Summary Background Anti-N-methyl-d-aspartate (NMDA) receptor encephalitis is a severe but treatable autoimmune disorder which diagnosis depends on sensitive and specific antibody testing. We aimed to ...assess the sensitivity and specificity of serum and CSF antibody testing in patients with anti-NMDA receptor encephalitis, and the relation between titres, relapses, outcome, and epitope repertoire. Methods In this observational study, we used rat brain immunohistochemistry and cell-based assays (CBA) with fixed or live NMDA receptor-expressing cells to determine the sensitivity and specificity of antibody testing in paired serum and CSF samples. Samples were obtained at diagnosis from patients with anti-NMDA receptor encephalitis and from control participants worldwide. We deemed a patient to be antibody positive if their serum, their CSF, or both tested positive with both immunohistochemistry and CBA techniques; we determined titres with serial sample dilution using brain immunohistochemistry. We examined samples from 45 patients (25 with good outcome modified Rankin Scale, mRS 0–2, ten with poor outcome mRS 3–6, and ten with relapses) at three or more timepoints. We determined the epitope repertoire in the samples of 23 patients with CBA expressing GluN1-NMDA receptor mutants. Findings We analysed samples from 250 patients with anti-NMDA receptor encephalitis and 100 control participants. All 250 patients had NMDA receptor antibodies in CSF but only 214 had antibodies in serum (sensitivity 100·0% 98·5–100·0% vs 85·6% 80·7–89·4%, p<0·0001). Serum immunohistochemistry testing was more often in agreement with CBA with fixed cells (77 71% of 108) than with CBA with live cells (63 58% of 108, p=0·0056). In multivariable analysis, CSF and serum titres were higher in patients with poor outcome than in those with good outcome (CSF dilution 340 vs 129, difference 211, 95% CI 1–421, p=0·049; serum dilution 7370 vs 1243, difference 6127 2369–9885, p=0·0025), and in patients with teratoma than in those without teratoma (CSF 395 vs 110, difference 285 134–437, p=0·0079; serum 5515 vs 1644, difference 3870 548–7193, p=0·024). Over time there was a decrease of antibody titres in the 35 patients with good or poor outcome and samples followed at three timepoints regardless of outcome (from diagnosis to last follow-up: CSF 614 to 76, difference 538 288–788; serum 5460 to 1564, difference 3896 2428–5362; both p<0·0001). Relapses were associated with a change in titre more often in CSF than in serum (14 of 19 vs seven of 16, p=0·037). After recovery, 24 of 28 CSF samples and 17 of 23 serum samples from patients remained antibody positive. Patients' antibodies targeted a main epitope region at GluN1 aminoacid 369; the epitope repertoire did not differ between patients with different outcomes, and did not change during relapses. Interpretation The sensitivity of NMDA receptor antibody testing is higher in CSF than in serum. Antibody titres in CSF and serum were higher in patients with poor outcome or teratoma than in patients with good outcome or no tumour. The titre change in CSF was more closely related with relapses than was that in serum. These findings emphasise the importance of including CSF in antibody studies, and that antibody titres can complement clinical assessments. Funding Dutch Cancer Society, National Institutes of Health, McKnight Neuroscience of Brain Disorders award, the Fondo de Investigaciones Sanitarias, ErasmusMC fellowship, and Fundació la Marató de TV3.
Summary Encephalitis is a severe inflammatory disorder of the brain with many possible causes and a complex differential diagnosis. Advances in autoimmune encephalitis research in the past 10 years ...have led to the identification of new syndromes and biomarkers that have transformed the diagnostic approach to these disorders. However, existing criteria for autoimmune encephalitis are too reliant on antibody testing and response to immunotherapy, which might delay the diagnosis. We reviewed the literature and gathered the experience of a team of experts with the aims of developing a practical, syndrome-based diagnostic approach to autoimmune encephalitis and providing guidelines to navigate through the differential diagnosis. Because autoantibody test results and response to therapy are not available at disease onset, we based the initial diagnostic approach on neurological assessment and conventional tests that are accessible to most clinicians. Through logical differential diagnosis, levels of evidence for autoimmune encephalitis (possible, probable, or definite) are achieved, which can lead to prompt immunotherapy.
