Neuronal Surface Antibody-Medicated Autoimmune Encephalitis (Limbic Encephalitis) in China: A Multiple-Center, Retrospective Study

Clinical features, cerebrospinal fluid changes, and prognosis in Chinese patients with autoimmune encephalitis

INTRODUCTION

Autoimmune encephalitis (AE) is a rare, treatable disease of the central nervous system (CNS) caused by an antibody-related immune response. This study is to investigate the correlation of clinical features, cerebrospinal fluid (CSF) characteristics, and prognosis in patients with AE.

METHODS

A total of 71 patients diagnosed with antibody-positive AE were retrospectively analyzed. The patients were divided into three groups: anti-NMDAR group, anti-LGI1 group, and other types. Clinical data were collected to analyze clinical features and CSF results, and prognosis was determined by modified Rankin Scale (mRS).

RESULTS

There was statistical difference in the incidences of decreased consciousness level (P < 0.001), memory loss (P = 0.017), speech disorders (P = 0.035), and dyskinesia (P = 0.001) in different antibodies groups. Younger age (P = 0.018), elevated CSF chloride content (P = 0.006), and white blood cells > 50/mm3 (P = 0.026) were highly correlated with ICU admission. Anti-LGI1 encephalitis had a relatively small risk for ICU admission (P = 0.034), and a lower risk of poor functional recovery (P = 0.048) and recurrence (P = 0.041). Patients with first-line treatment failure (P = 0.021) had an increased risk of poor functional recovery. Delayed treatment (P = 0.011) would increase the risk of recurrence.

CONCLUSION

There are differences in age, gender, clinical characteristics, and CSF results in different subtypes of AE. First-line therapy failure would have poor functional recovery, and delayed therapy would increase the risk of relapse. Chloride ion content and white blood cell count in cerebrospinal fluid are positively correlated with the patient's exacerbation and admission to ICU. These indicators have certain clinical value for the prognosis of AE patients.

CSF Findings in Chinese Patients with NMDAR, LGI1 and GABABR Antibody-Associated Encephalitis

Purpose

CSF inflammation in subtypes of antibody-defined autoimmune encephalitis (AE) ranges in intensity from moderate to severe. In a retrospective, cross-sectional study, we characterized CSF findings in Chinese patients with anti-N-methyl-D-aspartate receptor encephalitis (NMDAR-E), anti-leucine-rich glioma-inactivated 1 encephalitis (LGI1-E), and anti-gamma aminobutyric acid-B receptor encephalitis (GABABR-E).

Patients and Methods

The AE cases, including 102 NMDAR-E, 68 LGI1-E and 15 GABABR-E, were included. CSF inflammatory parameters consisted primarily of CSF leukocytes, oligoclonal bands (OCBs), and CSF/serum albumin ratios (QAlb). Ten serum cytokines were evaluated in order to classify AE subtypes.

Results

88% of NMDAR-E, 80% of GABABR-E, and 51% of LGI1-E patients had aberrant CSF features. In NMDAR-E, the CSF leukocyte count, CSF protein concentration, and age-adjusted QAlb were significantly higher than in LGI1-E, but did not differ from GABABR-E. Blood-CSF barrier dysfunction was less common in NMDAR-E patients with >40 years old. On admission, inflammatory CSF response was more prevalent in NMDAR-E patients with a higher CASE score. With age <60 years, CSF inflammatory changes were less frequent in LGI1-E patients, but more common in GABABR-E patients. MCP-1, IL-10, IL-1β, and IL-4 were potential classifiers for NMDAR-E, LGI1-E, and GABABR-E, and correlated substantially with CSF leukocyte count and QAlb.

Conclusion

Subtype-specific patterns are formed by the various inflammatory CSF parameters in NMDAR-E, LGI1-E, and GABABR-E, and their correlation with disease severity, age, and disease duration. CSF inflammatory characteristics associated with MCP-1, IL-10, IL-1β, and IL-4 may be potential immunopathogeneses targeting markers for these AE subtypes.

Dynamic Contrast-enhanced MRI Quantification of Altered Vascular Permeability in Autoimmune Encephalitis

