N-methyl-D-aspartate antibody encephalitis: temporal progression of clinical and paraclinical observations in a predominantly non-paraneoplastic disorder of both sexes.

Department of Clinical Neurology, L6 West Wing, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK.
Brain (Impact Factor: 10.23). 06/2010; 133(Pt 6):1655-67. DOI: 10.1093/brain/awq113
Source: PubMed

ABSTRACT Antibodies to the N-methyl-d-aspartate subtype of glutamate receptor have been associated with a newly-described encephalopathy that has been mainly identified in young females with ovarian tumours. However, the full clinical spectrum and treatment responses are not yet clear. We established a sensitive cell-based assay for detection of N-methyl-d-aspartate receptor antibodies in serum or cerebrospinal fluid, and a quantitative fluorescent immunoprecipitation assay for serial studies. Although there was marked intrathecal synthesis of N-methyl-d-aspartate receptor antibodies, the absolute levels of N-methyl-d-aspartate receptor antibodies were higher in serum than in cerebrospinal fluid. N-methyl-d-aspartate receptor antibodies were of the immunoglobulin G1 subclass and were able to activate complement on N-methyl d-aspartate receptor-expressing human embryonic kidney cells. From questionnaires returned on 44 N-methyl-d-aspartate receptor antibody-positive patients, we identified a high proportion without a detected tumour (35/44, 80%: follow-up 3.6-121 months, median 16 months). Among the latter were 15 adult females (43%), 10 adult males (29%) and 10 children (29%), with four in the first decade of life. Overall, there was a high proportion (29%) of non-Caucasians. Good clinical outcomes, as defined by reductions in modified Rankin scores, correlated with decreased N-methyl-d-aspartate receptor antibody levels and were associated with early (<40 days) administration of immunotherapies in non-paraneoplastic patients (P < 0.0001) and earlier tumour removal in paraneoplastic patients (P = 0.02). Ten patients (23%) who were first diagnosed during relapses had no evidence of tumours but had received minimal or no immunotherapy during earlier episodes. Temporal analysis of the onset of the neurological features suggested progression through two main stages. The time of onset of the early features, characterized by neuropsychiatric symptoms and seizures preceded by a median of 10-20 days, the onset of movement disorders, reduction in consciousness and dysautonomia. This temporal dichotomy was also seen in the timing of cerebrospinal fluid, electroencephalographic and in the rather infrequent cerebral imaging changes. Overall, our data support a model in which the early features are associated with cerebrospinal fluid lymphocytosis, and the later features with appearance of oligoclonal bands. The immunological events and neuronal mechanisms underlying these observations need to be explored further, but one possibility is that the early stage represents diffusion of serum antibodies into the cortical grey matter, whereas the later stage results from secondary expansion of the immunological repertoire within the intrathecal compartment acting on subcortical neurons. Four patients, who only had temporal lobe epilepsy without oligoclonal bands, may represent restriction to the first stage.

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Available from: Patrick Joseph Waters, Jun 30, 2015
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    ABSTRACT: In 2007, serum IgG autoantibodies to the NMDAR (NMDAR-Ab) were identified in subjects with an autoimmune encephalopathy responsive to immunotherapy; two thirds of whom present with psychiatric symptoms (Dalmau et al., 2007, Irani et al., 2010 and Titulaer et al., 2013). There is increasing evidence for NMDAR-hypofunction and neuroinflammation in the pathophysiology of first episode schizophrenia (Kahn and Sommer, 2014). Whilst many patients with NMDAR-ab develop a widespread encephalopathy, restricted phenotypes, including isolated psychosis, epilepsy, or movement disorders have also been described (Irani et al., 2010, Zandi et al., 2011, Brenner et al., 2013, Titulaer et al., 2013 and Hacohen et al., 2014). We reported in 2010 for the first time IgG NMDAR, and voltage gated potassium channel-complex (VGKC), antibodies in 3 of 46 (6.5%) patients with a first episode psychosis without other neurological symptoms (Zandi et al., 2011). Pollak and colleagues, found IgG NMDAR-ab in 1.46% (95% CI 0.94–2.23) cases of psychosis and schizophrenia from 7 studies, compared to (5/1598) 0.3% controls, but a variety of assays including fixed assays were compared (Pollak et al., 2013). In their analysis, rates of IgA and IgM antibodies were higher in both cases (7.1%) and controls (10.2%), though IgA and IgM antibodies are of unlikely pathogenic relevance. Dalmau and colleagues found isolated psychotic episodes in 23/571 (4%) patients with NMDAR-Ab encephalitis either in presentation (5) or at relapse (18) (Kayser et al., 2013). One test of clinical relevance of autoantibodies is the immunotherapy response. Here we describe 18 cases of acute psychosis with NMDAR-ab measured by live cell based assay without clear clinical ‘neurological’ involvement, 9 of whom we treated with immunotherapy.
    Schizophrenia Research 11/2014; DOI:10.1016/j.schres.2014.11.001 · 4.43 Impact Factor
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    ABSTRACT: Importance Anti-N-methyl-d-aspartate receptor (anti-NMDAR) autoimmune encephalitis is an increasingly recognized cause of limbic encephalitis (LE). Prolonged LE and limbic status epilepticus (LSE) share many features. The ability to distinguish between the two is crucial in directing appropriate therapy because of the potential iatrogenesis associated with immunosuppression and anesthetic-induced coma. Observations A 34-year-old woman with recurrent LE developed behavioral changes, global aphasia, and repetitive focal and generalized tonic–clonic seizures. Because asymmetric rhythmic delta patterns recurred on electroencephalography (EEG) despite treatment with nonsedating antiepileptic drugs followed by anesthetic-induced coma, an investigation to distinguish LSE from LE was undertaken. Implanted limbic/temporal lobe depth electrodes revealed no epileptiform activity. Brain single-photon emission computerized tomography (SPECT) showed no hyperperfusion, and brain fluorodeoxyglucose-positron emission tomography (FDG-PET) showed hypermetabolism in the left frontal, temporal, and parietal cortices. Anti-N-methyl-d-aspartate receptor autoimmune encephalitis was diagnosed based detection of anti-NMDAR antibody in the cerebrospinal fluid (CSF). With chronic immunosuppression, the resolution of brain FDG-PET abnormalities paralleled clinical improvement. Conclusions and relevance This case of anti-NMDAR autoimmune encephalitis illustrates the challenges of distinguishing prolonged LE from LSE. We discuss the parallels between these two conditions and propose a management paradigm to optimize evaluation and treatment.
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