Clinical characteristics, treatments, and outcomes of patients with anti-N-methyl-d-aspartate receptor encephalitis: A systematic review of reported cases.

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is a recently recognized autoimmune disorder which is responsive to immunotherapy. However, the outcomes of different immunotherapies have not been defined and there have been few studies that carried out a comparison among them. To provide an overview of the clinical characteristics, treatments, and outcomes of anti-NMDAR encephalitis, we systematically reviewed the literature in the PubMed, Medline, Embase, Cochrane Library, BioMedical Literature Database (CBM), China National Knowledge Infrastructure (CNKI), and Wan-fang databases. Eighty-three studies with a total of 432 patients were included. The median age was 22years. Two hundred ninety-three (68%) patients were female, 87 (21%) of 412 patients had a tumor, including 68 (78%) patients with ovarian teratoma. Pediatric patients had a higher ratio of seizures to psychiatric symptoms as the initial manifestation (p=0.0012), a lower proportion with a tumor (p<0.0001) and CSF pleocytosis (p=0.0163), and a better outcome (p=0.0064) than adults. Patients who died had a higher proportion of CSF pleocytosis than the patients who survived (p=0.0021). There were no significant differences among three first-line immunotherapy used alone (p=0.9172) or among combinations of every two of them (p=0.3059). With regard to the use of corticosteroid and IVIG, there were no significant differences between the outcomes of early combined treatment and sequential treatment (p=0.7277), or between using corticosteroid first and IVIG first (p=0.5422). Our findings suggest that the clinical characteristics and outcomes for pediatric patients were different from adult patients, and no significant differences were found among different immunotherapies.

Co-expression of NMDA-receptor subunits NR1, NR2A, and NR2B in dysplastic neurons of teratomas in patients with paraneoplastic NMDA-receptor-encephalitis: a retrospective clinico-pathology study of 159 patients.

OBJECTIVE: To comprehensively describe the pathological features of neurons in patients with ovarian teratomas and paraneoplastic anti-NMDAR encephalitis (anti-NMDARE), emphasizing on NMDA-receptor expression and infiltrating lymphocytes. METHODS: A retrospective study was performed in a large series of 159 patients from the West China Hospital. We retrospectively identified 12 patients with paraneoplastic anti-NMDARE (11 case with ovarian teratomas and 1 case with mixed germ cell tumor), which were compared to 35 patients with teratomas and no encephalitis and to 147 patients with anti-NMDARE and no evidence for tumors. Patient history and outcome were reviewed from the clinical charts and compared between all three groups. Histopathological examination, including double-immunofluorescence of NMDAR subunits and IgG was performed in all teratoma tissues. Magnetic Luminex Assay Human Premixed Multi-Analyte Kit was performed to investigate cytokines profile of CSF. RESULTS: Patients with paraneoplastic anti-NMDARE had a more severe clinical presentation, i.e. they required more mechanical ventilation and intensive care (p < 0.001). Though immunotherapy was initiated earlier in this group, repeated intravenous immunoglobulin administration (IVIG) was more common (p = 0.002) and with higher cerebrospinal fluid (CSF) antibody titres (p = 0.004). Following tumor resection, the outcome did not differ between groups. A peculiar population of floating-frog like dysplastic neurons were observed only in teratomas of patients with paraneoplastic anti-NMDARE, co-expressing NR1, NR2A, NR2B subunits and IgG. Also, CD20 positive B-cells were more common in anti-NMDARE teratomas. In CSF of paraneoplastic anti-NMDARE patients, TNF-α, IL-10 and GM-CSF concentrations were higher than in negative symptom control and VEGF-A and IL-1a were lower than in anti-NMDARE patients (0.25 < p < 0.05). CONCLUSIONS: Patients with teratomas and paraneoplastic anti-NMDARE revealed a cellular population of dysplastic neurons co-expressing NMDAR subunits, which were the potential source of autoantigens triggering anti-NMDARE. Some inflammatory cytokines may be involved in pathogenesis of paraneoplastic anti-NMDARE.