Background Blood-brain barrier (BBB) permeability change is a possible pathologic mechanism of autoimmune encephalitis. Purpose To evaluate the change in BBB permeability in patients with autoimmune encephalitis as compared with healthy controls by using dynamic contrast-enhanced (DCE) MRI and to explore its predictive value for treatment response in patients. Materials and Methods This single-center retrospective study included consecutive patients with probable or possible autoimmune encephalitis and healthy controls who underwent DCE MRI between April 2020 and May 2021. Automatic volumetric segmentation was performed on three-dimensional T1-weighted images, and volume transfer constant (Ktrans) values were calculated at encephalitis-associated brain regions. Ktrans values were compared between the patients and controls, with adjustment for age and sex with use of a nonparametric approach. The Wilcoxon rank sum test was performed to compare Ktrans values of the good (improvement in modified Rankin Scale [mRS] score of at least two points or achievement of an mRS score of  ≤2) and poor (improvement in mRS score of less than two points and achievement of an mRS score >2) treatment response groups among the patients. Results Thirty-eight patients with autoimmune encephalitis (median age, 38 years [IQR, 29-59 years]; 20 [53%] female) and 17 controls (median age, 71 years [IQR, 63-77 years]; 12 [71%] female) were included. All brain regions showed higher Ktrans values in patients as compared with controls (P < .001). The median difference in Ktrans between the patients and controls was largest in the right parahippocampal gyrus (25.1 × 10-4 min-1 [95% CI: 17.6, 43.4]). Among patients, the poor treatment response group had higher baseline Ktrans values in both cerebellar cortices (P = .03), the left cerebellar cortex (P = .02), right cerebellar cortex (P = .045), left cerebral cortex (P = .045), and left postcentral gyrus (P = .03) than the good treatment response group. Conclusion DCE MRI demonstrated that BBB permeability was increased in all brain regions in patients with autoimmune encephalitis as compared with controls, and baseline Ktrans values were higher in patients with poor treatment response in the cerebellar cortex, left cerebral cortex, and left postcentral gyrus as compared with the good response group. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Filippi and Rocca in this issue.

Survival Analysis of Immunotherapy Effects on Relapse Rate in Pediatric and Adult Autoimmune Encephalitis

BACKGROUND AND OBJECTIVES

Prior observational studies for autoimmune encephalitis (AE) have mostly focused on outcomes after acute immunotherapies with better outcomes associated with earlier immunotherapy use. However, the impact of long-term immunotherapy and its association with clinical relapse is not well known.

METHODS

We conducted a retrospective study of consecutive patients meeting published clinical criteria for AE evaluated at UC San Diego and Rady Children's Hospital from January 2007 to November 2021. Survival analysis and Cox multivariable regression models were used to evaluate relapse risk using rituximab exposure as a time-dependent variable. Pooled and age-stratified analyses were performed.

RESULTS

A total of 204 pediatric and 380 adult participants were screened of which 30 pediatric and 75 adult participants were included. The most common antibody subtype in both cohorts was anti-NMDA receptor (76% in pediatric, 34% in adult). Relapses occurred in 31% of pediatric antibody-positive, 40% of adult antibody-positive, and 20% of adult antibody-negative cases. Times to first relapse (TTFR) were 10.6 ± 7.4 months (pediatric antibody-positive), 13.1 ± 24.5 months (adult antibody-positive), and 6.9 ± 3.8 months (adult antibody-negative). Rituximab was the most common second-line immunotherapy used. Combining pediatric and adult data, rituximab use was associated with a 71% lower hazard for time to first relapse (hazard ratio [HR] 0.29, 95% CI 0.09-0.85) and 51% lower hazard for recurring relapses (HR 0.49, 95% CI 0.9-1.26). The HR for TTFR with rituximab use in children was 0.30 (95% CI 0.05-1.69), 0.29 (95% CI 0.07-1.29) in adults, 0.32 in non-NMDA antibody-positive encephalitis (95% CI 0.07-1.39), and 0.42 (95% CI 0.07-2.67) for anti-NMDAR.

DISCUSSION

Relapses are common in pediatric and adult patients with AE, although less frequently in anti-NMDARE. Using a rigorous survival model, we demonstrate a substantial benefit of rituximab use for reducing relapse rates in AE, especially for the adult population.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that rituximab is associated with a lower hazard to relapse in patients with AE.

Movement disorders in cell surface antibody mediated autoimmune encephalitis: a meta-analysis

Background

Autoimmune encephalitis (AE) is an increasingly recognized neuroinflammatory disease entity in which early detection and treatment leads to the best clinical outcomes. Movement disorders occur in AE but their characteristics are not well defined.

Objectives

To identify the frequency, classification, and prognostic significance of movement disorders in AE.

Methods

We conducted a systematic review and random-effects meta-analysis of movement disorders in cell surface antibody mediated AE. The frequency of any movement disorder as well as the classification of movement disorders in AE serotypes was determined. We looked at adults 18 years and older and included publications that described at least 10 cases. We used the following four electronic databases: Medline (Ovid), EMBASE (Ovid), APA Psychinfo, and Cochrane library.

Results

A total of 1,192 titles and abstracts were reviewed. Thirty-seven studies were included in the final meta-analysis. At least one kind of movement disorder was present in 40% of the entire AE cohort, 53% with anti-NMDA receptor antibodies, 33% with anti-CASPR2 antibodies, 30% with anti-LGI1 antibodies and 13% with anti-GABA receptor antibodies. Dyskinesia was the commonest movement disorder in anti-NMDA antibody mediated AE and faciobrachial dystonic seizures were most frequent in anti-LGI1 antibody mediated AE. Patients with a movement disorder tended to have a higher mortality. The risk of bias in the included studies was mostly moderate or high.

Conclusion

Movement disorders are common in AE and their identification, in conjunction with other clinical and paraclinical features, may facilitate earlier diagnosis. The prognostic implications of movement disorders in AE warrant further dedicated study.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier: CRD42023386920.

