Anti-NMDA-receptor encephalitis: case series and analysis of the effects of antibodies

Cognitive outcomes and performance of patients diagnosed and treated for N-Methyl-D-Aspartate receptor antibody-mediated (NMDAR) encephalitis compared with patients with schizophrenia and healthy controls

BACKGROUND

Cognitive dysfunction may be a sequelae of N-Methyl-D-Aspartate receptor encephalitis (NMDAR encephalitis) with working memory commonly affected. This study examined cognitive outcomes in patients treated for NMDAR encephalitis using a neurocognitive test battery and a working memory paradigm, compared with healthy controls & patients with schizophrenia.

METHODS

Adult patients previously treated for NMDAR encephalitis were assessed using the Cambridge Automated Neuropsychological Test Battery (CANTAB) for working memory & episodic memory. Patients completed the N-back task during functional MRI (fMRI) scanning. Results were compared to patients with schizophrenia and healthy controls from a prior study.

RESULTS

Twelve patients were recruited [11 women; mean (SD) age 37(12) years; Mean (SD) duration until immunotherapy treatment 7.09 (2.43) weeks]. Data were compared to 14 patients with schizophrenia [10 women; mean (SD) age 39 (12) years] and 14 healthy controls [7 women; mean (SD) age 30 (6) years]. Significant differences in letter number sequencing, spatial working memory, logical memory I, 1-back, and 2-back performance were observed (Cohen's d = 0.766 to 1.254, p< 0.05), driven by poorer performance by patients with schizophrenia. While patients with NMDAR encephalitis exhibited slightly lower performance compared with healthy controls, none of these differences were statistically significant. No significant differences in neural activation during 1-back or 2-back performance were observed.

CONCLUSIONS

Study findings suggest cognitive performance in patients treated for NMDAR encephalitis approaches normal over time. Prompt treatment with immunotherapy is associated with improved cognitive outcomes. Psychiatric services should be aware of the clinical features of autoimmune encephalitis.

Abnormal Brain MRI in Anti-NMDA Receptor Encephalitis: Clinical and Prognostic Implications

BACKGROUND AND OBJECTIVES

Abnormal brain MRI is associated with poor outcomes in anti-N-methyl-d-aspartate receptor encephalitis (NMDARE). We aimed to characterize the lesions on brain MRI in NMDARE and to assess the clinical and prognostic associations.

METHODS

This retrospective cohort study included patients with NMDARE identified at the French Reference Center for Autoimmune Encephalitis, with at least a one-year follow-up, and with available brain MRI results. In case of brain extralimbic lesion, the image files were reviewed when available. Clinical data were collected from medical records. Multivariable logistic regression analysis was used to study the outcomes at 2-year follow-up; recovery was defined as modified Rankin Scale score ≤1.

RESULTS

Among the 255 patients included, 37 (14.5%) had limbic hyperintensities and 41 (16.1%) had extralimbic lesions that included multiple sclerosis (MS)-like lesions (14/41, 34.1%); extensive lesions (5/41, 12.2%); and poorly demarcated fluffy lesions, either multifocal (10/41, 24.4%) or involving the cerebral cortex or cerebellum (6/41 each, 14.6%). Extralimbic lesions coexisting with limbic lesions (19/41 patients, 46.3%) were mostly fluffy lesions (11/19, 57.9%). Ten patients had overlapping demyelinating syndromes: 4 with MS, 4 with myelin oligodendrocyte glycoprotein-associated disorder, and 2 with neuromyelitis optica spectrum disorder; all had MS-like (7/10 patients) or extensive (3/10 patients) lesions, and none had fluffy lesions. Extralimbic lesions were associated with symptoms nontypical for NMDARE (23/41, 56.1%, p < 0.001), especially cerebellar ataxia (17/41, 41.5%) and motor impairment (12/41, 29.3%). At 2 years, patients with MS-like or extensive lesions had a lower recovery rate (5/12, 41.7%, and 1/4, 25%, respectively) compared with the patients without extralimbic lesions (124/162, 76.5%; p = 0.014 and p = 0.047, respectively). In multivariable analysis, MS-like lesions, but not hippocampal nor fluffy lesions, were associated with absence of recovery at 2 years (adjusted OR 0.1, 95% CI 0.03-0.42, p = 0.002; extensive lesions [n = 4] not included in the analysis).

DISCUSSION

Brain MRI lesions in NMDARE include limbic hyperintensities and 3 patterns of extralimbic lesions, which are associated with nontypical NMDARE symptoms. Moreover, MS-like and extensive lesions, but not fluffy nor hippocampal lesions, are associated with overlapping demyelinating syndromes and poor clinical outcomes at 2 years. These findings can have practical implications on the monitoring of patients with NMDARE.

Peripheral T-cell subset activation in NMDAR encephalitis: Insights into pathogenesis and biomarker potential for disease monitoring

BACKGROUND

N-methyl-d-aspartate receptor encephalitis (NMDAR-E) is a severe autoimmune disorder characterized by neuropsychiatric symptoms and immune dysregulation ，involves T-cell dysregulation, but specific T-cell subset roles remain unclear. This study analyzed peripheral blood T-cell subsets as biomarkers for monitoring and severity prediction.

METHODS

Peripheral blood samples from 32 NMDAR-E patients, 31 antibody-mediated encephalitis, 26 viral encephalitis patients, and 23 healthy controls were analyzed using flow cytometry. Key markers of T-cell activation and co-stimulation were assessed. Clinical outcomes were correlated with immune profiles to develop a predictive model.

RESULTS

NMDAR-E patients showed elevated CD4+ T-cell activation, with increased CD28, CD38, and HLA-DR expression versus controls, indicating immune hyperactivation with compensatory regulation. The T-cell-based model predicted severe cases with high accuracy (AUC = 0.91).

CONCLUSION

CD4+ T-cell activation is central to NMDAR-E pathogenesis, highlighting diagnostic/therapeutic potential. Future studies must validate the model in larger cohorts and address peripheral blood analysis limitations.

The Clinical Trial Landscape in Autoimmune Encephalitis: Challenges and Opportunities

Autoimmune encephalitis (AE) is an important cause of neurologic morbidity and mortality. Treatment algorithms are primarily based on observational studies, retrospective series, and expert opinion. Despite clinical improvement with empiric therapy, recovery is often incomplete with a substantial burden of residual neurologic deficits and recurring symptoms. There is a pressing need for higher quality evidence-based therapies. However, designing and conducting clinical trials for patients with rare diseases such as AE has specific challenges, including slow recruitment, suboptimal outcome measures, and inclusivity vs exclusivity of the various disease subtypes. The anticipated knowledge gained from AE clinical trials emphasizes the need to overcome these challenges and support the development of the next generation of clinical trials. Yet, given these challenges, alternative approaches may be required. In this article, we review past and present clinical trials in AE with a focus on studies enrolling patients with neural surface antibodies. We discuss the potential challenges and opportunities inherent to clinical trials in rare diseases and provide an outlook for the field.

Neuroimmunology and Sleep

The immune system and sleep are inextricably linked in both health and pathological conditions. Tightly regulated neuroimmune processes are critical for the physiological maintenance of healthy sleep. Reciprocally, sleep disturbances can detrimentally affect immune homeostasis and predispose to increased risk of autoimmune conditions, which themselves are bidirectionally associated with a higher risk of sleep disturbances. Autoimmune diseases of the central nervous system (CNS), particularly conditions that affect neuroanatomical regions involved in sleep homeostasis and nocturnal respiration, are associated with an increased risk sleep disorders that may impact diagnosis, clinical course, and management. This review summarizes the bidirectional relationship between sleep and immunity and highlights several exemplar autoimmune conditions of the CNS that include sleep disorders as a consequence or diagnostic feature of the disorder.