Summary Background Voltage-gated potassium channels are thought to be the target of antibodies associated with limbic encephalitis. However, antibody testing using cells expressing voltage-gated ...potassium channels is negative; hence, we aimed to identify the real autoantigen associated with limbic encephalitis. Methods We analysed sera and CSF of 57 patients with limbic encephalitis and antibodies attributed to voltage-gated potassium channels and 148 control individuals who had other disorders with or without antibodies against voltage-gated potassium channels. Immunohistochemistry, immunoprecipitation, and mass spectrometry were used to characterise the antigen. An assay with HEK293 cells transfected with leucine-rich, glioma-inactivated 1 (LGI1) and disintegrin and metalloproteinase domain-containing protein 22 (ADAM22) or ADAM23 was used as a serological test. The identity of the autoantigen was confirmed by immunoabsorption studies and immunostaining of Lgi1 -null mice. Findings Immunoprecipitation and mass spectrometry analyses showed that antibodies from patients with limbic encephalitis previously attributed to voltage-gated potassium channels recognise LGI1, a neuronal secreted protein that interacts with presynaptic ADAM23 and postsynaptic ADAM22. Immunostaining of HEK293 cells transfected with LGI1 showed that sera or CSF from patients, but not those from control individuals, recognised LGI1. Co-transfection of LGI1 with its receptors, ADAM22 or ADAM23, changed the pattern of reactivity and improved detection. LGI1 was confirmed as the autoantigen by specific abrogation of reactivity of sera and CSF from patients after immunoabsorption with LGI1-expressing cells and by comparative immunostaining of wild-type and Lgi1 -null mice, which showed selective lack of reactivity in brains of Lgi1 -null mice. One patient with limbic encephalitis and antibodies against LGI1 also had antibodies against CASPR2, an autoantigen we identified in some patients with encephalitis and seizures, Morvan's syndrome, and neuromyotonia. Interpretation LGI1 is the autoantigen associated with limbic encephalitis previously attributed to voltage-gated potassium channels. The term limbic encephalitis associated with antibodies against voltage-gated potassium channels should be changed to limbic encephalitis associated with LGI1 antibodies, and this disorder should be classed as an autoimmune synaptic encephalopathy. Funding National Institutes of Health, National Cancer Institute, and Euroimmun.
Summary Background Anti-NMDA receptor (NMDAR) encephalitis is an autoimmune disorder in which the use of immunotherapy and the long-term outcome have not been defined. We aimed to assess the ...presentation of the disease, the spectrum of symptoms, immunotherapies used, timing of improvement, and long-term outcome. Methods In this multi-institutional observational study, we tested for the presence of NMDAR antibodies in serum or CSF samples of patients with encephalitis between Jan 1, 2007, and Jan 1, 2012. All patients who tested positive for NMDAR antibodies were included in the study; patients were assessed at symptom onset and at months 4, 8, 12, 18, and 24, by use of the modified Rankin scale (mRS). Treatment included first-line immunotherapy (steroids, intravenous immunoglobulin, plasmapheresis), second-line immunotherapy (rituximab, cyclophosphamide), and tumour removal. Predictors of outcome were determined at the Universities of Pennsylvania (PA, USA) and Barcelona (Spain) by use of a generalised linear mixed model with binary distribution. Results We enrolled 577 patients (median age 21 years, range 8 months to 85 years), 211 of whom were children (<18 years). Treatment effects and outcome were assessable in 501 (median follow-up 24 months, range 4–186): 472 (94%) underwent first-line immunotherapy or tumour removal, resulting in improvement within 4 weeks in 251 (53%). Of 221 patients who did not improve with first-line treatment, 125 (57%) received second-line immunotherapy that resulted in a better outcome (mRS 0–2) than those who did not (odds ratio OR 2·69, CI 1·24–5·80; p=0·012). During the first 24 months, 394 of 501 patients achieved a good outcome (mRS 0–2; median 6 months, IQR 2–12) and 30 died. At 24 months’ follow-up, 203 (81%) of 252 patients had good outcome. Outcomes continued to improve for up to 18 months after symptom onset. Predictors of good outcome were early treatment (0·62, 0·50–0·76; p<0·0001) and no admission to an intensive care unit (0·12, 0·06–0·22; p<0·0001). 45 patients had one or multiple relapses (representing a 12% risk within 2 years); 46 (67%) of 69 relapses were less severe than initial episodes (p<0·0001). In 177 children, predictors of good outcome and the magnitude of effect of second-line immunotherapy were similar to those of the entire cohort. Interpretation Most patients with anti-NMDAR encephalitis respond to immunotherapy. Second-line immunotherapy is usually effective when first-line treatments fail. In this cohort, the recovery of some patients took up to 18 months. Funding The Dutch Cancer Society, the National Institutes of Health, the McKnight Neuroscience of Brain Disorders award, The Fondo de Investigaciones Sanitarias, and Fundació la Marató de TV3.
