Anti-NMDAR encephalitis in a child with long impaired consciousness and persistent antibodies: a case report and mini review.

We described a challenging case of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis in a young girl. Despite enduring months of reduced consciousness with ongoing antibody presence, she ultimately exhibited remarkable improvement within a 5-year follow-up period. Additionally, we conducted a concise review of relevant literature on anti-NMDAR encephalitis, with a specific focus on anti-NMDAR antibodies. Our findings enhance the clinical comprehension of anti-NMDAR encephalitis and offer valuable insights to clinicians for its management.

Aberrant functional hubs and related networks attributed to cognitive impairment in patients with anti­N­methyl­D­aspartate receptor encephalitis.

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis results in severe neuropsychiatric symptoms and persistent cognitive impairment; however, the underlying mechanism is still not fully understood. The present study utilized the degree centrality (DC), functional connectivity (FC) and multivariate pattern analysis (MVPA) to further explore neurofunctional symptoms in patients with anti-NMDAR encephalitis. A total of 29 patients with anti-NMDAR encephalitis and 26 healthy controls (HCs) were enrolled for neuropsychological assessment and resting-state functional MRI (rs-fMRI) scans. DC, FC and MVPA were examined to investigate cerebral functional activity and distinguish neuroimaging characteristics between the patient and HC groups based on the rs-fMRI data. Compared with the HCs, the patients exhibited cognitive deficits, anxiety and depression. In the DC analysis, the patients exhibited significantly decreased DC strength in the left rectus gyrus, left caudate nucleus (LCN) and bilateral superior medial frontal gyrus, as well as increased DC strength in the cerebellar anterior lobe, compared with the HCs. In the subsequent FC analysis, the LCN showed decreased FC strength in the bilateral middle frontal gyrus and right precuneus. Furthermore, correlation analysis indicated that disrupted cerebral functional activity was significantly correlated with the alerting effect and Hamilton Depression Scale score. Using DC maps and receiver operating characteristic curve analysis, the MVPA classifier exhibited an area under curve of 0.79, and the accuracy classification rate was 76.36%, with a sensitivity of 79.31% and a specificity of 78.18%. The present study revealed that the disrupted functional activity of hub and related networks in the cerebellum, including the default mode network and executive control network, contributed to deficits in cognition and emotion in patients with anti-NMDAR encephalitis. In conclusion, the present study provided imaging evidence and primary diagnostic markers for pathological and compensatory mechanisms of anti-NMDAR encephalitis, with the aim of improving the understanding of this disease.

Efficacy of steroid therapy in the acute stage of anti-NMDAR and anti-MOG antibody overlapping encephalitis: a case report and literature review.

Background: Recently, cases of overlapping encephalitis caused by anti-N-methyl-D-aspartate receptor (anti-NMDAR) and anti-myelin oligodendrocyte glycoprotein (MOG) antibodies have been reported, and their clinical characteristics are gradually becoming clear. Acute-phase treatment typically involves the use of steroids, and although some studies have suggested that steroids can be effective, the extent of their efficacy has not yet been fully explored. Case presentation: We present the case of a 25-year-old man with anti-NMDAR and anti-MOG antibody overlapping encephalitis who showed considerable improvement after steroid treatment. To gain a deeper understanding of the efficacy of steroids in managing this condition, we conducted a literature review of cases of anti-NMDAR and anti-MOG antibody double-positive encephalitis that were treated with steroids during the acute phase. Thirteen cases were analyzed, including a new case diagnosed at our hospital. All patients showed improvement after receiving steroid treatment in the acute phase. Ten patients did not have any sequelae, and nine of them showed a rapid or major response during the acute phase. In contrast, three patients experienced sequelae (mild cognitive decline, visual impairment, and memory impairment, respectively), with their response to steroids in the acute phase being slow or limited. Relapses occurred in five patients, in one patient during steroid tapering, and in another two patients after cessation of steroids. Conclusion: Steroid therapy can be effective in the acute stage of anti-NMDAR and anti-MOG antibody overlapping encephalitis. A positive prognosis may be expected in patients who experience substantial improvement with steroid therapy during the acute phase.

