Antibody Positive Autoimmune Encephalitis Research Articles

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

ObjectiveThe objective was to utilize nine machine learning (ML) methods to predict the prognosis of antibody positive autoimmune encephalitis (AE) patients. MethodsThe 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. ResultsThe 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. LimitationsAs a rare disease, the sample size of this study is relatively small. ConclusionThe model constructed using RF and XGBoost has good performance, good discrimination, calibration, clinical applicability, and interpretability.

A comparison of infectious and autoimmune meningoencephalitis: Clinical presentation, biochemical markers and MRI findings

Objective: This study investigates distinguishing patterns in lesion distribution, relevant clinical presentation and biochemical markers in MRI to differentiate infective encephalitis (IE) and autoimmune encephalitis (AE). Methods: Retrospective study of adult patients with a confirmed diagnosis of IE and AE admitted to the Neurology unit from January 2012 to December 2020 with MRI Brain. Selected cases with confirmed IE (according to the 2013 Infective Encephalitis Consortium diagnostic criteria) or antibody-positive AE (detection of Neuronal auto-antibody from blood or CSF), coupled by clinical presentation. MRI brain lesion distribution, lobar involvement, enhancement, haemorrhage, vasculopathy and atrophy were analysed. Results: Forty-seven patients (21 IE and 26 AE, respectively) were selected. IE group are older (48.0 ± 16.81) compared to AE (28.4 ± 14.10). Fever and vomiting were significant in IE (p<0.001), whereas psychosis, seizure, movement disorder, and tumour (ovarian teratoma) were significant in the AE cohort. Cerebrospinal fluid (CSF) analysis showed elevated leucocytes with polymorphism and high protein levels in IE (2.081 g/L ± 2.93 vs AE (0.352g/L ± 0.18). MR imaging detected abnormal findings in 61.9% of cases with infectious encephalitis (IE), while 76.9% of cases with autoimmune encephalitis (AE) exhibited normal MRI results. Asymmetrical lesions and inferior frontal lobe distribution (57.1%) were significantly prevalent in IE (p<0.05). Enhancement patterns and haemorrhage were rarely observed in AE patients. Conclusion: IE presented at an older age, with the majority having MRI findings such as asymmetrical lesions, leptomeningeal enhancement, and involvement of medial temporal, hippocampus and inferior frontal cortex. IE clinically presents with fever, vomiting, and elevated CSF leucocytes and protein levels. AE presents at a younger age with seizure, psychosis, movement disorder, tumour (ovarian teratoma). Fewer AE have MRI findings, and if present, tend to be symmetrical in distribution. Lobar involvement in the inferior frontal was the MRI feature that significantly favoured the diagnosis of IE compared to AE. IE and AE have distinct clinical, biochemical, and MRI abnormalities that can be discriminated between the 2 entities.

Antibody-positive autoimmune encephalitis and paraneoplastic neurological syndrome: A Swedish case series.

This study aimed to explore the clinical characteristics and temporal disease course of patients with autoimmune encephalitis (AE) and paraneoplastic neurological syndrome (PNS) in Sweden. Thirty-seven antibody-positive AE and PNS cases were identified in the Healthcare region Mid Sweden between 2015 and 2019. Clinical data were collected through a retrospective review of electronic health records. Patients were divided into three subgroups based on antibody type: neuronal surface antibodies (NSAbs), onconeural antibodies, and anti-GAD65 antibodies. Nineteen patients had NSAbs, 11 onconeural antibodies, and seven anti-GAD65 antibodies. Anti-LGI1 and anti-NMDAR were the most frequently detected NSAbs, with anti-NMDAR cases having an older-than-expected age distribution (median age 40, range 17-72). Only 11 of 32 (30%) of patients had findings suggesting encephalitis on initial MRI, but 28 of 31 (90%) had pathological findings on initial cerebrospinal fluid analysis. All patients but one had abnormal EEG findings. Median time to immunotherapy was comparable among the three subgroups, whereas patients with anti-LGI1, anti-CASPR2, and anti-IgLON5 had an eightfold longer time to immunotherapy than anti-NMDAR and anti-GABA-B (p=.0016). There was a seasonal variation in onset for patients with non-tumor-related NSAbs and anti-GAD65 antibodies, with most patients (72%) falling ill in spring or summer. Swedish patients with AE and PNS had similar clinical characteristics as previously described cohorts from other geographical regions except for anti-NMDAR encephalitis, with older onset than expected. The onset of non-tumor-related AE occurred predominantly in the warm seasons, and AE with a more insidious onset was associated with delayed treatment initiation.

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

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. 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). 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. 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.

Seizures as Initial Presentation and Enduring Predisposition to Seizures in Autoimmune Encephalitis

