Semi-quantitative analyses of antibodies to N-methyl-d-aspartate type glutamate receptor subunits (GluN2B & GluN1) in the clinical course of Rasmussen syndrome

Case report: Evolution of catatonic mutism and psychotic symptoms in an adolescent with Down syndrome: transition from Down syndrome disintegrative disorder to anti-N-methyl-D-aspartate receptor encephalitis

During her first year of junior high school, a 12-year-old Japanese girl with Down syndrome experienced dizziness, gait disruption, paroxysmal weakness in her hands, and sluggish speaking. Regular blood tests and a brain MRI revealed no abnormalities, and she was tentatively diagnosed with adjustment disorder. Nine months later, the patient experienced a subacute sickness of chest pain, nausea, sleep problem with night terrors, and delusion of observation. Rapid deterioration then developed with simultaneous fever, akinetic mutism, loss of facial expression, and urine incontinence. These catatonic symptoms improved after a few weeks after admission and treatment with lorazepam, escitalopram, and aripiprazole. After discharge, nonetheless, daytime slumber, empty eyes, paradoxical laughter, and declined verbal communication persisted. Upon confirmation of the cerebrospinal N-methyl-D-aspartate (NMDA) receptor autoantibody, methylprednisolone pulse therapy was tried, but it had little effect. Visual hallucinations and cenesthopathy, as well as suicidal thoughts and delusions of death, have predominated in the following years. Cerebrospinal IL-1ra, IL-5, IL-15, CCL5, G-CSF, PDGFbb, and VFGF were raised in the early stage of initial medical attention with nonspecific complaints, but were less prominent in the later stages of catatonic mutism and psychotic symptoms. We suggest a disease concept of progression from Down syndrome disintegrative disorder to NMDA receptor encephalitis, based on this experience.

Case Report: Rituximab Improved Epileptic Spasms and EEG Abnormalities in an Infant With West Syndrome and Anti-NMDAR Encephalitis Associated With APECED

Background: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy is a rare autosomal recessive disorder caused by a mutation in the autoimmune regulator gene. Patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy typically exhibit hypoparathyroidism, adrenocortical failure, and chronic mucocutaneous candidiasis. There are only a few case reports of autoimmune encephalitis during autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, but not as an initial manifestation. Furthermore, there are no reports of patients with infantile spasms/West syndrome with autoimmune encephalitis, partly because the median age for paediatric patients with anti-N-methyl-D-aspartate receptor encephalitis, which is the most frequent and best characterised in paediatric autoimmune encephalitides, is 13–14 years. Herein, we present a case of a 3-month-old infant with autoimmune encephalitis as an initial manifestation of autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy who later developed infantile spasms/West syndrome.

Case Presentation: A 3-month-old girl was admitted to our hospital with a fever, involuntary movements in all four limbs, and right-side facial palsy. Acute central nervous system demyelination diseases were suspected from neuroimaging findings and the presence of the cerebrospinal fluid oligoclonal band. She did not respond to multiple methylprednisolone pulse therapies and later developed infantile spasms/West syndrome and diabetes mellitus. Rituximab, a chimeric mouse/human monoclonal antibody directed against human CD20 which depletes B cells, was initially administered as a treatment for autoimmune encephalitis. Unexpectedly, this treatment resulted in complete spasm cessation and resolution of hypsarrhythmia. The patient eventually showed severely delayed developmental milestones, and her electroencephalography findings showed periodic generalised slow spike-and-wave pattern.

Conclusions: Despite the limited ability to extrapolate findings from a single case, rituximab's effects may suggest that B cells play a crucial role in infantile spasms/West syndrome mechanisms; use of rituximab as an aetiology-specific treatment for infantile spasms/West syndrome patients with autoimmune encephalitis or its effectiveness for infantile spasms/West syndrome patients with other underlying mechanisms warrants further investigation.