Inhibition of NLRP3 inflammasome alleviates cognitive deficits in a mouse model of anti-NMDAR encephalitis induced by active immunization.

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a neurological disorder, characterized by cognitive deficits as one of its vital features. The nucleotide-binding oligomerization domain-like receptor (NLRP3) inflammasome is a key contributor to neuroinflammation and cognitive deficits in neurological diseases. However, the underlying mechanism of anti-NMDAR encephalitis remains unclear, and the biological function of the NLRP3 inflammasome in this condition has not been elucidated. In this study, a mouse model of anti-NMDAR encephalitis was induced by active immunization with the GluN1356-385 peptide (NEA model). The NLRP3 inflammasome in the hippocampus and temporal cortex was investigated using real-time quantitative PCR (RT-qPCR), western blotting, and immunofluorescence staining. The impact of MCC950 on cognitive function and NLRP3 inflammation was assessed. Confocal immunofluorescence staining and Sholl analysis were employed to examine the function and morphology of microglia. In the current study, we discovered overactivation of the NLRP3 inflammasome and an enhanced inflammatory response in the NEA model, particularly in the hippocampus and temporal cortex. Furthermore, significant cognitive dysfunction was observed in the NEA model. While, MCC950, a selective inhibitor of the NLRP3 inflammasome, sharply attenuated the inflammatory response in mice, leading to mitigated cognitive deficits of mice and more regular arrangements of neurons and reduced number of hyperchromatic cells were also observed in the hippocampus area. In addition, we found that the excess elevation of NLRP3 inflammasome was mainly expressed in microglia accompanied with the overactivation of microglia, while MCC950 treatment significantly inhibited the increased number and activated morphological changes of microglia in the NEA model. Altogether, our study reveals the vital role of overactivated NLRP3 signaling pathway in aggravating the inflammatory response and cognitive deficits and the potential protective effect of MCC950 in anti-NMDAR encephalitis. Thus, MCC950 represents a promising strategy for anti-inflammation in anti-NMDAR encephalitis and our study lays a theoretical foundation for it to become a clinically targeted drug.

Aberrant Brain Networks and Relative Band Power in Patients with Acute Anti-NMDA Receptor Encephalitis: A Study of Resting-State EEG.

OBJECTIVE: The alterations of the functional network (FN) in anti-N-methyl-Daspartate receptor (NMDAR) encephalitis have been recognized by functional magnetic resonance imaging studies. However, few studies using the electroencephalogram (EEG) have been performed to explore the possible FN changes in anti-NMDAR encephalitis. In this study, the aim was to explore any FN changes in patients with anti-NMDAR encephalitis. METHODS: Twenty-nine anti-NMDAR encephalitis patients and 29 age- and gender-matched healthy controls (HC) were assessed using 19-channel EEG examination. For each participant, five 10-second epochs of resting state EEG with eyes closed were extracted. The cortical source signals of 84 Brodmann areas were calculated using the exact low resolution brain electromagnetic tomography (eLORETA) inverse solution by LORETA-KEY. Phase Lag Index (PLI) matrices were then obtained and graph and relative band power (RBP) analyses were performed. RESULTS: Compared with healthy controls, functional connectivity (FC) in the delta, theta, beta 1 and beta 2 bands significantly increased within the 84 cortical source signals of anti-NMDAR encephalitis patients (p < 0.05) and scalp FC in the alpha band decreased within the 19 electrodes. Additionally, the anti-NMDAR encephalitis group exhibited higher local efficiency and clustering coefficient compared to the healthy control group in the four bands. The slowing band RBP increased while the fast band RBP decreased in multiple-lobes and some of these changes in RBP were correlated with the modified Rankin Scale (mRS) and Mini-mental State Examination (MMSE) in anti-NMDAR encephalitis patients. CONCLUSIONS: This study further deepens the understanding of related changes in the abnormal brain network and power spectrum of anti-NMDA receptor encephalitis. The decreased scalp alpha FC may indicate brain dysfunction, while the increased source beta FC may indicate a compensatory mechanism for brain function in anti-NMDAR encephalitis patients. These findings extend understanding of how the brain FN changes from a cortical source perspective. Further studies are needed to detect correlations between altered FNs and clinical features and characterize their potential value for the management of anti-NMDAR encephalitis.