Long-term efficacy and safety of different corticosteroid courses plus mycophenolate mofetil for autoimmune encephalitis with neuronal surface antibodies without tumor

Objective

To compare the efficacy and safety of different-course corticosteroids plus mycophenolate mofetil (MMF) as maintenance therapy in autoimmune encephalitis (AE) with neuronal surface antibodies (NSAbs) without tumor and explore the optimal course of corticosteroids.

Methods

Fifty-five patients with definite AE without tumor were enrolled consecutively between June 2015 and November 2020 and retrospectively divided three groups according to the course of treatment with corticosteroid, i.e., a group of patients with a course of 3-6 months (Group 3-6mo), 6-12 months (Group 6-12mo), and >12 months (Group >12mo). Demographic data, clinical manifestation and ancillary tests results were recorded. The dosage and courses of corticosteroid treatment, the recovery of neurological function, the occurrence of adverse effects, and relapses were followed up.

Results

A total of 55 patients were included in the final analysis. The numbers of patients in Group 3-6 mo, Group 6-12 mo, and Group >12 mo was 14, 17, and 24, respectively. A significantly higher proportion of patients in Group >12 mo showed a decreased level of consciousness at the onset (12, 50%) than in Group 3-6 mo and Group 6-12 mo (2,14.3%; 3, 17.6%) (p = 0.033). The incidence of MRI abnormalities was significantly higher in Group 6-12 mo and Group >12 mo (10, 58.8%; 16, 66.7%) than in Group 3-6 mo (3, 21.4%) (P=0.023). Ordinal regression analysis indicated that decreased level of consciousness was associated with the course of corticosteroid (OR=3.838, 95% CI: 1.103-13.323, P=0.035). No significant difference was observed between the three groups regarding the cumulative dose of corticosteroids administered during the first three months of long-term treatment (P>0.05). Additionally, no significant difference in the cumulative dosage of corticosteroids was found between patients in Group 6-12 months and Group >12 months during the first 6 months after beginning long-term treatment. The mRS scores of the three groups were not statistically significant before and after first-line treatment or at the last follow-up. Bonferroni multiple comparison test indicated that the mRS scores of patients in Group 6-12 months and Group >12 months were not statistically significant at 3 months and 12 months after the start of long-term treatment. During the follow-up, 50 (90.9%) patients achieved satisfactory neurological function (mRS score ≤2). Five patients (9.1%) experienced a first relapse and 2 of them were overlapped with both anti-NMDA receptor and glial antibodies. The incidence of adverse effects was significantly higher in Group >12 mo (17, 70.8%) than in Group 3-6 mo (3, 21.4%) and Group 6-12 mo (5, 29.4%) (P=0.003).

Conclusions

The beneficial effects of oral corticosteroid treatment may do not persist beyond 12 months and may even contribute to an increased incidence of adverse effects. In order to optimize the effectiveness and safety of treatment, we recommend a corticosteroid course of 3-12 months. Patients with reduced levels of consciousness may be more inclined to choose longer courses of corticosteroids for long-term treatment. Patients with an "overlapping syndrome" may require more intense immunotherapy to prevent relapse.

Approach to acute encephalitis in the intensive care unit

PURPOSE OF REVIEW

Recent years have seen a dramatic increase in the identification of autoimmune encephalitis (AE) and the emergence of new causes of infectious encephalitis (IE). However, management of these patients remains challenging, with many requiring care in intensive care units. Here, we describe recent advances in the diagnosis and management of acute encephalitis.

RECENT FINDINGS

Advances in the identification of clinical presentations, neuroimaging biomarkers, and electroencephalogram patterns have enabled more rapid diagnosis of encephalitis. Newer modalities such as meningitis/encephalitis multiplex PCR panels, metagenomic next-generation sequencing, and phage display-based assays are being evaluated in an effort to improve detection of autoantibodies and pathogens. Specific advances in the treatment of AE include establishment of a systematic approach to first-line therapies and the development of newer second-line modalities. The role of immunomodulation and its applications in IE are actively being investigated. In the ICU, particular attention to status epilepticus, cerebral edema, and dysautonomia may improve outcomes.

SUMMARY

Substantial diagnostic delays still occur, with many cases left without an identified etiology. Antiviral therapies remain scarce, and optimal treatment regimens for AE still need to be clarified. Nevertheless, our understanding of diagnostic and therapeutic approaches to encephalitis is rapidly evolving.