N-methyl-D-aspartate Receptor Antibody and White Matter Deficits in Schizophrenia Treatment-Resistance

Insufficient or lack of response to antipsychotic medications in some patients with schizophrenia is a major challenge in psychiatry, but the underlying mechanisms remain unclear. Two seemingly unrelated observations, cerebral white matter and N-methyl-D-aspartate receptor (NMDAR) hypofunction, have been linked to treatment-resistant schizophrenia (TRS). As NMDARs are critical to axonal myelination and signal transduction, we hypothesized that NMDAR antibody (Ab), when present in schizophrenia, may impair NMDAR functions and white matter microstructures, contributing to TRS. In this study, 50 patients with TRS, 45 patients with nontreatment-resistant schizophrenia (NTRS), 53 patients with schizophrenia at treatment initiation schizophrenia (TIS), and 90 healthy controls were enrolled. Serum NMDAR Ab levels and white matter diffusion tensor imaging fractional anisotropy (FA) were assessed. The white matter specificity effects by NMDAR Ab were assessed by comparing with effects on cortical and subcortical gray matter. Serum NMDAR Ab levels of the TRS were significantly higher than those of the NTRS (P = .035). In patients with TRS, higher NMDAR Ab levels were significantly associated with reduced whole-brain average FA (r = -.37; P = .026), with the strongest effect at the genu of corpus callosum (r = -.50; P = .0021, significant after correction for multiple comparisons). Conversely, there was no significant correlation between whole-brain or regional cortical thickness or any subcortical gray matter structural volume and NMDAR Ab levels in TRS. Our finding highlights a potential NMDAR mechanism on white matter microstructure impairment in schizophrenia that may contribute to their treatment resistance to antipsychotic medications.

NMDA and AMPA Receptor Autoantibodies in Brain Disorders: From Molecular Mechanisms to Clinical Features

The role of autoimmunity in central nervous system (CNS) disorders is rapidly expanding. In the last twenty years, different types of autoantibodies targeting subunits of ionotropic glutamate receptors have been found in a variety of patients affected by brain disorders. Several of these antibodies are directed against NMDA receptors (NMDAR), mostly in autoimmune encephalitis, whereas a growing field of research has identified antibodies against AMPA receptor (AMPAR) subunits in patients with different types of epilepsy or frontotemporal dementia. Several in vitro and in vivo studies performed in the last decade have dramatically improved our understanding of the molecular and functional effects induced by both NMDAR and AMPAR autoantibodies at the excitatory glutamatergic synapse and, consequently, their possible role in the onset of clinical symptoms. In particular, the method by which autoantibodies can modulate the localization at synapses of specific target subunits leading to functional impairments and behavioral alterations has been well addressed in animal studies. Overall, these preclinical studies have opened new avenues for the development of novel pharmacological treatments specifically targeting the synaptic activation of ionotropic glutamate receptors.

Exploratory investigation on antibodies to GluN1 and cognitive dysfunction in patients with chronic autoimmune psychosis

INTRODUCTION

Mild cognitive dysfunction has been implicated in a number of psychiatric diseases and affects social functioning. Although clinical criteria were recently proposed for autoimmune psychosis (AP), biomarkers have not yet been established for the severity and prognosis of cognitive dysfunction. We herein investigated the relationships between 3 types of serum antibodies and cognitive dysfunction in chronic psychiatric patients suspected of AP.

METHODS

We included 31 patients suspected of AP and obtained information on their clinical characteristics. Three types of autoantibodies (the anti-N-methyl-_D-aspartate receptor (anti-NMDAR Ab), anti-N-terminal of GluN1 (anti-GluN1-NT Ab), and anti-thyroid antibodies) were evaluated in serum. Cognitive function was assessed using Wechsler Adult Intelligence Scale-III. We examined the relationships between serum autoantibodies and cognitive dysfunction in patients using multiple regression models.

RESULTS

Serum titers of anti-GluN1-NT Ab significantly contributed to the estimated score of working memory (B= -55.85, β= -0.46, p= 0.01), while no correlation was observed between the other 2 types of antibodies and cognitive function.

CONCLUSIONS

The present results indicate the potential of serum anti-GluN1-NT Ab as a biomarker for the severity and prognosis of cognitive dysfunction underlying various psychiatric symptoms in patients with AP. The pathological significance of anti-GluN1-NT Ab needs to be verified in future studies.

An exploratory investigation of antibodies to NMDA-type glutamate receptor subunits in serum and cerebrospinal fluid among psychiatric patients with anti-thyroid antibodies

Introduction

Hashimoto's thyroiditis, which is characterized by anti-thyroid antibodies such as the anti-thyroglobulin (Tg) antibody and anti-thyroid peroxidase (TPO) antibody, is one of the autoimmune diseases associated with psychiatric illnesses. We previously reported a high prevalence of antibodies to N-terminals of N-methyl-D-aspartate (NMDA) type glutamate receptor (GluR) subunits (GluN1-NT and GluN2B-NT2) among psychiatric patients with anti-thyroid antibodies. However, it remains unclear whether the presence of anti-thyroid antibodies influences antibodies to GluN1-NT or GluN2B-NT2 among psychiatric patients. The present study aims to examine antibodies to GluN1-NT and GluN2B-NT2 in psychiatric patients with anti-thyroid antibodies (PPATs) and in those without (non-PPATs).