Abnormal global and local connectivity in patients with anti-N-methyl-D-aspartate receptor encephalitis: A resting-state functional MRI study.

OBJECTIVE: We decided to investigate the changes of global and local connectivity in anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis patients based on eigenvector centrality (EC) and regional homogeneity (ReHo). We sought new biomarkers to identify the patients based on multivariate pattern analysis (MVPA). METHODS: Functional MRI (fMRI) was performed on all participants. EC, ReHo and MVPA were used to analyze the fMRI images. The correlation between the global or local connectivity and neuropsychology tests was detected. RESULTS: The MoCA scores of the patients were lower than those of the healthy controls (HCs), while the HAMD24 and HAMA scores of the patients were higher than those of the HCs. Increased EC values in the right calcarine (CAL.R) and decreased EC values in the right putamen (PUT.R) distinguished these subjects with anti-NMDAR encephalitis from HCs. The higher ReHo values in the left postcentral gyrus (PoCG.L) were detected in the patients. The correlation analysis showed that the EC values in the PUT.R were negatively correlated with HAMD24 and HAMA scores, while the ReHo values in the PoCG.L were negatively correlated with MoCA scores. Better classification performance was reached in the EC-based classifier (AUC = 0.80), while weaker classification performance was achieved in the ReHo-based classifier (AUC = 0.74) or the classifier based on EC and ReHo (AUC = 0.74). The brain areas with large weights were located in the frontal lobe, parietal lobe, cerebellum and basal ganglia. CONCLUSION: Our findings suggest that abnormal global and local connectivity may play an important part in the pathophysiological mechanism of neuropsychiatric symptoms in the anti-NMDAR encephalitis patients. The EC-based classifier may be better than the ReHo-based classifier in identifying anti-NMDAR encephalitis patients.

Anti-N-Methyl-D-Aspartate Receptor Encephalopathy in a Young Female.

Widely distributed in the central nervous system (CNS), N-methyl-D-aspartate receptors (NMDARs) are believed to be involved in long-term potentiation, essential in regulating and forming memory. This condition primarily occurs in young females because of autoantibodies forming against the N-methyl-D-aspartate receptor-1 (NR1) or N-methyl-D-aspartate receptor-2 (NR2) subunits of NMDAR in the CNS, ultimately portraying a unique psychoneurological phenomenon. Patients with antibodies against NMDAR present with a combination of neurological and psychiatric signs and symptoms. This article presents a case of a young female with no significant past medical, psychological, or surgical history. While being previously diagnosed with acute psychosis, upon arrival at the emergency department (ED), she also displayed an acute decline in judgment, hallucinations, severe agitation, and peculiar behavior, prompting family members to seek medical attention. Consequently, she was evaluated for metabolic and infectious encephalopathy. Following a thorough examination and extensive laboratory imaging, the patient was found to have NMDAR antibody encephalopathy. After dedicated treatment, her two-month follow-up presented a complete resolution of symptoms.

Case report: Isolated brainstem-cerebellar symptoms in a patient with anti-NMDA receptor encephalitis.

Cerebellar ataxia is an uncommon and atypical manifestation of anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, often accompanied by seizures, psychiatric symptoms, and cognitive deficits. Previous cases of isolated brainstem-cerebellar symptoms in patients with anti-NMDAR encephalitis have not been documented. This report presents a case of anti-NMDAR encephalitis in which the patient exhibited cerebellar ataxia, nystagmus, diplopia, positive bilateral pathological signs, and hemiparesthesia with no other accompanying symptoms or signs. The presence of positive CSF anti-NMDAR antibodies further supports the diagnosis. Other autoantibodies were excluded through the use of cell-based assays. Immunotherapy was subsequently administered, leading to a gradual recovery of the patient.

Exploring the neuroprotective role of artesunate in mouse models of anti-NMDAR encephalitis: insights from molecular mechanisms and transmission electron microscopy.