Detection of antibodies in suspected autoimmune encephalitis diseases using machine learning

In our study, we aim to predict the antibody serostatus of patients with suspected autoimmune encephalitis (AE) using machine learning based on pre-contrast T2-weighted MR images acquired at symptom onset. A confirmation of seropositivity is of great importance for a reliable diagnosis in suspected AE cases. The cohort used in our study comprises 98 patients diagnosed with AE. 57 of these patients had previously tested positive for autoantibodies associated with AE. In contrast, no antibodies were detected in the remaining 41 patients. A manual bilateral segmentation of the hippocampus was performed using the open-source software 3D Slicer on T2-weighted MR-images. Subsequently, 107 Radiomics features were extracted from each T2-weighted MR image utilizing the open source PyRadiomics software package. Our study cohort was randomly divided into training and independent test data. Five conventional machine learning algorithms and a neural network were tested regarding their ability to differentiate between seropositive and seronegative patients. All performance values were determined based on independent test data. Our final model includes six features and is based on a Lasso regression. Using independent test data, this model yields a mean AUC of 0.950, a mean accuracy of 0.892, a mean sensitivity of 0.892 and a mean specificity of 0.891 in predicting antibody serostatus in patients with suspected AE. Our results show that Radiomics-based machine learning is a very promising method for predicting serostatus of suspected AE patients and can thus help to confirm the diagnosis. In the future, such methods could facilitate and accelerate the diagnosis of AE even before the results of specific laboratory tests are available, allowing patients to benefit more quickly from a reliable treatment strategy.

A novel simple immunoassay for quantification of blood anti-NMDAR1 autoantibodies

Low titers of blood circulating anti-NMDAR1 autoantibodies have been reported in a significant subset of the general human population. Currently, immunohistochemical staining and cell-based assays are the standard methods for their detection and semi-quantification. However, detection and quantification of these low titers of blood circulating anti-NMDAR1 autoantibodies are problematic because of high non-specific background. Development of a new method to more accurately quantify these low titers of blood anti-NMDAR1 autoantibodies will facilitate studies on their potential impacts on psychiatric symptoms and cognition. We previously reported a robust production of anti-NMDAR1 autoantibodies against the ligand binding domain of NMDAR1. As a proof of principle, we report the development of a novel simple immunoassay for quantification of cross-species blood anti-NMDAR1 autoantibodies and its validation with immunohistochemistry and cell-based assays in both humans and mice. Specificity of our quantification was also investigated.

Intrathecal treatment of Anti-N-Methyl-D-Aspartate receptor encephalitis: a promising approach for refractory cases

BACKGROUND

Anti-N-methyl-D-aspartate receptor encephalitis is a severe neurological disorder. While standard treatments work for many patients, up to 25% are resistant to these treatments. In such challenging cases, there is growing interest in using intrathecal approaches.

METHODS

A narrative review of relevant papers was conducted.

RESULTS

Case reports and case series have demonstrated the successful use of intrathecal methotrexate, either alone or in combination with steroids, particularly in pediatric patients. Additionally, intrathecal rituximab has shown promise in select cases.

CONCLUSIONS

Although outcomes vary, this approach appears to be safe and has the potential to rescue refractory cases.

Bridging the gap: insights into sensorimotor deficits in NMDA receptor antibody encephalitis

N-methyl-d-aspartate (NMDA) receptor-mediated autoimmune encephalitis (NMDAR-AE) is the most common cause of autoimmune encephalitis, especially in children and young adults. The disorder is caused by antibodies directed against the GluN1 protein, an obligatory constituent of NMDA receptors, which are key signaling molecules in brain development, learning and memory, and executive function. The manuscript by Zhou et al. offers key insights into aberrant development of cortical pathways that may underly persistent sensorimotor deficits associated with this encephalitis in a newly generated mouse model. This study convincingly links transient exposure to a patient-derived anti-GluN1 mAb during a critical developmental period to lasting disruptions in interhemispheric connectivity through callosal projections. These findings provide insight into the impact of a prevalent autoimmune disorder on fundamental aspects of brain development and establish a model system that could be further employed to probe other aspects of NMDAR-AE pathogenesis.

Caloric requirement targets for nutritional support in adult autoimmune encephalitis: a retrospective cohort study

BACKGROUND

Autoimmune encephalitis (AE) is a severe neurological disease often accompanied by consciousness disturbances, severe swallowing difficulties, and gastrointestinal dysfunction, increasing the risk of malnutrition. However, the optimal caloric intake target during the acute phase of AE remains unclear.

OBJECTIVE

This study aims to evaluate the impact of caloric intake on short-term clinical outcomes in AE patients, specifically focusing on the improvement in Clinical Assessment Scale for Autoimmune Encephalitis (CASE) scores, to provide recommendations for nutritional support during the acute phase.

METHODS

A retrospective study analyzed clinical data from 128 adult AE patients requiring nutritional support, admitted to West China Hospital, Sichuan University, from January 2020 to January 2024. Patients were categorized into low-calorie intake (below 70% of requirements), standard-calorie intake (70-100% of requirements), and high-calorie intake (above 100% of requirements) groups. Multivariate linear and logistic regression models were used to quantify the associations.

RESULTS

Higher caloric intake was significantly associated with improved CASE scores (β = 8.58, SE = 3.75, 95% CI = 1.14 to 16.03, p = 0.02). Low caloric intake negatively impacted the improvement of CASE scores (p = 0.049), particularly in seizures and speech problems. The low-calorie intake group had significantly longer hospital stays and nutrition therapy durations (45.79 ± 30.98 days, p < 0.01; 40.39 ± 31.92 days, p = 0.02).

CONCLUSIONS

Adequate caloric intake has a significant positive impact on the short-term clinical outcomes of AE patients, suggesting that meeting or exceeding caloric requirements may promote neurological recovery in AE patients. Future prospective studies are needed to validate these findings and further optimize nutritional support strategies.

Time moving 100-fold slower: time distortion as a diagnostic clue in anti-NMDA receptor encephalitis

BACKGROUND

The primary symptoms in the early stages of anti-NMDA receptor encephalitis are psychiatric manifestations, making it difficult to distinguish from psychiatric disorders. While anti-NMDA receptor encephalitis requires a completely different treatment approach, the specific psychiatric features of the condition remain poorly identified. Although previous studies have suggested that altered perceptions may be characteristic, few case reports focus on altered perceptions of time or time distortion, a phenomenon closely linked to NMDA receptor dysfunction as seen in individuals using NMDA receptor inhibitors like ketamine and phencyclidine. In this report, we describe two cases of anti-NMDA receptor encephalitis manifesting pronounced time distortion in its early stages, which may serve as diagnostic clues for the early diagnosis and treatment of this potentially lethal condition.

CASE PRESENTATIONS

Two cases of Anti-NMDA receptor encephalitis, both marked by significant time distortion in the early stages and showing near-complete recovery with immunotherapy, are presented in detail. In both cases, time distortion was the predominant symptom among the psychiatric manifestations. Case 1: A middle-aged man experienced a pronounced perception of time moving 100 times slower in the early stages, accompanied by feelings of detachment and auditory abnormalities. This time distortion persisted for over a year, even after other symptoms had fully resolved. Case 2: A young woman reported that time seemed to move two to three times slower in the early stages. Although she did not initially mention time distortion, she confirmed it when specifically questioned.

CONCLUSIONS

Our report suggests that time distortion, particularly the perception of time moving slowly, can be a distinguishing feature in the early stages of anti-NMDA receptor encephalitis. This unique characteristic, especially when occurring independently of other symptoms, is rare as a primary and isolated symptom in other conditions, making it useful for differentiation from time distortion in other psychiatric disorders. Additionally, since some patients may not spontaneously report time distortion, actively assessing this symptom during early evaluation could help improve diagnostic accuracy.

Seronegative autoimmune encephalitis associated with ovarian teratoma and uterine STUMP tumour

This case report details a case of probable seronegative autoimmune encephalitis (AE) secondary to either an ovarian teratoma or a uterine smooth muscle tumour of uncertain malignant potential (STUMP). AE is a neurological disorder often associated with specific autoantibodies. However, cases can occur without identifiable antibodies, necessitating a broader diagnostic approach. We present a woman in her 30s who exhibited sudden-onset acute behavioural disturbance and psychiatric symptoms. Initial investigations, including both infective and autoimmune screening, returned negative. Further investigations revealed an adnexal mass and raised ovarian tumour markers. Both an ovarian teratoma and a uterine STUMP were resected. Postoperatively, the patient demonstrated significant clinical improvement, with resolution of neurological symptoms and normalisation of cognitive function.