Phenotyping the late- and younger-onset neuronal surface antibody-mediated autoimmune encephalitis: a multicenter study

Neuronal surface antibody-mediated autoimmune encephalitis (NSAE) occurs across a wide age range. However, few studies focused on the onset age and their related characteristics. We aimed to explore the age-dependent profile of NSAE. A total of 134 patients with a definite diagnosis of NSAE were retrospectively enrolled from 3 tertiary hospitals between July 2014 and August 2020. Demographic, clinical, therapeutic, and prognostic data were collected and compared between the late- (≥45) and younger-onset (<45) groups. The results showed that 56 (41.8%) patients were classified as late-onset NSAE, and 78 (58.2%) as younger-onset NSAE. There were more males, especially in the late-onset group (P = 0.036). Prodromal symptoms were more common in the younger-onset group (P = 0.004). Among the onset symptoms, more late-onset patients presented as seizures, while more younger-onset patients presented as psychiatric symptoms. Throughout the disease course, the late-onset patients were more likely to have memory dysfunction (P < 0.001), but less likely to have central hypoventilation (P = 0.045). The late-onset patients also had a significantly lower modified Rankin Scale score on admission (P = 0.042), required intensive care unit (ICU) admission less frequently during hospitalization (P = 0.042) and had a shorter hospital stay (P = 0.014). Our study revealed that the late- and younger-onset NSAE had a distinct spectrum of demographic features, presentations, and prognoses. More attention is needed for the younger-onset patients, given a higher disease severity on admission, more frequent requirement for ICU admission and longer length of stay.

Performance of the clinical assessment scale for autoimmune encephalitis in a pediatric autoimmune encephalitis cohort

Background

The Clinical Assessment Scale for Autoimmune Encephalitis (CASE), a new scale used for rating the severity of autoimmune encephalitis (AE), has demonstrated good validity and reliability in adults with AE, but there is a shortage of data on its performance in children with AE. This study aimed to assess the reliability and validity of the CASE in a cohort of children with AE.

Methods

Forty-seven pediatric inpatients with AE who visited Guizhou Provincial People’s Hospital between January 1, 2017, and October 31, 2021, were enrolled in the study. The CASE and mRS scores were obtained through a review of detailed medical records from the Health Information System by two pediatric neurologists. Finally, the performance of the CASE in this pediatric AE cohort was analyzed.

Results

The results showed that anti-NMDA receptor encephalitis was the most common (61.70%) type of AE in children. The most common clinical manifestations were language problems (85.1%), psychiatric symptoms (80.9%), and dyskinesia/dystonia (78.7%). The CASE had good item reliability and interevaluator reliability; the Cronbach’s alpha value of the total score was 0.825, and the intraclass correlation (ICC) was 0.980. The Cronbach’s alpha value by item ranged from 0.16 to 0.406; items 1 and 9 had the lowest and highest Cronbach’s alpha values, respectively. The criterion validity between CASE and mRS total scores, as quantified by Pearson correlation, was 0.459, indicating slight to good criterion validity. The area under the curve (AUC) was 0.992 (95% confidence interval: 0.974-1.00). A cutoff value of 14 was selected to determine whether a patient needed admission to the ICU; this cutoff had a sensitivity of 100% and a specificity of 92%. The changes in EEG, MRI, and antibody titers were not related to the severity of AE. A CASE score cutoff of 9 was selected to indicate whether second-line treatment would be needed.

Conclusion

The CASE has good reliability and validity in children with AE; however, some items of the CASE may not apply to this population. Thus, an in-depth study of the CASE is needed in children with AE.

Case Report: Paroxysmal hyperhidrosis as an initial symptom in a patient with anti-LGI1 encephalitis

Anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis is the second most common cause of autoimmune encephalitis and is characterized by cognitive impairment, psychiatric disorders, and faciobrachial dystonic seizures. In recent decades, literature reports have expanded the phenotypic spectrum associated with the LGI1 autoantibody. The present report describes the case of a 58-year-old man who presented with repetitive unilateral hyperhidrosis of the body and arm as an initial symptom and gradually developed psychiatric symptoms, involuntary movements of the face and arms, and progressive cognitive decline. Anti-LGI1 antibodies were positive in both the serum and cerebrospinal fluid at approximately 2 months after symptom onset, and the patient was, therefore, diagnosed with anti-LGI1 encephalitis. His symptoms, namely hyperhidrosis and involuntary movements, were not relieved by antiepileptic drug treatment, but responded favorably to high-dose steroid therapy and intravenous immunoglobulin. We interpreted the repetitive unilateral hyperhidrosis as possible epilepsy. Based on this case, unilateral hyperhidrosis of the body and arm as a rare neurological presentation can be added to the phenotypic spectrum of anti-LGI1 encephalitis, and early recognition of this manifestation might support timely diagnosis and treatment.

Coexistence of multiple anti-neuronal antibodies in autoimmune encephalitis in China: A multi-center study

Background

Given that the combination of multiple antibodies in autoimmune encephalitis (AE) is rare and its clinical significance is unclear, this study aimed to investigate the clinical characteristics and significance of overlapping multiple anti-neuronal antibodies in patients with AE.

Methods

We conducted a retrospective analysis of the clinical characteristics, treatment, and prognostic details of 22 patients with multiple coexisting antibodies from multiple clinical centers in China.