BACKGROUND: The pathway involving PTEN-induced putative kinase 1 (PINK1) and PARKIN plays a crucial role in mitophagy, a process activated by artesunate (ART). We propose that patients with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis exhibit insufficient mitophagy, and ART enhances mitophagy via the PINK1/PARKIN pathway, thereby providing neuroprotection. METHODS: Adult female mice aged 8-10 weeks were selected to create a passive transfer model of anti-NMDAR encephalitis. We conducted behavioral tests on these mice within a set timeframe. Techniques such as immunohistochemistry, immunofluorescence, and western blotting were employed to assess markers including PINK1, PARKIN, LC3B, p62, caspase3, and cleaved caspase3. The TUNEL assay was utilized to detect neuronal apoptosis, while transmission electron microscopy (TEM) was used to examine mitochondrial autophagosomes. Primary hippocampal neurons were cultured, treated, and then analyzed through immunofluorescence for mtDNA, mtROS, TMRM. RESULTS: In comparison to the control group, mitophagy levels in the experimental group were not significantly altered, yet there was a notable increase in apoptotic neurons. Furthermore, markers indicative of mitochondrial leakage and damage were found to be elevated in the experimental group compared to the control group, but these markers showed improvement following ART treatment. ART was effective in activating the PINK1/PARKIN pathway, enhancing mitophagy, and diminishing neuronal apoptosis. Behavioral assessments revealed that ART ameliorated symptoms in mice with anti-NMDAR encephalitis in the passive transfer model (PTM). The knockdown of PINK1 led to a reduction in mitophagy levels, and subsequent ART intervention did not alleviate symptoms in the anti-NMDAR encephalitis PTM mice, indicating that ART's therapeutic efficacy is mediated through the activation of the PINK1/PARKIN pathway. CONCLUSIONS: At the onset of anti-NMDAR encephalitis, mitochondrial damage is observed; however, this damage is mitigated by the activation of mitophagy via the PINK1/PARKIN pathway. This regulatory feedback mechanism facilitates the removal of damaged mitochondria, prevents neuronal apoptosis, and consequently safeguards neural tissue. ART activates the PINK1/PARKIN pathway to enhance mitophagy, thereby exerting neuroprotective effects and may achieve therapeutic goals in treating anti-NMDAR encephalitis.

A case of NMDAR Encephalitis with muscular pain as the main presentation.

BACKGROUND: Persistent somatoform pain disorder (PSPD) is often the initial diagnosis in patients seeking treatment in psychiatric departments, making it challenging to consider organic nervous system diseases. However, autoimmune encephalitis can present with atypical initial symptoms, leading to misdiagnosis or missed diagnosis. Lumbar puncture, with antibody support, plays a crucial role in diagnosing autoimmune encephalitis. CASE PRESENTATION: This report describes a 40-year-old male adult patient who was initially diagnosed with persistent somatoform pain disorder in 2022. The patient reported a reduction in pain while resting on his back. There were no fever or relevant medical history. Despite 8 months of symptomatic treatment, the symptoms did not improve. Moreover, the patient developed confusion, gibberish speech, non-cooperation during questioning, and increased frequency and amplitude of upper limb convulsions. Lumbar puncture revealed elevated protein levels and protein-cell dissociation. The autoimmune encephalitis antibody NMDAR (+) was detected, leading to a diagnosis of autoimmune encephalitis (NMDAR). CONCLUSION: Autoimmune encephalitis (NMDAR), starting with persistent somatoform pain (PSPD), often presents with atypical symptoms and can be easily misdiagnosed. Therefore, it is important to consider the possibility of organic nervous system disease in time, and to test serum or cerebrospinal fluid antibodies to rule out organic nervous system disease after symptomatic treatment of mental disorders is ineffective. This approach facilitates the early diagnosis of autoimmune encephalitis and other underlying organic neurological disorders.

Anti-NMDA Receptor Encephalitis Related to Renal Cell Carcinoma: A Case Report.