Anti-metabotropic glutamate receptor 5 coexistent anti-N-methyl-D-aspartate receptor encephalitis: a case report and literature review

Metabotropic glutamate receptor 5 (mGluR5) antibody encephalitis is an infrequent clinical disorder, initially reported in 2011 among two patients presenting with limbic encephalitis and Hodgkin's lymphoma. Mental and behavioral abnormalities are prevalent manifestations, accompanied by cognitive impairment, movement disorders, seizures, and other associated symptoms. In this report, we present the case of a young female patient who presented with abnormal mental behavior, seizures, and disturbances of consciousness. A cell-based assay (CBA) showed positive IgG metabotropic glutamate receptor 5 in both her serum and cerebrospinal fluid (CSF), as well as positive IgG N-methyl-D-aspartate receptor (NMDAR) in both her serum and CSF. She was diagnosed with mGluR5 overlapping NMDAR antibody encephalitis and received high-dose intravenous methylprednisolone pulse therapy and immunoglobulin therapy. Tumor screening suggested the presence of bilateral ovarian teratoma. However, unfortunately the prognosis was extremely poor. Clinical results suggested that patients with mGluR5-Abs mostly have good prognoses, excepting our case.

Anti N-methyl-D-aspartate receptor encephalitis during pregnancy: A case report

Anti-N-methyl-D-aspartate receptor (NMDA-R) encephalitis is an immune-mediated encephalitis that primarily affects young women. Due to the psychiatric and neurological symptoms, the diagnosis can be challenging, especially during pregnancy. During pregnancy, treatments must take into account the fetal and neonatal risk and the risk of premature delivery. We report a case of anti-NMDA encephalitis in a 31-years-old, 30 weeks pregnant women characterized by predominantly psychiatric symptoms, associated with ovarian teratoma. First-line treatments have led to an improvement in symptoms, allowing the pregnancy to be carried to term and a vaginal delivery.

A Case of Anti-N-Methyl-D-Aspartate Receptor (NMDAR) Encephalitis With Video-Documented Psychogenic Nonepileptic Seizures (PNES)-Mimicking Episodes Initially Considered as Somatic Symptom Disorder

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune disorder characterized by psychiatric symptoms, seizures, and dyskinesias. This case report describes a 30-year-old woman who was initially suspected of having a somatic symptom disorder because of the development of seizures mimicking psychogenic non-epileptic seizures (PNES). At presentation, she was able to engage in conversation and follow instructions, but exhibited slight fever, sensory abnormalities, and non-stereotypical seizures. Over the course of two weeks, she fell into a catatonic stupor. Cerebrospinal fluid (CSF) analysis revealed only mild pleocytosis with CSF-restricted oligoclonal bands. Electroencephalogram, which was unremarkable at presentation, subsequently showed an extreme delta brush pattern. NMDAR antibodies were detected in CSF with two independent assays, confirming the diagnosis of anti-NMDAR encephalitis. First-line immunotherapy with steroids, plasma exchange, and immunoglobulins was ineffective, but second-line immunotherapy with cyclophosphamide led to improvement. This case underscores the importance of considering anti-NMDAR encephalitis in patients with PNES-mimicking episodes, which can be misleading and delay appropriate diagnosis and treatment.

Hippocampal dysfunction after autoimmune encephalitis depending on the antibody type

BACKGROUND

Comprehensive neurocognitive function analyses of autoimmune encephalitis (AE) patients, especially long-term ones, are rare. This study aims to measure cognitive function in patients diagnosed with AE.

METHODS

This case-control study included AE patients (n = 11) with antibodies against NMDA receptor (NMDAR) (n = 4), VGKC (n = 3), GAD (3), and one antibody-negative patient. The control group contained 12 pneumococcal meningo-encephalitis patients (PC). Subgroup analyses compared AE patients with and without NMDAR antibodies. Neurocognitive tests were performed to evaluate verbal and visual memory, face recognition, attentional capacity, incidental learning capacity, and overall cognitive function (Montreal cognitive assessment, MoCA). Limbic structural involvement was assessed through magnetic resonance imaging (MRI). Statistical analyses investigated correlations between antibody status, results of neurocognitive tests, and MRI findings.

RESULTS

Follow-up (AE vs. PC) was 33 (11-95) vs. 96 (26-132) months after diagnosis. Neurocognitive functions were normal in both AE and PC groups in all tests except face recognition, which was pathological in both groups. The overall/recognition/long-delay visual memory (p = 0.009/0.008/0.005) and incidental learning (p = 0.017) scores were significantly higher in NMDAR patients compared to non-NMDAR patients. Non-NMDAR patients with right-sided limbic MRI pathologies had significantly lower overall/recognition/long-delay visual memory (p = 0.006/0.044/0.024) and incidental learning (p = 0.009) scores compared to NMDAR patients.

CONCLUSIONS

We observed mainly normal neurocognitive functions after autoimmune and bacterial encephalitis. However, compared to NMDAR patients, patients with non-NMDAR autoimmune encephalitis showed a significant and material-specific association between a right-sided hippocampal lesion and limitations in figural-mnestic and incidental learning capacities. Neurocognitive functions in AE patients should be further evaluated prospectively and in more detail.

Chaihu Guizhi Decoction prevents cognitive, memory impairments and sensorimotor gating deficit induced by N-methyl-d-aspartate receptor antibody in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Anti-NMDAR encephalitis is one of the most common types of autoimmune encephalitis, primarily presenting with prodromal symptoms, such as fever and headache, followed by a range of neurological and psychiatric symptoms. Chaihu Guizhi Decoction (CGD), a traditional Chinese medicine formulated by Zhang Zhongjing in the Eastern Han Dynasty, has been effectively used in clinical practice to treat the symptoms of Taiyang and Shaoyang disorders, including fever, headache, and psychiatric disorders.

AIM OF THE STUDY

To demonstrate the protective effects of CGD in an animal model of anti-NMDAR encephalitis and explore the potential mechanisms involved.

MATERIALS AND METHODS

UHPLC-HRMS was used to identify CGD's chemical components and serum metabolomic profiles. Network pharmacology and molecular docking were performed to predict potential targets of CGD for the treatment of anti-NMDAR encephalitis. The effect of CGD on anti-NMDAR encephalitis was evaluated using a mouse model induced by patients' antibodies. Behavioral tests were performed to assess cognitive impairment and schizophrenia-like behaviors. The effect of CGD on the cell-surface NMDAR GluN1 subunit in cultured neurons treated with patient antibodies was detected by immunofluorescence. Golgi staining was used to observe morphological changes in hippocampal dendrites. The expression of NMDAR-interacting proteins and various neuroreceptors in the hippocampus were examined to validate the targets predicted using network pharmacology and molecular docking.

RESULTS

CGD alleviated cognitive, memory, and sensorimotor gating deficits in mice treated with anti-NMDAR encephalitis patients' antibodies. Further experiments demonstrated the effect of CGD in preventing NMDAR reduction both in vitro and in vivo. Meanwhile, CGD regulated NMDAR-interacting proteins and dopamine receptors but did not affect hippocampal dendritic morphology and synaptic density. Additionally, CGD modifies metabolic pathways associated with anti-NMDAR encephalitis and other neurological and psychiatric disorders.

CONCLUSIONS

CGD exhibited protective effects against anti-NMDAR encephalitis by mitigating the antibody-induced reduction in NMDAR and NMDAR-interacting proteins.

Efficacy of rituximab as second-line therapy for autoimmune encephalitis: A systematic review and meta-analysis

Background

Approximately 20%-50 % of individuals with autoimmune encephalitis (AE) demonstrate suboptimal responses to first-line therapies, leading to persistent neurological deficits and the need for second-line interventions. Although rituximab has shown potential as an alternative treatment in AE, the existing evidence remains insufficient. This study systematically evaluated and meta-analyzed the efficacy of rituximab in AE patients who either failed or exhibited inadequate responses to first-line treatments, aiming to refine and optimize therapeutic strategies for AE.

Methods

A comprehensive search of PubMed, Embase, and the Cochrane Library databases was conducted, covering studies published up to June 10, 2024. In addition, manual cross-referencing of relevant studies was performed using both subject-specific and free-text terms such as "Rituximab," "Rituxan," "Mabthera," "RTX," "Mab," "Ma," "AE," "encephalitis," "Anti-NMDAR encephalitis," and "autoimmune encephalitis." Data on rituximab's efficacy as a second-line therapy in AE were independently screened and extracted by two researchers. Statistical analyses were conducted using R4.2.1 software to assess the pooled outcomes of the included studies.

Results

Analysis of 14 studies involving 277 AE cases revealed an 80 % favorable prognosis rate (0.72-0.89) for rituximab, with superior efficacy in patients under 18 years compared to those over 18 (I2 = 65.9 %, 38.7%-81.0 %; p < 0.01). The prognosis rate for patients under 18 was 0.85 (0.76-0.93), while for those over 18, it was 0.72 (0.56-0.88). Furthermore, a disease duration of ≤180 days correlated with a better prognosis than durations exceeding 180 days, with rates of 0.82 (0.69-0.94) and 0.74 (0.61-0.87), respectively.