Summary Background Increasing evidence suggests that seizures and status epilepticus can be immune-mediated. We aimed to describe the clinical features of a new epileptic disorder, and to establish ...the target antigen and the effects of patients' antibodies on neuronal cultures. Methods In this observational study, we selected serum and CSF samples for antigen characterisation from 140 patients with encephalitis, seizures or status epilepticus, and antibodies to unknown neuropil antigens. The samples were obtained from worldwide referrals of patients with disorders suspected to be autoimmune between April 28, 2006, and April 25, 2013. We used samples from 75 healthy individuals and 416 patients with a range of neurological diseases as controls. We assessed the samples using immunoprecipitation, mass spectrometry, cell-based assay, and analysis of antibody effects in cultured rat hippocampal neurons with confocal microscopy. Findings Neuronal cell-membrane immunoprecipitation with serum of two index patients revealed GABAA receptor sequences. Cell-based assay with HEK293 expressing α1/β3 subunits of the GABAA receptor showed high titre serum antibodies (>1:160) and CSF antibodies in six patients. All six patients (age 3–63 years, median 22 years; five male patients) developed refractory status epilepticus or epilepsia partialis continua along with extensive cortical-subcortical MRI abnormalities; four patients needed pharmacologically induced coma. 12 of 416 control patients with other diseases, but none of the healthy controls, had low-titre GABAA receptor antibodies detectable in only serum samples, five of them also had GAD-65 antibodies. These 12 patients (age 2–74 years, median 26·5 years; seven male patients) developed a broader spectrum of symptoms probably indicative of coexisting autoimmune disorders: six had encephalitis with seizures (one with status epilepticus needing pharmacologically induced coma; one with epilepsia partialis continua), four had stiff-person syndrome (one with seizures and limbic involvement), and two had opsoclonus-myoclonus. Overall, 12 of 15 patients for whom treatment and outcome were assessable had full (three patients) or partial (nine patients) response to immunotherapy or symptomatic treatment, and three died. Patients' antibodies caused a selective reduction of GABAA receptor clusters at synapses, but not along dendrites, without altering NMDA receptors and gephyrin (a protein that anchors the GABAA receptor). Interpretation High titres of serum and CSF GABAA receptor antibodies are associated with a severe form of encephalitis with seizures, refractory status epilepticus, or both. The antibodies cause a selective reduction of synaptic GABAA receptors. The disorder often occurs with GABAergic and other coexisting autoimmune disorders and is potentially treatable. Funding The National Institutes of Health, the McKnight Neuroscience of Brain Disorders, the Fondo de Investigaciones Sanitarias, Fundació la Marató de TV3, the Netherlands Organisation for Scientific Research (Veni-incentive), the Dutch Epilepsy Foundation.