Anti-NMDA receptor (NMDAR) encephalitis is characterized by a well-defined neuropsychiatric syndrome and CSF antibodies against the GluN1 subunit of the NMDAR. 40% of cases are related to underlying tumors, the vast majority ovarian teratomas (94%). We report a case of anti-NMDAR encephalitis associated with renal cell carcinoma (RCC). A 20-year-old female presented to the ED with behavioral changes, involuntary movements, tachycardia, and alternating obtundation with agitation which progressed over 3 weeks. Involuntary movements were severe, requiring intubation and sedation for control, and were accompanied by rhabdomyolysis. Brain MRI showed bilateral mesiotemporal T2/FLAIR hyperintensities. Anti-NMDAR antibodies were present in the serum (1:640) and CSF (1:320). Malignancy screening revealed a renal mass concerning for RCC, which was confirmed upon resection. She was started on high dose IV methylprednisolone and plasmapheresis, followed by rituximab. Lack of response led to escalating immunotherapy with cyclophosphamide. Clinical course was complicated by prolonged ICU admission, prolonged sedation, severe dysautonomia and bacteremia. Improvement began 2 months after immunotherapy, and she was discharged to rehabilitation 100 days after admission with mild neuropsychiatric symptoms. Repeat malignancy screenings, including whole-body imaging and transvaginal ultrasound were consistently negative. Herein, we describe a case of definite anti-NMDAR encephalitis in the setting of newly diagnosed RCC. This case illustrates how tumors other than ovarian teratomas may act as immunological triggers, as well as the complex and prolonged symptomatic and immunosuppressive therapies required in severe presentations of anti-NMDAR encephalitis.

Anti-N-methyl-D-aspartate Receptor Encephalitis in People Living with HIV: Case Report and Literature Review.

With the increase in the number of cases of autoimmune encephalitis (AE), the cerebrospinal fluid (CSF) of people living with HIV (PLWH) showing abnormal behavior, cognitive impairment or abnormal movements should be actively screened for the antibody panel of AE. Early recognition and treatment can prevent severe seizures or coma and markedly improve the prognosis of patients. The first-line immunotherapy for AE includes intravenous methylprednisolone and immunoglobulin. However, whether long-time immunosuppressive maintenance therapy is needed is debated. For PLWH, immunosuppressive therapy and even steroids could be more challenging. Here, we review and summarize the clinical characteristics often reported cases and report one case from our center to improve the diagnosis and treatment of anti-N-methyl-D-aspartate receptor encephalitis in PLWH.

Low-Grade Glioma within Mature Cystic Teratoma in a Patient with Anti-N-Methyl-D-Aspartate Receptor Encephalitis: A Case Report.

Introduction: Mature cystic teratoma (MCT) is a common type of ovarian tumors that can, in rare cases, undergo malignant transformation. It has been discovered that MCT patients may experience psychiatric symptoms due to the presence of anti-N-methyl-D-aspartate receptor (NMDAR) antibodies, which is the underlying cause of autoimmune encephalitis. Here, we present the first documented case of a patient with anti-NMDAR encephalitis who also had a morphology of low-grade glioma within MCT. Case Report: A 45-year-old woman presented with seizures, altered consciousness, abnormal NMDAR antibody IgG titers, and abnormal brain MRI findings confirm the diagnosis of anti-NMDAR encephalitis. Physical examination revealed an oval mixed echo mass measuring 54 × 37 mm in the left adnexal area on ultrasound of the uterine appendage. The patient underwent laparoscopic left ovarian and fallopian tube resection. The pathological gross examination revealed a pile of grayish-red cystic and solid fragmented tissue measuring 7 × 6 × 2.2 cm. Histological examination revealed characteristic components of MCT. Furthermore, the solid component of the gross tissue showed proliferative and densely arranged astrocytes with cellular atypia, which were positive for GFAP and Olig-2, negative for IDH1 and EMA. And the Ki67 index was approximately 10%, suggesting the presence of low-grade glioma lesions. The patient was diagnosed with malignant transformation of MCT into a morphology of low-grade glioma, not otherwise specified. After the removal of the ovarian tumor, the patient's psychiatric symptoms improved. Conclusions: Low-grade glioma within MCT is a rare occurrence, and the presence of this malignant transformation in patients with anti-NMDAR encephalitis is even more uncommon.

Pathogenesis and immunopathology of paraneoplastic disorders.