Material and methods

We recruited psychiatric inpatients aged 20–60 years. Patients were excluded if they had a history of neurological diseases, dementia, developmental disorders, tumors, or autoimmune diseases except autoimmune thyroiditis. The rest of the participants were divided into two groups according to the presence of serum anti-Tg and anti-TPO antibodies. We investigated serum and cerebrospinal fluid (CSF) antibodies to GluN1-NT and GluN2B-NT2 using an enzyme-linked immunosorbent assay (ELISA).

Results

We initially recruited seventy-three psychiatric inpatients. Forty-six patients were excluded because of the exclusion criteria. Eighteen PPATs and nine non-PPATs were ultimately enrolled. We also collected stored sera of eighteen healthy controls (HCs) who were age- and sex-matched with PPATs. The optical densities (ODs) of serum antibodies to GluN1-NT (p = 0.0020) and GluN2B-NT2 (p = 0.039) were significantly higher in PPATs than in HCs. The ODs of CSF antibodies to GluN1-NT (p = 0.030) and GluN2B-NT2 (p = 0.017) as well as the positive ratios of those antibodies were significantly higher in PPATs than in non-PPATs.

Conclusion

Our finding indicates that detecting anti-thyroid antibodies in psychiatric patients would be a clue to consider psychiatric conditions related to antibodies to GluN1-NT/GluN2B-NT2. Further studies focusing on the relationship between PPATs and antibodies to GluN1-NT/GluN2B-NT2 are needed.

Methylprednisolone pulse therapy in 31 patients with refractory epilepsy: A single-center retrospective analysis

PURPOSE

We investigated the efficacy of methylprednisolone pulse therapy (MP) and responder characteristics in patients with refractory epilepsy.

METHODS

We reviewed medical records of our center to identify patients with refractory epilepsy treated with MP other than continuous spikes and waves during slow sleep (CSWS), Landau-Kleffner syndrome (LKS), or Rasmussen's syndrome (RS) between 2004 and 2015. A course of MP consisted of intravenous methylprednisolone (30 mg/kg/day) on three consecutive days. Patients received multiple courses at intervals of four weeks. We examined seizure outcome, developmental outcome, antibodies to N-methyl-d-aspartate (NMDA)-type glutamate receptors (GluRs), cerebral spinal fluid (CSF)-albumin/serum-albumin ratio, and interictal electroencephalograms (EEGs). Responder to MP was defined as maintaining seizure reduction rate (SRR) ≥50% for three months after the first course of MP.

RESULTS

Thirty-one consecutive patients treated with MP at our center were studied. Seizure types were focal onset impaired awareness seizure (FIAS) only (n = 23), FIAS with epileptic spasms (ES) (n = 7), and ES only (n = 1). Responder rate was 32.2% (10/31 patients), and seizure-free rate was 9.7% (3/31). Responders constituted 43.5% of patients without ES. No patient with ES was responder. Behavior and cognition also improved in 6 of 10 responders. History of seizure aggravation after inactivated vaccine before MP was found significantly higher rate in responder patients, comparing with nonresponder patients (p = 0.01).

CONCLUSION

Methylprednisolone pulse therapy may be considered for possible treatment in patients with focal epilepsy with drug-resistant seizures without ES, and it may improve cognitive function and behavioral comorbidities.