Results

Among the 276 patients who were AE antibody-positive, 22 (7.97%) had two or more antibodies. Among the 22 patients with coexisting AE-related antibodies, 14 patients (63.63%) were combined of cell surface and intracellular antibody, and the remaining 8 patients (36.36%) were detected to be cell surface antibody positive only. The main symptoms of the 22 patients in this cohort included fever, seizures, memory impairment, cognitive decline, and sleep disorders. Five (22.73%) patients had tumors, among whom four had small-cell lung cancers, and one had mediastinal tumors. A total of 20 patients were treated with steroids and intravenous immunoglobulin, and 18 showed varying degrees of symptomatic improvement after first-line immunotherapy. Three patients died of tumor progression or chemotherapy complications.

Conclusion

The coexistence of multiple anti-neuronal antibodies in patients with AE may cause a superimposition and diversification of clinical manifestations. Combined paraneoplastic antibody positivity may be suggestive of an underlying malignancy.

First-line immunotherapy of neuronal surface antibody-mediated autoimmune encephalitis: Assessment of therapeutic effectiveness and cost-efficiency

OBJECTIVE

To evaluate the therapeutic effectiveness and cost-efficiency of first-line immunotherapies on neuronal surface antibody-mediated autoimmune encephalitis (AE) based on a real-world observational study in China.

METHODS

Our study retrospectively collected the clinical and paraclinical data of patients with definite neuronal surface antibody-mediated AE between July 2014 and July 2020. Regular follow-up was performed after administering standard regimens of first-line immunotherapies, including intravenous methylprednisolone (IVMP) and / or intravenous immunoglobulin (IVIG). Therapeutic effectiveness was reflected by modified Rankin Scale scores. The health resource utilization and direct medical costs were extracted to analyze the cost-efficiency.

RESULTS

Among the 78 eligible patients, 48 (61.5%) were males with a median age of 40 years. More than half (56, 71.8%) were treated with combination therapy, with the rest receiving IVMP and IVIG monotherapy (both of 11, 14.1%). Related objective variables, i.e., sex, onset age, disease course, onset symptoms, antibody types, abnormal paraclinical results, disease severity, and the health insurance, showed insignificant differences on the selection of therapy. Each therapy showed similar short-term (4-week) and long-term (1-year) therapeutic effects. Yet the single or combination of IVIG had a slightly better effectiveness but higher cost than the monotherapy of IVMP.

CONCLUSION

The combination of IVMP and IVIG was used more frequently than either alone, which may be associated with neurologist's personal experience and patient's wishes. Though with similar therapeutic effectiveness, the use of IVMP alone might be a better choice with a better cost-efficiency.

The Neutrophil-to-Lymphocyte and Monocyte-to-Lymphocyte Ratios Are Independently Associated With the Severity of Autoimmune Encephalitis

Background

The neutrophil-to-lymphocyte ratio (NLR) and monocyte-to-lymphocyte ratio (MLR) are biomarkers that may reflect inflammatory status in some immune-related diseases. This study aims to investigate the association of NLR and MLR with the severity and prognosis of autoimmune encephalitis (AE).

Methods

A total of 199 patients diagnosed with AE in the First Affiliated Hospital of Zhengzhou University from October 2015 to October 2021 were retrospectively analyzed. The Clinical Assessment Scale for Autoimmune Encephalitis (CASE) and the modified Rankin Scale (mRS) were used to evaluate the severity of the patients at admission, and the patients were divided into mild group (CASE ≤ 4) and severe group (CASE ≥ 5) according to the CASE score. Poor prognosis was described as an mRS of 3 or more at 12 months. Binary logistic regression analysis was performed to assess risk factors for the severity and prognosis of AE.

Results

NLR and MLR of severe group were significantly higher than that of mild group. NLR and MLR were positively correlated with the CASE score (r = 0.659, P < 0.001; r = 0.533, P < 0.001) and the mRS score (r = 0.609, P < 0.001;r = 0.478, P < 0.001) in AE patients. Multivariate logistic analysis showed that NLR (OR = 1.475, 95%CI: 1.211-1.796, P < 0.001) and MLR (OR = 15.228, 95%CI: 1.654-140.232, P = 0.016) were independent risk factors for the severity of AE. In addition, the CASE score and the mRS score were positively correlated (r = 0.849, P < 0.001). Multivariate logistic analysis showed that the CASE at admission (OR = 1.133, 95%CI: 1.043-1.229, P = 0.003) and age (OR = 1.105, 95%CI: 1.062-1.150, P < 0.001) were independent risk factors for the poor prognosis of AE patients. The NLR and MLR at admission and whether they decreased after immunotherapy were not associated with the prognosis of AE patients (P > 0.05).

Conclusions

NLR and MLR, readily available and widespread inflammatory markers, were helpful for clinicians to monitor disease progression and identify potentially severe patients of AE early to optimize clinical treatment decisions.

Risk Prediction Models for Early ICU Admission in Patients With Autoimmune Encephalitis: Integrating Scale-Based Assessments of the Disease Severity

Background

In patients with autoimmune encephalitis (AE), the prediction of progression to a critically ill status is challenging but essential. However, there is currently no standard prediction model that comprehensively integrates the disease severity and other clinical features. The clinical assessment scale in autoimmune encephalitis (CASE) and the modified Rankin Scale (mRS) have both been applied for evaluating the severity of AE. Here, by combining the two scales and other clinical characteristics, we aimed to investigate risk factors and construct prediction models for early critical care needs of AE patients.