Conclusion

Rituximab demonstrates an 80 % favorable prognosis rate in AE cases unresponsive to first-line treatments, particularly in patients under 18 or those with disease duration ≤180 days.

Clinical features of autonomic dysfunction in children with anti-N-methyl-D aspartic receptor encephalitis

BACKGROUND

Anti-N-methyl-D-aspartic receptor encephalitis (Anti-NMDAR encephalitis) is the most prevalent form of autoimmune encephalitis in pediatric patients. Autonomic dysfunction is a frequent symptom of Anti-NMDAR encephalitis, yet it often goes unnoticed by pediatricians. Studies have indicated that pediatric patients with autonomic dysfunction exhibit a poorer prognosis compared to those without. To date, research on autonomic dysfunction in encephalitis has predominantly focused on adults, with no studies conducted on pediatric populations. This analysis examines the clinical features of pediatric patients with Anti-NMDAR encephalitis complicated by autonomic dysfunction.

METHODS

We performed a retrospective analysis of patients diagnosed with Anti-NMDAR encephalitis at the Department of Neurology, Children's Hospital affiliated to the Capital Institute of Pediatrics, from June 2017 to June 2023. Patients were categorized based on the presence or absence of autonomic dysfunction during their illness. We summarized and compared the clinical features of children with autonomic dysfunction and analyzed the risk factors for its development in pediatric Anti-NMDAR encephalitis patients.

RESULTS

A total of 56 children were included in this study. Twenty-two (39.3%) exhibited autonomic nervous dysfunction. The most prevalent symptom of autonomic dysfunction was cardiovascular autonomic dysfunction(21/22, 95%),with the specific manifestations being sinus tachycardia (8 cases), ventricular premature beats (2 cases), atrioventricular block (2 cases), atrial premature beats (3 cases), and sinus bradycardia (4 cases),hypertension(1 case) and cardiac arrest(1 case). Other symptoms included gland secretion dysfunction (19/22, 86%),ventilate dysfunction(3/22,14%), thermoregulatory dysfunction (3/22,14%), bladder dysfunction(2/22,9%). Compared to the group without autonomic dysfunction, the group with dysfunction showed significantly higher rates of prodrome infection, tumor complications (all ovarian teratoma), consciousness disturbance, elevated cerebrospinal fluid protein, initiation of second-line and long-term immunotherapy, length of hospital stay, and hospitalization costs (P < 0.05).

CONCLUSION

Among pediatric patients with Anti-NMDAR encephalitis, cardiovascular autonomic dysfunction is the most common form of autonomic dysfunction. Those with autonomic dysfunction have a worse prognosis and longer hospital stays. Active initiation of second-line and long-term immunotherapy is recommended.

Immune-related encephalitis after immune checkpoint inhibitor therapy

BACKGROUND

Immune checkpoint inhibitors (ICI) have revolutionized cancer treatment but can trigger immune-related encephalitis. We report one of the largest case series of patients with immune-related encephalitis and review of the literature.

METHODS

Retrospective series of patients with immune-related encephalitis and literature review.

RESULTS

Fourteen patients with cancer treated with ICI (50% combination therapy) developed immune-related encephalitis. Diagnostic testing revealed cerebral spinal fluid (CSF) lymphocytic pleocytosis (85%) and elevated protein (69%), abnormal brain magnetic resonance imaging(MRI) (33%) or brain FDG-PET (25%), electroencephalogram (EEG) abnormalities (30%), and autoantibodies (31%). Encephalitis treatment included: corticosteroids (86%), intravenous immunoglobulin (IVIg) (36%), plasmapheresis (7%), and rituximab (29%). There were no deaths and 12 patients had significant recovery, although long-term complications were observed. All patients discontinued ICI. Longitudinal follow-up demonstrated anti-cancer response to ICI at 3 months (85%) and 6 months post-ICI initiation (77%). A literature review identified 132 patients with immune-related encephalitis. Most were treated with PD-1 inhibitors (18% combination). Common abnormalities included elevated CSF protein (84%) or pleocytosis (77%), abnormal brain MRI (65%), or autoantibodies (47%). Nearly all were treated with corticosteroids, many required additional therapy with IVIg (26%) or rituximab (12%). Most patients had clinical improvement (81%) but a minority (10%) had a clinical relapse after completing corticosteroid taper. ICIs were resumed in 7 patients (5%), with relapse in 3.

CONCLUSIONS AND RELEVANCE

Immune-related encephalitis is treatable and improves with corticosteroids in most cases but may require additional immunosuppression. Re-emergence of encephalitis is rare and does not typically result in adverse outcomes, and this should be considered in neurological immune-related adverse event management guidelines.

Antibodies against neuronal surface antigens in acute stroke: a systematic review and meta-analysis

Background

Antibodies against neuronal surface antigens (NSA-Abs), particularly against the NMDA receptor (NMDAR-Ab), have been reported in acute stroke patients (ASP). However, their role in stroke is far from being understood.

Methods

We conducted a systematic review and meta-analysis to investigate: 1) the frequency of NSA-Abs in patients with acute stroke compared to controls; 2) the de novo appearance of NSA-Abs after stroke; and 3) their effects on the clinical outcome.

Results

We included nine studies in the qualitative analysis and seven in the quantitative analysis. Analyses were restricted to NMDAR-Abs due to the lack of data about other NSA-Abs. Considering only studies that adopted a cell-based assay, IgA-IgM NMDAR-Abs isotypes (but not the IgG) were found more frequently in patients with acute stroke (OR 2.69, 95% CI 2.00-3.62, I2 = 4%). There was no de novo NMDAR-Abs formation after stroke. There was no statistical difference in mean discharge/day-7 NIHSS (SMD 0.21, 95% CI -1.10-1.52, I2 = 84%) and 3-12-month mRS (SMD 0.38, 95% CI -0.56-1.32, I2 = 78%) between patients with stroke with and without NMDAR-Abs seropositivity.

Conclusions

Serum IgA/IgM NMDAR-Abs are more frequent in patients with stroke than controls. Due to several methodological issues, these findings should be interpreted cautiously. Additional, methodologically robust studies are needed to clarify the prevalence and significance of NMDAR-Abs in patients with stroke.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022241278#:~:text=https%3A//www.crd.york.ac.uk/prospero/display_record.php%3FID%3DCRD42022241278, identifier CRD42022241278.

Clinical features and factors associated with outcomes of antibody-negative autoimmune encephalitis in patients requiring intensive care

BACKGROUND AND OBJECTIVES

Antibody-negative autoimmune encephalitis (AE) is a form of encephalitis characterized by the absence of detectable autoimmune antibodies, despite immunological evidence. However, data on management of patients with antibody-negative AE in the intensive care unit (ICU) are limited. This study aimed to explore the characteristics and subtypes of antibody-negative AE, assess the effects of immunotherapy, and identify factors independently associated with poor functional outcomes in patients requiring intensive care.

METHODS

This retrospective, single-center study analyzed consecutive adult patients diagnosed with antibody-negative AE and admitted to the ICU of a large tertiary hospital between 2019 and 2023. Multivariate regression analysis was used to identify factors linked to poor functional outcomes six months after ICU admission, as defined by a modified Rankin Scale score of 3-6. Generalized linear mixed models were applied to evaluate the effect of immunotherapy on longitudinal changes in the Clinical Assessment Scale in Autoimmune Encephalitis and modified Rankin Scale scores.

RESULTS

Of the 1220 patients with severe encephalitis admitted to the ICU, 107 were diagnosed with antibody-negative AE and included in the analysis. Six months after ICU admission, 67 patients (62.6%) had poor functional outcomes, including 28 deaths (26.2%). Factors independently associated with poor outcomes were high-dose corticosteroid therapy (odds ratio [OR] 8.734, 95% confidence interval [CI] 2.483-30.717), older age at onset (OR 1.063, 95% CI 1.028-1.099), acute respiratory failure at ICU admission (OR 10.931, 95% CI 2.062-57.751), and dyskinesia/dystonia (OR 14.109, 95% CI 1.336-148.957). The generalized linear mixed model also indicated that high-dose corticosteroid therapy was associated with poorer longitudinal outcomes.