Sabater and colleagues reported1 eight patients with a novel parasomnia with sleep breathing dysfunction associated with IgG4 antibodies to IgLON5, a neuronal surface cell adhesion molecule, and ...extensive deposits of hyperphosphorylated tau in the tegmentum and hypothalamus, raising questions about the possible autoimmune or neurodegenerative mechanisms of the disorder. The association with HLA DRB1*1001 and DQB1*0501 alleles, an HLA with a very low prevalence in the population,2 and the presence of IgLON5 antibodies implied an autoimmune cause, whereas the chronic clinical course, poor response to immunotherapy, and pathological findings suggested a neurodegenerative process.
Summary Background Autoimmunity might be associated with or implicated in sleep and neurodegenerative disorders. We aimed to describe the features of a novel neurological syndrome associated with ...prominent sleep dysfunction and antibodies to a neuronal antigen. Methods In this observational study, we used clinical and video polysomnography to identify a novel sleep disorder in three patients referred to the Sleep Unit of Hospital Clinic, University of Barcelona, Spain, for abnormal sleep behaviours and obstructive sleep apnoea. These patients had antibodies against a neuronal surface antigen, which were also present in five additional patients referred to our laboratory for antibody studies. These five patients had been assessed with polysomnography, which was done in our sleep unit in one patient and the recording reviewed in a second patient. Two patients underwent post-mortem brain examination. Immunoprecipitation and mass spectrometry were used to characterise the antigen and develop an assay for antibody testing. Serum or CSF from 298 patients with neurodegenerative, sleep, or autoimmune disorders served as control samples. Findings All eight patients (five women; median age at disease onset 59 years range 52–76) had abnormal sleep movements and behaviours and obstructive sleep apnoea, as confirmed by polysomnography. Six patients had chronic progression with a median duration from symptom onset to death or last visit of 5 years (range 2–12); in four the sleep disorder was the initial and most prominent feature, and in two it was preceded by gait instability followed by dysarthria, dysphagia, ataxia, or chorea. Two patients had a rapid progression with disequilibrium, dysarthria, dysphagia, and central hypoventilation, and died 2 months and 6 months, respectively, after symptom onset. In five of five patients, video polysomnography showed features of obstructive sleep apnoea, stridor, and abnormal sleep architecture (undifferentiated non-rapid-eye-movement non-REM sleep or poorly structured stage N2, simple movements and finalistic behaviours, normalisation of non-REM sleep by the end of the night, and, in the four patients with REM sleep recorded, REM sleep behaviour disorder). Four of four patients had HLA-DRB1*1001 and HLA-DQB1*0501 alleles. All patients had antibodies (mainly IgG4) against IgLON5, a neuronal cell adhesion molecule. Only one of the 298 controls, who had progressive supranuclear palsy, had IgLON5 antibodies. Neuropathology showed neuronal loss and extensive deposits of hyperphosphorylated tau mainly involving the tegmentum of the brainstem and hypothalamus in the two patients studied. Interpretation IgLON5 antibodies identify a unique non-REM and REM parasomnia with sleep breathing dysfunction and pathological features suggesting a tauopathy. Funding Fondo de Investigaciones Sanitarias, Centros de Investigación Biomédica en Red de enfermedades neurodegenerativas (CIBERNED) and Respiratorias (CIBERES), Ministerio de Economía y Competitividad, Fundació la Marató TV3, and the National Institutes of Health.
Summary The management of primary CNS lymphoma is one of the most controversial topics in neuro-oncology because of the complexity of the disease and the very few controlled studies available. In ...2013, the European Association of Neuro-Oncology created a multidisciplinary task force to establish evidence-based guidelines for immunocompetent adults with primary CNS lymphoma. In this Review, we present these guidelines, which provide consensus considerations and recommendations for diagnosis, assessment, staging, and treatment of primary CNS lymphoma. Specifically, we address aspects of care related to surgery, systemic and intrathecal chemotherapy, intensive chemotherapy with autologous stem-cell transplantation, radiotherapy, intraocular manifestations, and management of elderly patients. The guidelines should aid clinicians in their daily practice and decision making, and serve as a basis for future investigations in neuro-oncology.
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