Paraneoplastic neurologic syndromes (PNS) represent a rare group of immune-mediated complications associated with an underlying tumor. Ectopic protein expression in neoplastic cells or an aberrant immune regulation in the course of hematooncologic diseases or thymomas trigger an autoimmune response that may affect any part of the central and/or peripheral nervous system. Recent advances in drug therapies as well as novel animal models and neuropathologic studies have led to further insights on the immune pathomechanisms of PNS. Although the syndromes share common paths in pathogenesis, they may differ in the disease course, prognosis, and therapy targets, depending on the localization and type of antibody epitope. Neuropathologic hallmarks of PNS associated with antibodies directed against intracellular epitopes are characterized by T cell-dominated inflammation, reactive gliosis including microglial nodules, and neuronal degeneration. By contrast, the neuropathology of cell surface antibody-mediated PNS strongly depends on the targeted antigen and varies from B cell/plasma cell-dominated inflammation and well-preserved neurons together with a reduced expression of the target antigen in anti-NMDAR encephalitis to irreversible Purkinje cell loss in anti-P/Q-type VGCC antibody-associated paraneoplastic cerebellar degeneration. The understanding of different pathomechanisms in PNS is important because they strongly correspond with therapy response and prognosis, and should guide treatment decisions.

Analysis of characteristics of movement disorders in patients with anti-N-methyl-D-aspartate receptor encephalitis.

Objective: Movement disorders (MDs) are common in anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis but are poorly studied. This study aimed to investigate the clinical characteristics of MDs and the clinical differences between patients with and without MDs in anti-NMDAR encephalitis. Methods: A retrospective study was conducted on patients with anti-NMDAR encephalitis who were first diagnosed and treated in the First People's Hospital of Yunnan Province from January 2017 to September 2022. According to the presence or absence of MDs, all patients were divided into two groups, and the clinical manifestations, auxiliary examinations, and prognosis of the two groups were compared. Patients in the MDs group were further subgrouped by different ages (<12 years, 12-17 years, and ≥ 18 years) and genders, and the prevalence of each MD was compared in different age and gender groups. Results: (1) In our study there were 64 patients, of whom 76.6% (49/64) presented with MDs; the median age of onset in patients with MDs was 21 (15,35) years and 65.3% (32/49) were female. The three most common MDs were orofacial dyskinesia (OFLD) (67.3%), dystonia (55.1%), and stereotypies (34.7%). Patients <12 years were more likely to experience chorea than patients in other age groups (p = 0.003). (2) Compared with the non-MDs group, patients in the MDs group showed higher rates of prodromal manifestations, autonomic dysfunction, consciousness disorders, as well as pulmonary infection and gastrointestinal dysfunction (all p < 0.05). Peripheral blood neutrophil to lymphocyte ratio (NLR) (p = 0.014), the proportion of cerebrospinal fluid (CSF) NMDAR antibody titers ≥1:32 (p = 0.047), ICU admission rate (p = 0.04), length of stay (p = 0.007), maximum mRS score in the course of disease (p = 0.001) and mRS score at discharge (p = 0.006) in the MDs group were significantly higher than the non-MDs group. Conclusion: MDs associated with anti-NMDAR encephalitis were predominantly hyperkinetic. Chorea occurred more commonly in patients aged <12 years. Patients with MDs were prone to autonomic dysfunction, consciousness disorders, pulmonary infection, and gastrointestinal dysfunction; they had more intense inflammation, more severe disease, and a poorer short-term prognosis.

Clinical features of adult patients with positive NMDAR-IgG coexisting with MOG-IgG.