CONCLUSIONS

While high-dose corticosteroids are frequently used to treat AE, their risks may outweigh their benefits in severe antibody-negative AE cases. Older patients and those with dyskinesia/dystonia or respiratory failure, may require more careful monitoring and timely intervention for improved outcomes. However, prospective validation of these findings is necessary to confirm their applicability and guide future treatment strategies.

Interpretable machine learning model for predicting the prognosis of antibody positive autoimmune encephalitis patients

OBJECTIVE

The objective was to utilize nine machine learning (ML) methods to predict the prognosis of antibody positive autoimmune encephalitis (AE) patients.

METHODS

The encephalitis data from the Global Burden of Disease (GBD) study is analyzed to reflect the disease burden of encephalitis. This study included 187 patients with AE. 121 patients as training set and 67 patients as validation set. Decision trees (DT), random forest (RF), extreme gradient boosting (XGBoost), k-nearest neighbor (KNN), support vector machine (SVM), naive bayes (NB), neural network (NN), light gradient boosting machine (LGBM), and logistic regression (LR) are ML methods used to construct predictive models. The constructed models were validated for discrimination, calibration and clinical applicability using validation set data. Shapley additive explanation (SHAP) analysis was used to explain the model.

RESULTS

The number of encephalitis worldwide deaths, incidence and prevalence is increasing every year from 2010 to 2021. The training set included 121 patients with AE. Univariate analysis and LASSO screening identified six variables. The results of constructing models using 9 ML methods showed RF had the highest accuracy (0.860), followed by XGBoost (0.826), with F1 scores of 0.844 and 0.807, respectively. Validation set data showed good discrimination, calibration and clinical applicability of the model. The SHAP values of infection, CSF monocyte percentage, and prealbumin were 0.906, 0.790, and 0.644, respectively.

LIMITATIONS

As a rare disease, the sample size of this study is relatively small.

CONCLUSION

The model constructed using RF and XGBoost has good performance, good discrimination, calibration, clinical applicability, and interpretability.

Anaesthetic management of laparotomy in a patient with anti-NMDA receptor antibody-mediated encephalitis

Management of cases of anti-N-methyl-D-aspartate (NMDA) antibody-mediated encephalitis is very challenging to anaesthesiologists as this receptor is the target of many anaesthetics. We report a woman diagnosed with anti-NMDA antibody-mediated encephalitis posted for laparotomy. She presented with generalised tonic-clonic seizures. Testing revealed anti-NMDA antibodies and anti-SOX antibodies. Ultrasonography of the abdomen showed a right adnexal cystic lesion; hence, the patient was taken up for right ovarian cystectomy after obtaining high-risk consent. A combination of total intravenous anaesthesia with endotracheal intubation under bispectral index monitoring and bilateral transversus abdominis plane block for postoperative analgesia was administered. Postoperatively, there was no excessive drowsiness or hypoventilation. Prioritising careful monitoring and tailored anaesthesia techniques to minimise the risk of triggering neurological exacerbations while ensuring optimum surgical conditions are met is of paramount importance. Meticulous planning and careful use of resources enabled the administration of safe anaesthesia.

Anti-NMDA Receptor Encephalitis, Human Papillomavirus, and microRNA

BACKGROUND

Anti-N-methyl-d-aspartate (Anti-NMDA) receptor encephalitis is a rare autoimmune disease, which is caused by antibodies attacking NMDA receptors in the brain. Previous studies revealed that this disorder might be induced by vaccination. Vaccination is the most useful strategy to prevent human or animal infectious diseases. Although vaccines can produce immunity against diseases, at low risk, they may trigger serious adverse events. Anti-NMDA receptor encephalitis has been studied to be related to the H1N1 (influenza A virus subtype H1N1), tetanus/diphtheria/pertussis and polio vaccine, Japanese encephalitis, yellow fever, and coronavirus disease 2019 (COVID-19) vaccination. Several cases have been reported that anti-NMDA receptor encephalitis could also be triggered by the human papillomavirus (HPV) vaccine. However, there is a lack of studies to investigate the underlying mechanism.

METHODS

In this paper, the association between anti-NMDA receptor encephalitis and HPV vaccination is discussed in terms of their microRNA (miRNA) biomarkers. Phylogenetic tree and distance similarity analyses are used to explore the relationship between their miRNA biomarkers.

RESULTS

The results show a higher degree of similarity between miRNA biomarkers associated with HPV and anti-NMDA receptor encephalitis or related vaccines when compared to the overall miRNAs. It indicates that while the risk of HPV triggering anti-NMDA receptor encephalitis is low, a connection between anti-NMDA receptor encephalitis and HPV vaccination cannot be ruled out.

CONCLUSION

This finding suggests that in cases where individuals receiving HPV vaccination experience psychiatric or neurological symptoms, it should be considered to diagnose anti-NMDA receptor encephalitis, given the exclusion of other possible complications.

Lipids shape brain function through ion channel and receptor modulations: physiological mechanisms and clinical perspectives

Lipids represent the most abundant molecular type in the brain, with a fat content of ∼60% of the dry brain weight in humans. Despite this fact, little attention has been paid to circumscribe the dynamic role of lipids in brain function and disease. Membrane lipids such as cholesterol, phosphoinositide, sphingolipids, arachidonic acid, and endocannabinoids finely regulate both synaptic receptors and ion channels that ensure critical neural functions. After a brief introduction on brain lipids and their respective properties, we review here their role in regulating synaptic function and ion channel activity, action potential propagation, neuronal development, and functional plasticity and their contribution in the development of neurological and neuropsychiatric diseases. We also provide possible directions for future research on lipid function in brain plasticity and diseases.

Neuroglia in autoimmune encephalitis

Neuroglial cells play a crucial role in central nervous system (CNS) health and disease. Antibody-associated autoimmune encephalitis (AE) represents a group of inflammatory brain diseases with antibodies (Abs) against neuronal cell surface (e.g., anti-N-methyl-d-aspartate receptor (NMDAR), anti-leucine-rich glioma-inactivated 1 (LGI1), γ-aminobutyric acid (GABA) type A or B receptor (GABAA/BR)) or intracellular neuronal proteins. AE with Abs against glial antigens, e.g., myelin oligodendrocyte glycoprotein (MOG), glial fibrillary acidic protein (GFAP) are also described. Besides the known pathomechanisms with direct pathogenic effects of primary neuronal Abs and activation of innate (dendritic cells) and adaptive (B and T cells) immune systems, research findings suggest the involvement of glial cells including astrocytes, microglia, oligodendrocytes in the pathogenesis of Ab-associated AE, but only a limited number of studies is available. Neuropathologic findings showed reactive astrogliosis and microgliosis with microglial activation/proliferation, e.g., in anti-NMDAR and anti-LGI1 encephalitis. Direct effects of the GABAAR and NMDAR Abs on astrocytic receptors are discussed. Because of the primary involvement of B and T cells in the pathogenesis of Ab-associated AE it can be assumed that astrocytic and microglial activation is largely a response to the primary changes, but additional direct effects of Abs on astrocytic receptors are possible. Further research in this field is required to explore the exact role of glial cells in Ab-associated AE.

Current and Future Roles of Chimeric Antigen Receptor T-Cell Therapy in Neurology: A Review

Importance

Advancements in molecular engineering have facilitated the creation of engineered T cells that express synthetic receptors, termed chimeric antigen receptors (CARs). This is promising not only in cancer treatment but also in addressing a spectrum of other conditions. This review provides a comprehensive overview of the current approaches and future potential of CAR T-cell therapy in the field of neurology, particularly for primary brain tumors and autoimmune neurological disorders.

Observations

CAR T-cell therapy for glioblastoma is promising; however, first-in-human trials did not yield significant success or showed only limited success in a subset of patients. To date, the efficacy of CAR T-cell therapies has been demonstrated in animal models of multiple sclerosis, but larger human studies to corroborate the efficacy remain pending. CAR T cells showed efficacy in treatment of patients with relapsed or refractory aquaporin 4-immunoglobulin G-seropositive neuromyelitis optica spectrum disorders. Further studies with larger patient populations are needed to confirm these results. Success was reported also for treatment of cases with generalized myasthenia gravis using CAR T cells. Chimeric autoantibody receptor T cells, representing a modified form of CAR T cells directed against autoreactive B cells secreting autoantibodies, were used to selectively target autoreactive anti-N-methyl-d-aspartate B cells under in vitro and in vivo conditions, providing the basis for human studies and application to other types of autoimmune encephalitis associated with neuronal or glial antibodies.