Elevated serum anti-NMDA receptor antibody levels in first-episode patients with schizophrenia

Accumulating evidence has shown that N-methyl-D-aspartate (NMDA) glutamate receptors (NMDAR) are implicated in the pathophysiology of neurological and psychiatric disorders, and that patients with NMDAR antibody encephalitis develop psychopathological symptoms. Therefore, we hypothesized that NMDAR antibodies play a key role in the etiology of schizophrenia. In this study, we enrolled 110 first-episode patients with schizophrenia (FEP) and 50 healthy controls (HC). Cognitive function and psychopathology were assessed using the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) Consensus Cognitive Battery (MCCB) and Positive and Negative Syndrome Scale (PANSS), respectively. NMDAR antibody levels were measured using enzyme-linked immunosorbent assay. Our results showed that FEP with schizophrenia exhibited cognitive deficits in all domains of the MCCB and had elevated levels of serum anti-NMDAR antibody compared with the healthy controls (9.2 ± 3.5 vs. 7.3 ± 2.9 ng/ml, t = 3.10, p = 0.002). Furthermore, serum antibody levels were positively correlated with PANSS positive, negative and total score, and inversely correlated with performances of verbal learning and memory, working memory, speed of processing and MCCB total score in the patient group. These results indicate that elevated levels of NMDAR antibody may play a role in the pathogenesis of schizophrenia, leading to NMDAR dysfunction, thereby inducing symptoms of psychosis and cognitive impairment. Therefore, NMDAR antibodies may serve as a biomarker and provide a new avenue for treatment of schizophrenia.

Functional neuroimaging in Rasmussen syndrome

PURPOSE

For a diagnosis of Rasmussen syndrome (RS), clinical course together with electroencephalography (EEG) and magnetic resonance imaging (MRI) findings are considered important, but there are few reports on functional neuroimaging. This study investigated cerebral blood flow (CBF)-single photon emission computed tomography (SPECT), central benzodiazepine receptor (BZR)-SPECT, and fluorine-18 fluorodeoxy glucose-positron emission tomography (FDG-PET) in RS patients, and correlated neuroimaging results with MRI and pathological findings.

METHODS

Twenty-three patients diagnosed with RS according to Bien's (2005) diagnostic criteria (including 12 patients with a histological diagnosis) were studied. CBF-SPECT, BZR-SPECT and FDG-PET images were visually evaluated, and the findings correlated with MRI and histological findings.

RESULTS

Hypoperfusion areas were observed in 16 of 22 patients by interictal CBF-SPECT. Hyperperfusion areas were observed in 10 of 12 patients by ictal CBF-SPECT, which correlated with ictal onset area by ictal EEG (IOAE). In the limited data of BZR-SPECT in nine patients, lowered uptake was detected in all nine patients, including two with no MRI abnormalities. Lowered glucose metabolism was observed in affected areas in all five patients by FDG-PET. Histological examination revealed findings of chronic encephalitis in all 12 patients examined, concomitant with focal cortical dysplasia in five patients.

CONCLUSION

In RS patients, functional neuroimaging reveals clear abnormal findings, even before the appearance of MRI abnormalities. BZR-SPECT and FDG-PET could detect the IOAE efficiently even in the absence of MRI abnormalities, while interictal CBF-SPECT occasionally failed to detect IOAE if MRI was normal. Based on BZR-SPECT, refractory epileptic seizures in RS may suggest possible impairment of inhibitory neurons.

Seizures and risk of epilepsy in autoimmune and other inflammatory encephalitis

PURPOSE OF REVIEW

The aim of this study was to assess the seizure manifestations and risk of epilepsy in encephalitis associated with antibodies against neuronal cell-surface (autoimmune encephalitis) or myelin-associated antigens, and to review several chronic epileptic disorders, including Rasmussen's encephalitis, fever-induced refractory epileptic syndromes (FIRES) and new-onset refractory status epilepticus (NORSE).

RECENT FINDINGS

Seizures are a frequent manifestation of autoimmune encephalitis. Some autoimmune encephalitis may associate with characteristic features: faciobrachial dystonic seizures (anti-LGI1 encephalitis), electroencephalogram extreme delta brush (anti-NMDAR) or multifocal FLAIR-MRI abnormalities (anti-GABAAR). In anti-LGI1 encephalitis, cortical, limbic and basal ganglia dysfunction results in different types of seizures. Autoimmune encephalitis or myelin-antibody associated syndromes are often immunotherapy-responsive and appear to have a low risk for chronic epilepsy. In contrast patients with seizures related to GAD65-antibodies (an intracellular antigen) frequently develop epilepsy and have suboptimal response to treatment (including surgery). Rasmussen's encephalitis or FIRES may occur with autoantibodies of unclear significance and rarely respond to immunotherapy. A study of patients with NORSE showed that 30% developed chronic epilepsy.

SUMMARY

Although seizures are frequent in all types of autoimmune encephalitis, the risk for chronic epilepsy is dependent on the antigen: lower if located on the cell-surface, and higher if intracellular. For other disorders (Rasmussen's encephalitis, FIRES, NORSE), the prognosis remains poor.