INTRODUCTION: This study was designed to analyze clinical and radiographic features of adult patients coexisting with NMDAR-IgG and MOG-IgG. METHODS: Eleven adult patients coexisting with NMDAR-IgG and MOG-IgG were collected from Xiangya Hospital, Central South University, between June 2017 and December 2021. Fifty-five patients with anti-NMDAR encephalitis and 49 with MOG-AD were served as controls. RESULTS: Onset age was 27 (IQR 20-34) years old. Seizures and psychotic symptoms were prominent symptoms. Ten of eleven patients presented abnormal T2/FLAIR hyperintensity, mainly involving the cortex, brainstem, and optic nerve. Compared with the NMDAR IgG ( +)/MOG IgG ( -) group, the NMDAR IgG ( +)/MOG IgG ( +) group showed more ataxia symptoms (27.3% vs. 3.6%, P = 0.037), while more T2/FLAIR hyperintensity lesions were found in the brainstem (54.5% vs. 7.3%, P < 0.001) and optic nerve (27.3% vs. 1.8%, P = 0.011) with more abnormal MRI patterns (90.9% vs. 41.8%, P = 0.003). In comparison with the NMDAR IgG ( -)/MOG IgG ( +) group, the NMDAR IgG ( +)/MOG IgG ( +) group had more seizures (72.7% vs. 24.5%, P = 0.007) and mental symptoms (45.5% vs. 0, P < 0.001). The NMDAR IgG ( +)/MOG IgG ( +) group tended to be treated with corticosteroids alone (63.6% vs. 20.0%, P = 0.009), more prone to recur (36.5% vs. 7.3%, P = 0.028) and lower mRS score (P = 0.036) at the last follow-up than pure anti-NMDAR encephalitis. CONCLUSION: The symptoms of the NMDAR IgG ( +)/MOG IgG ( +) group were more similar to anti-NMDAR encephalitis, while MRI patterns overlapped more with MOG-AD. Detecting both NMDAR-IgG and MOG-IgG maybe warranted in patients with atypical encephalitis symptoms and demyelinating lesions in infratentorial regions.

Rapamycin alleviates mitochondrial dysfunction in anti-NMDAR encephalitis mice.

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most prevalent forms of autoimmune encephalitis, characterized by a series of neurological and psychiatric symptoms, including cognitive impairment, seizures and psychosis. The underlying mechanism of anti-NMDAR encephalitis remains unclear. In the current study, the mouse model of anti-NMDAR encephalitis with active immunization was performed. We first uncovered excessive mitochondrial fission in the hippocampus and temporal cortex of anti-NMDAR encephalitis mice, indicated by elevated level of Phospho-DRP1 (Ser616) (p-Drp1-S616). Moreover, blockade of the autophagic flux was also demonstrated, leading to the accumulation of fragmented mitochondria, and elevated levels of mitochondrial reactive oxygen species (mtROS) and mitochondrial DNA (mtDNA) in anti-NMDAR encephalitis. More importantly, we found that the mTOR signaling pathway was overactivated, which could aggravate mitochondrial fission and inhibit autophagy, resulting in mitochondrial dysfunction. While rapamycin, the specific inhibitor of the mTOR signaling pathway, significantly alleviated mitochondrial dysfunction by inhibiting mitochondrial fission and enhancing autophagy. Levels of mtROS and mtDNA were markedly reduced after the treatment of rapamycin. In addition, rapamycin also significantly alleviated cognitive dysfunction and anxious behaviors found in anti-NMDAR encephalitis mice. Thus, our study reveals the vital role of mitochondrial dysfunction in pathological mechanism of anti-NMDAR encephalitis and lays a theoretical foundation for rapamycin to become a clinically targeted drug for anti-NMDAR encephalitis.

Anti-NMDA-receptor encephalitis and concurrent neuroborreliosis misdiagnosed for post-COVID-19-syndrome: a case report.

We present a case of a 42-year-old woman with paraneoplastic anti-N-Methyl-D-Aspartat (NMDA)-receptor encephalitis and concurrent neuroborreliosis that was initially misdiagnosed as post-COVID-19 syndrome. Clinically, the patient presented with a range of chronic and subacute neuropsychiatric symptoms and recalled a tick bite weeks prior to admission. The patient had undergone psychiatric and complementary medical treatments for 1 year before admission and was initially diagnosed with post-COVID-19 syndrome. Admission was performed because of acute worsening with fever, confusion, and unsteady gait. Cerebrospinal fluid (CSF) analysis revealed pleocytosis with elevated borrelia Immunoglobulin M (IgM) and Immunoglobulin M (IgG) CSF/blood antibody indices, indicating acute neuroborreliosis. Anti-NMDA receptor antibodies were identified in the CSF via a cell-based assay and were confirmed by an external laboratory. Other paraneoplastic antibodies were ruled out during in-house examination. Cranial Magnetic resonance imaging (MRI) revealed basal meningitis, rhomb- and limbic encephalitis. A subsequent pelvic Computer tomography (CT) scan identified an ovarian teratoma. The patient's clinical condition improved dramatically with antibiotic treatment and plasmapheresis, the teratoma was surgically removed and she was started on rituximab. Our case highlights that amidst the prevailing focus on COVID-19-related health concerns, other well-established, but rare neurological conditions should not be neglected. Furthermore, our case illustrates that patients may suffer from multiple, concurrent, yet pathophysiologically unrelated neuroinflammatory conditions.