Conclusions and Relevance

CAR T cells herald a new era in the therapeutic landscape of neurological disorders. While their application in solid tumors, such as glioblastoma, has not universally yielded robust success, emerging innovative strategies show promise, and there is optimism for their effectiveness in certain autoimmune neurological disorders.

Seizures in a healthy 20-year-old woman

ABSTRACT

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is the most common type of autoimmune encephalitis. The initial presentation can vary from subtle mental status changes to more severe symptoms such as seizures, coma, or death. This case report outlines the interdisciplinary and collaborative approach to diagnosing and treating a patient with anti-NMDAR autoimmune encephalitis.

Metabolic Characterization of Cerebrospinal Fluid for Patients With Autoimmune Encephalitis: A Preliminary Study

BACKGROUND

Metabolomics offers promise in uncovering potential biomarkers and understanding the pathophysiology of autoimmune encephalitis (AE), which is a cluster of disorders with the host immune system targeting self-antigens expressed in the central nervous system (CNS). In this research, our objective was to explore metabolic characterization in cerebrospinal fluid (CSF) from individuals with AE, aiming to shed light on the pathophysiology of AE.

METHODS

A targeted approach was applied using an ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) system to study CSF metabolites in patients with AE (n = 18), and control subjects without neurological diseases (n = 17).

RESULTS

A total of 21 potential biomarkers were acquired by getting the intersection of the differential metabolites from univariate statistics and multidimensional statistics between the AE (cell-based assay panel, CBA-panel) group and the control group. Specifically, the levels of pyruvic acid and oxoglutaric acid were notably elevated in the AE(CBA-panel) group compared to those in the control group, indicating that the dysregulated TCA cycle may play a pivotal role in the progression of AE(CBA-panel). Interestingly, 27 potential biomarkers were acquired by getting the intersection of the differential metabolites from univariate statistics and multidimensional statistics between the anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) group and the control group, suggesting that the disparities between patients with greater homogeneity and the controls are amplified. In addition, seven differential metabolites were identified by the univariate statistics between the AE (tissue-based assay, TBA) group and the control group, including alpha-linolenic acid and gamma-linolenic acid, suggesting that dysregulated biosynthesis of unsaturated fatty acids and alpha-linolenic acid metabolism might be crucial in the AE(TBA) disease course.

CONCLUSION

Collectively, distinct metabolic profiles were evident in the CSF of the AE group compared to the control group, notably involving metabolites associated with mitochondrial dysfunction, which helped to elucidate the pathophysiology of AE.

Disrupted callosal connectivity underlies long-lasting sensory-motor deficits in an NMDA receptor antibody encephalitis mouse model

N-methyl-d-aspartate (NMDA) receptor-mediated autoimmune encephalitis (NMDAR-AE) frequently results in persistent sensory-motor deficits, especially in children, yet the underlying mechanisms remain unclear. This study investigated the long-term effects of exposure to a patient-derived GluN1-specific mAb during a critical developmental period (from postnatal day 3 to day 12) in mice. We observed long-lasting sensory-motor deficits characteristic of NMDAR-AE, along with permanent changes in callosal axons within the primary somatosensory cortex (S1) in adulthood, including increased terminal branch complexity. This complexity was associated with paroxysmal recruitment of neurons in S1 in response to callosal stimulation. Particularly during complex motor tasks, mAb3-treated mice exhibited significantly reduced interhemispheric functional connectivity between S1 regions, consistent with pronounced sensory-motor behavioral deficits. These findings suggest that transient exposure to anti-GluN1 mAb during a critical developmental window may lead to irreversible morphological and functional changes in callosal axons, which could significantly impair sensory-motor integration and contribute to long-lasting sensory-motor deficits. Our study establishes a new model of NMDAR-AE and identifies novel cellular and network-level mechanisms underlying persistent sensory-motor deficits in this context. These insights lay the foundation for future research into molecular mechanisms and the development of targeted therapeutic interventions.

Therapeutic potential of D-amino acid oxidase inhibitors for cognitive impairment associated with schizophrenia: learnings from luvadaxistat

Hypofunction of the N-methyl-D-aspartate receptor (NMDAR) has been proposed to underlie the pathophysiology of schizophrenia, suggesting that promoting NMDAR activity may alleviate the negative or cognitive symptoms associated with schizophrenia. To circumvent excitotoxicity that may accompany direct agonism of the glutamate binding site on the NMDAR, therapeutic trials have focused on targeting the glycine binding site on the NMDAR. Direct administration of either glycine or D-serine, both of which are endogenous coagonists at the NMDAR glycine site, has yielded mixed outcomes across an array of clinical trials investigating different doses or patient populations. Furthermore, directly administering D-serine and glycine is challenging, and thus attention has turned to alternative, indirect methods that increase endogenous D-serine and glycine levels in the brain, such as D-amino acid oxidase (DAAO) inhibitors and glycine transporter 1 inhibitors, respectively. In this review, we provide an overview of the evidence supporting the potential of NMDAR modulators in general, and DAAO inhibitors in particular, as potential adjunctive treatments for schizophrenia. We also discuss the preclinical and clinical data related to luvadaxistat, an investigational highly selective and potent DAAO inhibitor that was under development for the treatment of the cognitive impairment associated with schizophrenia.

Long-Term Cognitive, Functional, and Patient-Reported Outcomes in Patients With Anti-NMDAR Encephalitis

BACKGROUND AND OBJECTIVES

Anti-NMDA receptor (anti-NMDAR) encephalitis generally manifests in young adults. Although 80%-90% returns to independence, the majority experience persistent cognitive and psychosocial difficulties. Studies have demonstrated that cognitive recovery may continue for years; the temporal trajectory is largely unknown, as are factors influencing cognitive/psychosocial recovery. Objectives were to (1) describe the cognitive recovery trajectory, (2) assess self-reported outcomes, (3) identify factors relating to outcome, and (4) explore the relation between cognitive and self-reported outcomes, and participation.

METHODS

We performed a large-scale cross-sectional and prospective cohort study. We addressed our nationwide cohort, provided they were (1) older than 16 years, (2) independent preillness, and (3) able to perform cognitive tests and/or self-report. Patients completed Patient-Reported Outcome Measures and neuropsychological assessments (memory, language, perception and construction, and attention and executive functions), and functional outcomes were established (modified Rankin Scale [mRS] score and return-to-work/-education). Outcomes were compared with references and between groups based on clinical characteristics and functional outcomes (T-tests for normalized data and nonparametric tests for patient-reported data). Recovery was visualized by plotting outcomes against time-of-assessment.

RESULTS

We included 92 patients (age 29 ± 2 years; 77% female). Cognitive scores improved with time-of-assessment, up to 36 months after diagnosis (R = 0.35, p = 0.022), with the most enhanced improvement in the first 6 months. This result could be reproduced in prospective patients (n = 12). Beyond 36 months (n = 44), 34% of patients had a persistent impairment (z-score <-1.5 SD) and 65% scored below-average (<-1 SD) in 1 or more cognitive domains, despite a "favorable" outcome measured by mRS (≤2) in the majority (91%). Most affected were memory (mean -0.67 ± 0.89 SD, p = 0.25) and language (-0.75 ± 1.06 SD, p = 0.23). Self-reported complaints remained in emotional well-being (mean 72 ± 25 SD vs norm 82 ± 33 SD, p < 0.001), social functioning (73 ± 26 SD vs 84 ± 22 SD, p < 0.001), energy levels (57 ± 19 SD vs 69 ± 19 SD, p < 0.001), and quality of life (0.85 ± 0.14 SD vs 0.93 ± 0.11 SD, p < 0.001). Many patients did not resume school/work (30%) or needed adjustments (18%). Resuming school/work related to processing speed (-0.14 ± 0.78 SD vs -0.84 ± 1.05 SD, p = 0.039) and well-being (EuroQol 5 Dimensions 5 Levels median 0.90 vs 0.81, p = 0.016).

DISCUSSION

Recovery from anti-NMDAR encephalitis may continue for 3 years, with risk of persisting cognitive deficits, notably in memory and language, and sequelae in social functioning, energy levels, and well-being. The frequently applied outcome measure mRS does not fully capture outcomes. Almost half of patients struggled resuming school/work, associated with cognitive deficits and well-being.

Anti-NMDAR encephalitis presenting with persistent fever and meningitis and responding well to distinctive individualized first-line treatment: A case report

RATIONALE

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an autoimmune encephalitis characterized by diverse neurological and psychiatric symptoms. It predominantly affects young women, particularly those with ovarian teratomas. However, cases without teratomas are also commonly reported, often exhibiting poorer treatment responses and higher relapse rates. Persistent fever and signs of meningitis are rare in such cases. Diagnosis is confirmed through the detection of anti-NMDAR antibodies.