Anti-N-Methyl-D-Aspartate Receptor Encephalitis and Rasmussen-like Syndrome: An Association?

BACKGROUND

N-methyl-D-aspartate (NMDA) receptor encephalitis is an immune-mediated condition that has a broad spectrum of manifestations, including seizures, coma, psychosis, and focal neurological deficits. Although usually a diffuse process, unihemispheric involvement mimicking early stages of Rasmussen encephalitis can occur. Rasmussen's encephalitis is a unique syndrome characterized by progressive hemiplegia, drug-resistant focal epilepsy, cognitive decline, and hemispheric brain atrophy contralateral to the hemiplegia.

PATIENT DESCRIPTION

We describe a two-year-old girl with progressive right weakness and epilepsia partialis continua, concerning for early Rasmussen's encephalitis, who tested positive for anti-NMDA receptor antibodies. She experienced complete clinical recovery after immunotherapy. Anti-NMDA receptor antibodies were absent at three weeks and again at one year after the first treatment of intravenous immunoglobulin.

CONCLUSIONS

There are few reports of Rasmussen-like encephalitis in individuals with anti-NMDA receptor antibody positivity. Thus the clinical significance of this association is yet to be determined. In addition, several other antibodies have been documented in individuals with Rasmussen encephalitis. The lack of a consistently reported antibody in Rasmussen encephalitis patients and the temporary nature of the anti-NMDA receptor antibody in our patient raise the following question: Is the presence of anti-NMDA receptor antibodies the cause of the symptoms or secondary to the pathogenic process?

Antibodies against peptides of NMDA-type GluR in cerebrospinal fluid of patients with epileptic spasms

OBJECTIVE

We investigated the contribution of antibodies against N-methyl-d-aspartate (NMDA)-type glutamate receptor (GluR) in cerebrospinal fluid (CSF) to the clinical features of patients with epileptic spasms (ES).

METHODS

CSF samples were collected from 33 patients with ES with median (range) age 1.8 (0.2-8.5) years. Thirty patients without ES with 3.5 (0.5-7.0) years were also studied as disease controls. The CSF levels of antibodies against peptides of NMDA-type GluR subunits (GluN2B & GluN1) were measured by enzyme-linked immunosorbent assay.

RESULTS

The levels of antibodies against the n-terminal of GluN2B (GluN2B-NT2), c-terminal of GluN2B (GluN2B-CT) and n-terminal of GluN1 (GluN1-NT), were significantly higher in patients with ES than in disease controls (p < 0.01, p < 0.01 & p = 0.03). Levels of antibodies to GluN2B-NT2 & CT were not related with ACTH therapy nor conventional CSF factors (cell counts, protein level, etc). Levels of antibodies to GluN2B-NT2 & CT showed evidence of correlation within a linear regression model with intervals from the onset to the examination of CSF until 25 months (p = 0.01 & p = 0.01). The correlation was significant in patients with unknown cause (p = 0.01). Five of 33 patients (four unknown cause & one chromosomal anomaly) had higher level of antibodies to GluN2B-NT2 exceeding mean + 1 SD of all ES patients, and they had poor motor (score 0) and cognitive outcomes (score 0 or 1).

CONCLUSION

The CSF level of antibodies against GluN2B in ES patients with unknown cause was estimated to increase after onset. We hypothesize that some ES patients may have immune process after the onset of ES.

Immunological studies of cerebrospinal fluid from patients with CNS symptoms after human papillomavirus vaccination

In 32 patients with prolonged central nervous system symptoms after human papillomavirus (HPV) vaccination, we measured conventional and immunological markers in cerebrospinal fluid (CSF) and compared with the levels in disease controls. Our studies revealed significantly decreased chloride and neuron-specific enolase (NSE) levels in CSF of patients with CNS symptoms after HPV vaccination compared to disease controls. IL-4, IL-13, and CD4(+) T cells increased significantly in patients, and IL-17 increased significantly from 12 to 24months after symptom onset. Chemokines (IL-8 and MCP-1) were also elevated, but CD8(+) T cells, PDGF-bb and IL-12 were reduced. Antibodies to GluN2B-NT2, GluN2B-CT and GluN1-NT increased significantly. These results suggest biological, mainly immunological, changes in the CSF of patients after HPV vaccination.