Performance of assessment tools in predicting neural autoantibody positivity in patients with seizures.

BACKGROUND: The identification of patients with seizures of unknown etiology who would benefit from neural antibody testing necessitates effective assessment tools. The study aimed to compare the performance of the Antibody Prevalence in Epilepsy and Encephalopathy (APE2) score and the "Obvious" Indications for Neural Antibody Testing in Epilepsy or Seizures (ONES) checklist. We also intended to evaluate whether the performance of the tools varied by types of antibody. METHODS: Patients diagnosed with epilepsy, seizures, or status epilepticus of unknown etiology at West China Hospital from January 2019 to December 2021 were included. Paired serum/cerebrospinal fluid samples were analyzed for antineuronal and antiglial antibodies. The APE2 score and ONES checklist were applied, and their outcomes were compared to laboratory antibody test results. Possible false positive neuronal antibody results were excluded in sensitivity/specificity analysis reasonably. RESULTS: A total of 113 antibody-positive and 159 antibody-negative patients were enrolled in sensitivity/specificity analysis. The ONES checklist showed superior sensitivity than APE2 score (95.6 % vs.79.6 %, P < 0.001). Specificity was not statistically different (60.4 % vs. 57.9 %, P = 0.557). The negative predictive value (NPV) of ONES checklist was higher than that of APE2 score (94.8 % vs 80.7 %, P < 0.001). The positive predictive value of them was not statistically different (61.7 % vs 58.8 %, P = 0.557). APE2 score exhibited lower sensitivity for predicting LGI-Abs (52.9 % vs. 80.3 %, P = 0.022) compared to NMDAR-Abs. Similarly, ONES checklist showed lower sensitivity for LGI1-Abs than NMDAR-Abs (82.4 % vs. 100.0 %, P = 0.009). CONCLUSIONS: The ONES checklist demonstrates superior sensitivity for neural antibody positivity than APE2 score. Specificity of the two assessment tools was similar. ONES checklist performed better NPV than the APE2 score. Both assessment tools performed less well in predicting the presence of LGI1- Abs when compared to NMDAR-Abs.

A peptide from the Japanese encephalitis virus failed to induce the production of anti-N-methyl-d-aspartate receptor antibodies via molecular mimicry in mice.

Background: The development of anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis following viral encephalitis, such as Japanese encephalitis, has received increasing attention in recent years. However, the mechanism of anti-NMDAR antibody production following Japanese encephalitis has not been explored. Methods: A peptide from the Japanese encephalitis virus (JEV), which shares a similar amino acid sequence with GluN1, was identified by sequence comparison. We then explored whether active subcutaneous immunization with the JEV peptide could induce the production of anti-NMDAR antibodies and related pathophysiological and behavioral changes in mice. In addition, a published active immune model of anti-NMDAR encephalitis using a GluN1 peptide was used as the positive control. Results: A 6-amino-acid sequence with 83 % similarity between the envelope protein of the JEV (HGTVVI) and GluN1 (NGTHVI) was identified, and the sequence included the N368/G369 region. Active immunization with the JEV peptide induced a substantial and specific immune response in mice. However, anti-NMDAR antibodies were not detected in the serum of mice immunized with the JEV peptide by ELISA, CBA, and TBA. Moreover, mice immunized with the JEV peptide presented no abnormities related to anti-NMDAR antibodies according to western blotting, patch clamp, and a series of behavioral tests. In addition, active immunization with a recently reported GluN1 peptide failed to induce anti-NMDAR antibody production in mice. Conclusions: In this study, the attempt of active immunization with the JEV peptide to induce the production of anti-NMDAR antibodies via molecular mimicry failed. The pathogenesis of anti-NMDAR encephalitis following Japanese encephalitis remains to be elucidated.