Methods

Definite and probable AE patients who were admitted to the neurology department of Tongji Hospital between 2013 and 2021 were consecutively enrolled. The CASE and mRS scores were used to evaluate the overall symptom severity at the time of hospital admission. Using logistic regression analysis, we analyzed the association between the total scores of the two scales and critical illness individually and then we evaluated this association in combination with other clinical features to predict early intensive care unit (ICU) admission. Finally, we constructed four prediction models and compared their performances.

Results

Of 234 patients enrolled, forty developed critical illness and were early admitted to the ICU (within 14 days of hospitalization). Four prediction models were generated; the models were named CASE, CASE-plus (CASE + prodromal symptoms + elevated fasting blood glucose + elevated cerebrospinal fluid (CSF) white blood cell (WBC) count), mRS and mRS-plus (mRS + prodromal symptoms + abnormal EEG results + elevated fasting blood glucose + elevated CSF WBC count) and had areas under the ROC curve of 0.850, 0.897, 0.695 and 0.833, respectively. All four models had good calibrations. In general, the models containing “CASE” performed better than those including “mRS”, and the CASE-plus model demonstrated the best performance.

Conclusion

Overall, the symptom severity at hospital admission, as defined by CASE or mRS, could predict early ICU admission, especially when assessed by CASE. Adding other clinical findings, such as prodromal symptoms, an increased fasting blood glucose level and an increased CSF WBC count, could improve the predictive efficacy.

Clinical Features, Treatment, and Prognostic Factors in Neuronal Surface Antibody-Mediated Severe Autoimmune Encephalitis

Objective

This study aimed to determine the clinical characteristics and evaluate the efficacy of immunotherapy and the long-term prognosis of severe autoimmune encephalitis (AE) in China.

Methods

Clinical features, laboratory or radiological findings, and treatment outcomes of 60 severe patients with AE from January 1, 2014, to December 31, 2020, were collected. Continuous variables were compared using the t-test and the nonparametric Mann–Whitney U test, as appropriate. Univariate and multivariable logistic regression analyses were performed to assess the correlations between factors, treatment responses, and prognosis of severe AE.

Results

The median age of symptom onset was 35 years. Tumors were identified in 23.3% of patients, and 36/60 (60%) patients responded to first-line immunotherapy. Second-line immunotherapy was implemented in 26/60 (43.3%) patients. A significant clinical benefit was observed in 19/26 (73.1%) patients treated with lower dosage rituximab; seven patients were still refractory and received bortezomib as an add-on therapy. During the last follow-up, 48/60 (80%) patients achieved good outcomes (mRS, 0–2), and 10 died. Seventeen patients experienced relapses. A high CD19⁺ B-cell count (OR, 1.197; 95% CI [1.043–1.496]; p = 0.041) and a lower neutrophil-to-lymphocyte ratio (NLR; OR, 0.686; 95% CI [0.472–0.884]; p = 0.015) predict the response to first-line treatment and good prognosis, respectively.

Conclusions

Patients with severe AE were in critical condition at baseline but could be salvaged after effective rescue immunotherapy. A lower dosage of rituximab could be an optimal option for severe AE. CD19⁺ B-cell count and NLR may provide prognostic information for predicting treatment response and outcome of severe AE.

Validation of the Clinical Assessment Scale in Autoimmune Encephalitis in Chinese Patients

Background and Objectives

The Clinical Assessment Scale in Autoimmune Encephalitis (CASE) is a scale for assessing severity in autoimmune encephalitis. We aimed to validate the CASE score in a Chinese population and evaluate its clinical significance.

Methods

Patients diagnosed with autoimmune encephalitis were recruited between June 2014 and May 2019 from two hospitals. CASE and modified Rankin Scale (mRS) scores were obtained. Data regarding clinical features, treatment, and available information were gathered from the hospital information system.

Results

Of the 176 patients with autoimmune encephalitis, 11 died and 14 had tumors. Ten patients received second-line treatment. The CASE scores of patients receiving second-line treatment were significantly higher (median CASE: 15) than in those receiving first-line treatment (median CASE: 8) (p<0.001). Twenty-two patients had poor functional status (mRS>2). Areas under the curve of CASE on whether functional status was poor at 1 year were 0.89 (p<0.001). Sixty patients were admitted to the intensive care unit (ICU), and the CASE scores were positively correlated with days in the ICU (r=0.58, p<0.001). There was no statistically significant association between the CASE scores and relapse (p=0.39>0.05). Additionally, the CASE scores were positively associated with the mRS scores (r=0.85 p<0.001).

Conclusions

The CASE score is suitable for the comprehensive assessment of Chinese patients with autoimmune encephalitis, which may help clinicians to select the appropriate intervention and estimate the disease severity and prognosis.