PATIENT CONCERNS

A 15-year-old female presented with episodic loss of consciousness, fever, nuchal rigidity, limb convulsions, and psychiatric symptoms following a stressful exam period. Initial symptomatic treatments were ineffective.

DIAGNOSIS

The diagnosis of anti-NMDAR encephalitis was confirmed through lumbar puncture, brain imaging, and the detection of anti-NMDAR antibodies in cerebrospinal fluid and serum.

INTERVENTIONS

The patient received tailored first-line therapy, including high-dose methylprednisolone and 3 courses of intravenous immunoglobulin (IVIG).

OUTCOMES

The patient exhibited significant clinical improvement, with a reduction in seizure frequency and eventual complete seizure control. Body temperature normalized, and follow-up showed progressive recovery in cognitive and motor functions.

LESSONS

This case highlights the importance of early diagnosis and individualized treatment in anti-NMDAR encephalitis. Repeated IVIG courses proved effective, underscoring the need for personalized treatment plans in managing this condition. Persistent fever and signs of meningitis were rare and contributed to the diagnostic challenge, highlighting the clinical complexity of this case.

Varied Clinical Features and Outcomes of Autoimmune Encephalitis: A Retrospective Case Series

INTRODUCTION

This study discusses the various clinical profiles, investigatory findings, treatment responses, and prognosticating factors in seven cases of autoimmune encephalitis (AE).

METHODS

The clinical records of seven AE patients admitted to the Neurology Department, SRM Medical College Hospital and Research Centre, Chennai, from July 2022 to December 2023 were retrospectively analyzed.

RESULTS

The patients' ages ranged from 18 to 35, and all experienced seizures. Only two patients exhibited cognitive decline and psychiatric problems. All seven cases were clinically diagnosed as AE: three were positive for anti-N-methyl-D-aspartate receptor (anti-NMDAR) antibodies, while the AE panel was negative in the remaining patients. In all cases, contrast imaging of the brain on MRI appeared normal.

CONCLUSION

Patients with AE need to be diagnosed early because prompt immunosuppressive therapy effectively reduces morbidity and mortality. A detailed history, clinical examinations, and relevant investigations are required. Mild and atypical forms with negative autoimmune antibody panels with relatively good outcomes are increasingly encountered.

Structural and functional mechanisms of anti-NMDAR autoimmune encephalitis

Autoantibodies against neuronal membrane proteins can manifest in autoimmune encephalitis, inducing seizures, cognitive dysfunction and psychosis. Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is the most dominant autoimmune encephalitis; however, insights into how autoantibodies recognize and alter receptor functions remain limited. Here we determined structures of human and rat NMDARs bound to three distinct patient-derived antibodies using single-particle electron cryo-microscopy. These antibodies bind different regions within the amino-terminal domain of the GluN1 subunit. Through electrophysiology, we show that all three autoantibodies acutely and directly reduced NMDAR channel functions in primary neurons. Antibodies show different stoichiometry of binding and antibody-receptor complex formation, which in one antibody, 003-102, also results in reduced synaptic localization of NMDARs. These studies demonstrate mechanisms of diverse epitope recognition and direct channel regulation of anti-NMDAR autoantibodies underlying autoimmune encephalitis.

Short delay to initiate plasma exchange or immunoadsorption as synergistic therapies for patients in the acute phase of anti-NMDAR encephalitis

Background

Combined first-line therapies have been frequently adopted for patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. Plasma exchange (PE) or immunoadsorption (IA) was used as an add-on option following initial immunotherapies, including high-dose steroids and intravenous immunoglobulin (IVIG). However, whether a shorter delay of PE or IA can improve the early recovery prognosis of patients with anti-NMDAR encephalitis remains largely unknown.

Objective

To compare short-term clinical improvement between patients with early and late initiation of PE or IA in anti-NMDAR encephalitis.

Design

A retrospective study was conducted for patients admitted with anti-NMDAR encephalitis between January 2015 and December 2023 (n = 29), including 21 patients who received PE or IA as synergistic therapies.

Methods

The clinical prognosis was compared between the early PE/IA group and the late PE/IA group in the research. Primary outcome included changes in the Clinical Assessment Scale for Autoimmune Encephalitis (∆CASE) at 90 and 120 days after encephalitis onset. Secondary outcomes included changes in the modified Rankin scale (∆mRS) after 90 and 120 days from encephalitis onset, and the length of intensive care unit (ICU) stay for patients with severe anti-NMDAR encephalitis.

Results

The ∆CASE scores after 90 and 120 days from encephalitis onset revealed a significant difference between patients with early and late initiation of PE or IA (p ⩽ 0.05). A significant difference in the ∆mRS was also found between patients with early and late initiation of PE or IA in severe encephalitis (p ⩽ 0.05). No significant difference was found in the length of ICU admission (p = 0.101).

Conclusion

Our findings emphasize the importance of considering PE or IA as early as feasible for patients with anti-NMDAR encephalitis, even when steroids and IVIG are in use.

Catatonia in anti-NMDA receptor encephalitis: a case series and approach to improve outcomes with electroconvulsive therapy

Background

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis has been recognised to present with the syndrome of catatonia. In severe cases dysautonomia is representative of malignant catatonia. The treatment with benzodiazepines (BZDs) and electroconvulsive therapy (ECT) may decrease morbidity and mortality in patients presenting with anti-NMDA receptor encephalitis and catatonia.

Methods

This is a retrospective case series of eight patients with anti-NMDA receptor encephalitis treated with ECT. We use clinical prediction scores (Clinical Assessment Scale for Autoimmune Encephalitis [CASE] and anti-NMDAR Encephalitis One-Year Functional Status scores) to compare expected outcomes and observed outcomes.

Results

CASE scores in our group ranged between 5 and 19, with a mean score of 13.8 (median 15.5). NEOS scores ranged from 2 to 4, with a mean and median of 3. Of the eight patients, six had a favourable modified Rankin Score (0-2) at a follow-up of 8 to 12 months. Patients received an average of 29.9 ECT treatments in total.

Conclusions

Based on clinical prediction scores, this cohort had better than expected functional outcomes. We discuss the use of BZDs and ECT in these cases and propose a treatment algorithm for patients who present with catatonic syndrome in anti-NMDA receptor encephalitis.

Association of ovarian teratoma with anti-N-methyl-D-aspartate receptor encephalitis: a case report and narrative review

BACKGROUND

Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a potentially life-threatening autoimmune disorder which is strongly associated with ovarian teratomas in young female patients. The primary aim is to highlight the importance of considering NMDAR encephalitis in the differential diagnosis of young female patients presenting with acute or subacute neuropsychiatric symptoms, especially when accompanied by ovarian teratomas.

CASE DESCRIPTION

This case report and literature review detail the presentation, diagnosis, and treatment of a 35-year-old G4P3 Indigenous woman who initially presented with neuropsychiatric symptoms and fever, having a history of extensive drug and alcohol use. Misdiagnosed initially, the patient's lack of response to standard treatments led to further investigations, revealing paraneoplastic anti-NMDAR encephalitis secondary to a left ovarian teratoma. The report examines the treatment regimen followed, including prednisolone, intravenous immunoglobulin, rituximab injections, and laparoscopic bilateral salpingo-oophorectomy.

CONCLUSIONS

This case underscores the critical need for increased clinical vigilance for anti-NMDAR encephalitis in patients, particularly young females, presenting with neuropsychiatric symptoms and potential ovarian teratomas. The literature review accompanying the case report provides valuable insights into the presentation, diagnosis, and management of this complex condition. Lastly, this study emphasised the diagnostic challenges inherent in paraneoplastic neuropsychiatric syndromes, advocating for a multidisciplinary approach in similar clinical scenarios.

Immune-mediated neurological syndromes associated with childhood cancers

The association of recognisable neurological conditions with an underlying malignancy is well described. In this review we explore the complex interplay of genetic, environmental and tumour factors which contribute to autoimmunity and paraneoplastic conditions. We review the current understanding of the pathogenesis of well recognised paraneoplastic conditions in children including Opsoclonus myoclonus ataxia syndrome, N-Methyl-D Aspartate receptor encephalitis and limbic encephalitis, and the broad approaches to treatment. Rapid advances in oncological treatment has expanded the arsenal of therapeutic modalities. We explore the broad spectrum of immune therapies in childhood cancer, and the potential neurological complications of these novel therapies, and discuss the fine balance of risk and benefit that these bring.

