSCT). She was diagnosed as anti-mGluR5 AE and the Electroencephalogram (EEG) showed increased number of generalized slow waves in the waking-period. Intravenous injection of gamma globulin and methylprednisolone followed by oral administration of prednisone tablets. During hormone shock therapy, levetiracetam was given anti epileptic treatment. The abnormal behaviors improved significantly after treatment. Discussion and Evaluation: The mechanism of anti-mGluR5 AE after HSCT is unclear. Impairment of glutamatergic synaptic transmission by anti-neuronal surface GluR antibodies is increasingly recognized as a major cause of AE in humans. Conclusions: To our knowledge, this is the first report on rare pediatric NSAS of anti-mGluR5 AE after HSCT. An improved characterization may aid our recognition and treatment in children. Serum antibody testing in HSCT patients with negative cerebrospinal fluid autoimmune antibodies may allow the early identification and treatment of anti-mGluR5 AE.