Clinical Features and Therapeutic Effects of Anti-leucine-rich Glioma Inactivated 1 Encephalitis: A Systematic Review

Background: Clinical presentations and treatment programs about anti-leucine-rich glioma inactivated 1 (LGI1) encephalitis still remain incompletely understood. Objective: This study analyzed the clinical features and therapeutic effects of anti-LGI1 encephalitis. Methods: PubMed, EMBASE, and the Cochrane Library were searched to identify published English and Chinese articles until April 2021. Data were extracted, analyzed, and recorded in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Results: A total of 80 publications detailing 485 subjects matched our inclusion criteria. Short-term memory loss (75.22%), faciobrachial dystonic seizures (FBDS) (52.53%), other seizures excluding FBDS (68.48%), psychiatric symptoms (57.67%), and sleep disturbances (34.30%) were the most frequently described symptoms in anti-LGI1 encephalitis. Hyponatremia (54.90%) was the most common hematologic examination change. The risk of incidence rate of malignant tumors was higher than in healthy people. The positive rate of anti-LGI1 in serum (99.79%) was higher than CSF (77.38%). Steroids (93.02%), IVIG (87.50%), and combined use (96.67%) all had a high remission rate in the initial visit. A total of 35 of 215 cases relapsed, of which 6/35 (17.14%) did not use first-line treatment, and 21 (60.00%) did not maintain long-term treatment. Plasma exchange (PE) could be combined in severe patients, immunosuppressant could be used for refractory patients or for recurrence and using an anti-epileptic drug to control seizures may benefit cognition. Conclusions: Short-term memory loss, FBDS, psychiatric symptoms, and hyponatremia were key features in identifying anti-LGI1 encephalitis. Serum and CSF antibody tests should be considered in diagnosis criteria. Steroids with IVIG should be recommended, PE was combined for use in severe patients, immunosuppressant therapy might improve outcomes if recurrence or progression occurred, and control seizures might benefit cognition. The useful ways to reduce relapse rate were early identification, clear diagnosis, rapid treatment, and maintaining long-term treatment. The follow-up advice was suggested according to the research of paraneoplastic syndrome, and concern about tumors was vital as well.

Clinical Characteristics and Short-Term Prognosis of Children With Antibody-Mediated Autoimmune Encephalitis: A Single-Center Cohort Study

BACKGROUND

The incidence and prevalence of autoimmune encephalitis (AE) is gradually increasing in pediatric patients (between the ages of 3 months and 16 years). The aim of this retrospective observational study was to investigate the clinical characteristics and short-term prognosis of children with antibody-mediated AE at Hunan Children's Hospital.

METHODS

Antibody analysis of blood and/or cerebrospinal fluid was performed in suspected AE patients admitted to the Department of Neurology, Hunan Children's Hospital from June 2014 to June 2021. Ultimately, 103 patients were diagnosed with antibody-mediated AE and were enrolled in this study. Clinical data and corresponding demographic, clinical characteristics, laboratory and imaging data, treatment, and prognosis data were collected and analyzed.

RESULTS

In our study, 103 AE patients with antibody-positive were identified. The main subtype of AE in our cohort was anti-NMDAR encephalitis. Few patients have anti-CASPR2 encephalitis, anti-GABABR encephalitis, or anti-LGI1 encephalitis. In our AE patients, the most common clinical manifestations were behavioral symptoms, seizures, and involuntary movements, with seizures being the most common initial symptom. All patients underwent brain magnetic resonance imaging (MRI) and electroencephalography (EEG). Forty-five (43.7%) patients had abnormal MRI findings. And 96 (93.2%) patients had abnormal EEG results. All 103 patients were given first-line immunotherapy, 21 of which were also treated with the combination of the second-line immunotherapy. All surviving patients were followed up for at least 6 months. Seventy-seven patients recovered completely, 23 had sequelae of different degrees, and 3 died. Eight patients had one or more relapses during the follow-up period.

CONCLUSIONS

AE is a treatable disease that can occur in children of all ages. The mortality rate is low, as most patients have a good response to immune therapy. Compared with the older children, infants and young children (≤ 3 years old) with anti-NMDAR encephalitis have a higher incidence of fever and status epilepticus, more severe condition, higher PICU admission rate and worse prognosis. AE patients with high maximum mRS scores and PICU admissions may require second-line immunotherapy.

Role of Increased Syncytin-1 Expression in Pathogenesis of Anti-N-Methyl-d-Aspartate Receptor Encephalitis

PURPOSE

Syncytin-1 may play a role in several neuropsychiatric disorders, but its function in anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is unknown. The purpose of this study was to examine the possible mechanism of action of syncytin-1 in patients with anti-NMDAR encephalitis.

PATIENTS AND METHODS

Twenty patients with anti-NMDAR encephalitis and eight controls were recruited. The protein levels of syncytin-1 in serum were determined using an enzyme-linked immunosorbent assay, and the transcript levels of syncytin-1 were determined using real-time quantitative PCR. Flow cytometry was used for peripheral blood lymphocyte subset detection. Further, the relationship between syncytin-1 levels and clinical features of anti-NMDAR encephalitis and peripheral blood lymphocyte subsets was analyzed.