MRI findings in autoimmune encephalitis

Autoimmune encephalitis encompasses a spectrum of conditions characterized by distinct clinical features and magnetic resonance imaging (MRI) findings. Here, we review the literature on acute MRI changes in the most common autoimmune encephalitis variants. In N-methyl-D-aspartate (NMDA) receptor encephalitis, most patients have a normal MRI in the acute stage. When lesions are present in the acute stage, they are typically subtle and non-specific white matter lesions that do not correspond with the clinical syndrome. In some NMDA receptor encephalitis cases, these T2-hyperintense lesions may be indicative of an NMDA receptor encephalitis overlap syndrome with simultaneous co-existence of multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD) or myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Encephalitis with leucine-rich glioma-inactivated 1 (LGI1)-, contactin-associated protein-like 2 (CASPR2)- or glutamic acid decarboxylase (GAD)- antibodies typically presents as limbic encephalitis (LE) with unilateral or bilateral T2/fluid attenuated inversion recovery (FLAIR) hyperintensities in the medial temporal lobe that can progress to hippocampal atrophy. Gamma aminobutyric acid-B (GABA-B) receptor encephalitis also often shows such medial temporal hyperintensities but may additionally involve cerebellar lesions and atrophy. Gamma aminobutyric acid-A (GABA-A) receptor encephalitis features multifocal, confluent lesions in cortical and subcortical areas, sometimes leading to generalized atrophy. MRI is unremarkable in most patients with immunoglobulin-like cell adhesion molecule 5 (IgLON5)-disease, while individual case reports identified T2/FLAIR hyperintense lesions, diffusion restriction and atrophy in the brainstem, hippocampus and cerebellum. These findings highlight the need for MRI studies in patients with suspected autoimmune encephalitis to capture disease-specific changes and to exclude alternative diagnoses. Ideally, MRI investigations should be performed using dedicated autoimmune encephalitis imaging protocols. Longitudinal MRI studies play an important role to evaluate potential relapses and to manage long-term complications. Advanced MRI techniques and current research into imaging biomarkers will help to enhance the diagnostic accuracy of MRI investigations and individual patient outcome prediction. This will eventually enable better treatment decisions with improved clinical outcomes.

Antibodies in neurological diseases: Established, emerging, explorative

Within a few years, autoantibodies targeting the nervous system resulted in a novel disease classification. For several of them, which we termed 'established', direct pathogenicity has been proven and now guides diagnostic pathways and early immunotherapy. For a rapidly growing number of further anti-neuronal autoantibodies, the role in disease is less clear. Increasing evidence suggests that they could contribute to disease, by playing a modulating role on brain function. We therefore suggest a three-level classification of neurological autoantibodies according to the degree of experimentally proven pathogenicity and strength of clinical association: established, emerging, explorative. This may facilitate focusing on clinical constellations in which autoantibody-mediated mechanisms have not been assumed previously, including autoimmune psychosis and dementia, cognitive impairment in cancer, and neurodegenerative diseases. Based on recent data reviewed here, humoral autoimmunity may represent an additional "super-system" for brain health. The "brain antibody-ome", that is, the composition of thousands of anti-neuronal autoantibodies, may shape neuronal function not only in disease, but even in healthy aging. Towards this novel concept, extensive research will have to elucidate pathogenicity from the atomic to the clinical level, autoantibody by autoantibody. Such profiling can uncover novel biomarkers, enhance our understanding of underlying mechanisms, and identify selective therapies.

Predicting the future of autoimmune encephalitides

The concept that many neurologic and psychiatric disorders of unknown cause are immune-mediated has evolved fast during the past 20 years. The main contribution to the expansion of this field has been the discovery of antibodies that attack neuronal or glial cell-surface proteins or receptors, directly modifying their structure and function. These antibodies facilitate the diagnosis and prompt treatment of patients who often improve with immunotherapy. The identification of this group of diseases, collectively named "autoimmune encephalitides", was preceded by many years of investigations on other autoimmune CNS disorders in which the antibodies are against intracellular proteins, occur more frequently with cancer, and associate with cytotoxic T-cell responses that are less responsive to immunotherapy. Here, we first trace the recent history of the autoimmune encephalitides and address how to assess the clinical value and implement in our practice the rapid pace of autoantibody discovery. In addition, we review recent developments in the post-acute stage of the two main autoimmune encephalitides (NMDAR and LGI1) focusing on symptoms that are frequently overlooked or missed, and therefore undertreated. Because a better understanding of the pathophysiology of these diseases relies on animal models, we examine currently available studies, recognizing the existing needs for better and all-inclusive neuro-immunobiological models. Finally, we assess the status of biomarkers of disease outcome, clinical scales, current treatment strategies, and emerging therapies including CAR T-cell technology. Altogether, this overview is intended to identify gaps of knowledge and provide suggestions for improvement and insights for future research.

Asymmetric Bilateral Medial Temporal Lobe Encephalitis Associated With Anti-N-Methyl-D-Aspartate (NMDA) Receptor Antibodies: A Case Report

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis is a rare autoimmune disorder that typically presents with neuropsychiatric symptoms and medial temporal lobe involvement. We report the case of a 24-year-old female with no significant medical history, who developed severe anxiety, memory deficits, and confusion over a two-week period. Neurological examination revealed cognitive dysfunction, asymmetric limb movements, and psychosis. MRI showed bilateral medial temporal lobe hyperintensities, more pronounced on the left, and CSF analysis confirmed elevated protein levels and positive anti-NMDA receptor antibodies. Treatment with high-dose corticosteroids and intravenous immunoglobulin led to significant improvement within three weeks, with a follow-up MRI showing a reduction in lesion size. This case underscores the importance of early diagnosis, particularly when atypical presentations, such as asymmetric temporal lobe involvement, are observed. Awareness of this condition, especially in young women, is critical for timely intervention and management, given its potential association with ovarian teratomas.

Clinical characteristics and prognosis analysis of acute symptomatic seizures secondary to autoimmune encephalitis

Objective

This study aimed to analyze the clinical characteristics and prognosis of patients with autoimmune encephalitis (PWAE) who experienced seizures during the acute phase.

Methods

Clinical data were collected from 84 patients diagnosed with AE at the General Hospital of Ningxia Medical University between January 2015 and January 2023. Patients were divided into seizure and non-seizure groups. Clinical characteristics of both groups were compared, including differences between anti-NMDAR and anti-LGI1 encephalitis within the seizure group. Due to the limited sample size and to avoid overfitting, we focused on univariate logistic regression analysis to identify individual prognostic factors.

Results

A total of 84 patients were enrolled, with 76.19% (64/84) in the seizure group and 23.81% (20/84) in the non-seizure group. The seizure group had a longer hospital stay (p = 0.013), higher rates of impaired consciousness (p = 0.001), and more frequent intensive care unit (ICU) admission (p = 0.011). They also had higher peripheral blood neutrophil-to-lymphocyte ratio (NLR), leukocyte count, and uric acid levels (p = 0.038, p = 0.006, p = 0.020), and were more likely to show slow-wave rhythms on electroencephalography (EEG) (p = 0.031). At 2-year follow-up, there was no significant difference in prognosis between the seizure and non-seizure groups (p = 0.653), with 35.94% (23/64) of the seizure group having a poor prognosis. Status epilepticus (SE), complications, endotracheal intubation, mRS score at discharge, APE2, and RITE2 scores increased the risk of poor prognosis (OR > 1), while intensive care and albumin reduced the risk (OR < 1).

Conclusion

Seizures are common in the early stages of AE, with faciobrachial dystonic seizures (FBDS) characteristic of anti-LGI1 encephalitis and SE and super-refractory status epilepticus (Sup-RSE) frequently observed in anti-NMDAR encephalitis. Seizure semiology across AE subtypes lacks specificity, and no symptoms clearly distinguish immune-mediated from non-immune causes. While seizures are linked to AE severity, particularly in anti-NMDAR encephalitis, they do not appear to impact overall prognosis. SE, complications, endotracheal intubation, modified Rankin Scale (mRS) score at discharge, Antibody-Prevalence in Epilepsy and Encephalopathy (APE2) score, Response to Immunotherapy in Epilepsy and Encephalopathy (RITE2) score, intensive care, and albumin were identified as significant prognostic factors.