RESULTS

Compared with those in controls, higher syncytin-1 levels and percentage of B cells (CD3-CD19+) were observed in patients with anti-NMDAR encephalitis. Among anti-NMDAR encephalitis patients, the level of syncytin-1 positively correlated with the proportion of B cells and modified Rankin scale score at onset and after immunotherapy and negatively correlated with the proportion of CD3+ T cells.

CONCLUSION

An increased expression of Syncytin-1 is associated with the pathogenesis of anti-NMDAR encephalitis, providing evidence for elucidating the pathogenesis of the disease and suggesting novel therapeutic targets. Further, this study clarifies the role of syncytin-1 in neuroimmune disorders.

The LGI1 protein: molecular structure, physiological functions and disruption-related seizures

Leucine-rich, glioma inactivated 1 (LGI1) is a secreted glycoprotein, mainly expressed in the brain, and involved in central nervous system development and physiology. Mutations of LGI1 have been linked to autosomal dominant lateral temporal lobe epilepsy (ADLTE). Recently auto-antibodies against LGI1 have been described as the basis for an autoimmune encephalitis, associated with specific motor and limbic epileptic seizures. It is the second most common cause of autoimmune encephalitis. This review presents details on the molecular structure, expression and physiological functions of LGI1, and examines how their disruption underlies human pathologies. Knock-down of LGI1 in rodents reveals that this protein is necessary for normal brain development. In mature brains, LGI1 is associated with Kv1 channels and AMPA receptors, via domain-specific interaction with membrane anchoring proteins and contributes to regulation of the expression and function of these channels. Loss of function, due to mutations or autoantibodies, of this key protein in the control of neuronal activity is a common feature in the genesis of epileptic seizures in ADLTE and anti-LGI1 autoimmune encephalitis.

Clinical Relevance of Cerebrospinal Fluid Antibody Titers in Anti-N-Methyl-d-Aspartate Receptor Encephalitis

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is the most common autoimmune encephalitis. To date, there has been no study on the relationship between antibody (Ab) titers and clinical phenotype. This study aims to clarify the relationship between cerebrospinal fluid Ab titers and clinical manifestations of anti-NMDAR encephalitis at onset. Seventy-six consecutive patients with a definite diagnosis were enrolled. The relationship between Ab titers and different onset symptoms including psychiatric symptoms, seizures, and memory deficits were analyzed. We further investigated the correlation between Ab titers and clinical severity as assessed by the modified Rankin scale (mRS) and the clinical assessment scale for autoimmune encephalitis (CASE), respectively. The Ab titers had a median value of 1:10 (range 1:1–1:100). There was no significant difference in titers among various clinical factors including gender and combination of tumor and other diseases (each p > 0.05). Patients presenting with psychiatric symptoms at onset had higher titers than those with seizures (p = 0.008) and memory deficits (p = 0.003). The mRS scores revealed a significant but weak correlation with Ab titers (r = 0.243, p = 0.034), while CASE scores did not correlate with the titers (p = 0.125). Our findings indicated that the Ab titers were associated with the type of onset symptoms, with a higher level of patients with psychiatric symptoms. Regarding the clinical severity, the titers showed a weak correlation with the mRS, but no correlation with the CASE.

Efficacy and tolerability of intravenous immunoglobulin versus intravenous methylprednisolone treatment in anti- N-methyl-D-aspartate receptor encephalitis

OBJECTIVES

To compare the effectiveness and safety of intravenous immunoglobulin (IVIg) or intravenous methylprednisolone (IVMP) vs and IVIg plus IVMP (IPI) as initial therapy in anti- N-methyl-D-aspartate receptor (NMDAR) encephalitis.

METHODS

A multicenter study of prospectively identified NMDAR encephalitis individuals who presented from October, 2011, to August, 2020, to the study hospitals of western China, with a median follow-up of 3.9 years. Prespecified candidate variables were the prescriptions of IVIg, IVMP, or a combination of both. Propensity score matching was also performed to control potential confounders.

RESULTS

A total of 347 NMDAR encephalitis patients were finally analyzed in this study. After the TriMatch for NMDAR encephalitis, 37 triplets were generated. Compared to IVIg or IVMP, the administration of IPI exhibited a significant benefit of a higher response rate (86.5% vs. 55.6% vs. 68.7%, p^corr <0.01); improved mRS score at 3, 6, and 12 months (p^corr <0.05); and reduced further recurrence rate (10 of 37 [27.0%] vs 9 of 37 [24.3%] vs 2 of 37 [5.4%]; p log rank = 0.01). There was no association between treatment superiority and patient sex or the presence of tumors (p≥0.05). Patients treated with IVMP had a significantly higher number of adverse events, but 99% of adverse events were mild to moderate and did not lead to a change in treatment.

CONCLUSION

In patients with NMDAR encephalitis, adequate response, favorable outcome, and less recurrence were each more likely to occur in individuals treated with a combined immunotherapy than in monotherapy individuals.