Purpose. This retrospective study is aimed at investigating the clinical characteristics of autoimmune encephalitis (AE) and long-term prognosis of patients who initially present with seizures as well as risk factors for enduring predisposition to seizures in AE. Methods. From January 1, 2013, to October 31, 2021, a total of 343 AE patients from a single center diagnosed with autoimmune encephalitis (AE) were enrolled in this study, including 198 antibody-positive AE and 145 antibody-negative but probable AE. According to initial symptoms, AE patients were divided into two groups: onset with seizure group and onset with nonseizure group. The clinical characteristics were retrospectively reviewed. Patients were clinically evaluated at onset and at 6, 12, and 24 months of follow-up. Modified Rankin Scale (MRS) score, Clinical Assessment Scale in Autoimmune Encephalitis (CASE) score, and seizure-related information were assessed. Results. In AE, patients with seizures as the first presentation were younger, with a median-onset age of 28 years old. Compared with other types of antibody-positive AE, anti-GABABR AE more frequently began with seizures, while anti-CASPR2, anti-AMPAR, and anti-DPPX encephalitis usually began with symptoms other than seizures. The most common type of initial seizures in AE was focal to bilateral seizure (67.6%), with a significant prevalence in antibody-positive AE (P=0.001). In addition, compared with nonseizure group, patients with seizures as an initial presentation had higher MRS and CASE scores at 24 months of follow-up. Older age at onset and focal nonmotor seizure type were independent risk factors for an enduring predisposition to seizures in AE patients. Conclusion. The younger and anti-GABABR-positive AE patients are more prone to onset with seizures. AE patients who initially presented with seizures had worse long-term neurological recovery. Onset age and seizure type should be highly appreciated when formulating the strategy for therapy at post-AE status.

Contactin-associated protein-2 and anti-aquaporin-4 antibody positive autoimmune encephalitis secondary to herpes simplex encephalitis: A case report.

Recurrent herpes simplex encephalitis (HSE) can easily induce autoimmune encephalitis (AE). However, there are few reports of anti-contactin-associated protein-2 (CASPR2)-related encephalitis, especially with positive anti-aquaporin 4 (AQP4) antibodies. A 14-year-old boy was admitted to the Department of Neurology of the First Affiliated Hospital of Kunming Medical University for "headache, dizziness, and fever for four days" with positive anti-CASPR2 and anti-AQP4 antibodies in the cerebrospinal fluid. Cranial MRI showed lesions in the right hippocampus, amygdala, and insular lobe, with local sulcus enhancement in the right insular, temporal, and frontal lobes. The fluid-attenuated inversion recovery was significantly enhanced. Human herpes virus type I was detected by cerebrospinal fluid metagenomic testing. The patient was diagnosed with AE secondary to HSE, with positive anti-CASPR2 and anti-AQP4 antibodies. After 2 weeks of immunoglobulin and methylprednisolone immunomodulatory therapy, acyclovir antivirus, mannitol dehydration, reducing intracranial pressure, and other symptomatic support therapy. The patient's symptoms significantly improved, with no complaints of discomfort, and he was discharged for observation. The patient was followed up a month after discharge and had no complaints of discomfort. CASPR2 and anti-aquaporin-4 antibody-positive AE have not been reported to be positive. This case will raise awareness of CASPR2 and anti-aquaporin-4 antibody-positive AE secondary to HSE, strengthen diagnostic capacities, and provide advice to treat it.

Antibody-Positive Autoimmune Encephalitis and Paraneoplastic Neurological Syndrome: Epidemiology and Outcome of Neuronal Antibody Testing in Sweden

Objective. To estimate the 5-year incidence rate of autoimmune encephalitis (AE) and paraneoplastic neurological syndrome (PNS) in Sweden. Methods. All patients who were tested for a neuronal antibody in Sweden between 2015 and 2019 were included. Patients in Healthcare region Mid Sweden (population 2.1 million) were invited to participate in a case ascertainment substudy. AE and PNS cases were defined using established diagnostic criteria. Crude and age-adjusted incidence rates of AE and PNS in Healthcare region Mid Sweden were estimated. Results. The number of tests for neuronal antibodies in Sweden increased between 2015 and 2019 from 1867 to 2505 (serum) and 863 to 1376 (CSF) per annum. The frequencies of positive results were stable over the entire study period, and the mean value was 6.1% for serum (CI95% 5.5–6.7) and 4.8% for CSF (CI95% 4.0–5.6). In total, 125 patients tested positive for neuronal antibodies in Healthcare region Mid Sweden between 2015 and 2019. Of these, 94 were included, and after case ascertainment, thirty-one cases of definite AE or PNS could be identified. The 5-year incidence rate of AE and PNS was 3.0 per million person-years (95% CI 1.9-4.1). The yearly incidence rates increased in the study period, from 1.5 per million person-years in 2015 (95% CI 0.0-3.2) to 4.3 per million person-years in 2019 (95% CI 1.5-7.1). Conclusions. In this first epidemiological study of AE and PNS in Sweden, the number of cases doubled from 2015 to 2019. This likely reflects increased availability of testing and awareness of these conditions.

Evaluation of multiple consensus criteria for autoimmune encephalitis and temporal analysis of symptoms in a pediatric encephalitis cohort.

ObjectiveTo evaluate the sensitivity and specificity of current criteria for the diagnosis of autoimmune encephalitis (AE) and the temporal onset of neuropsychiatric symptoms (NP) in a pediatric encephalitis cohort.BackgroundMultiple criteria for AE have been developed, including the Graus and pediatric-focused Cellucci consensus criteria, and the Determining Etiology in Encephalitis (DEE) score for patients with encephalitis. Early identification and treatment of AE is crucial to improve outcomes, but this can be difficult given the frequent overlap of clinical presentation between AE and infectious encephalitis (IE).Design/methodsA retrospective review was conducted of patients seen at our institution from 2000 to 2021 with a final diagnosis of AE or IE. These were narrowed through multiple exclusions to etiology-confirmed IE or antibody-positive/negative AE. Time of onset or results of all symptoms and diagnostics were recorded. Sensitivity and specificity of each criterion under various clinical scenarios were calculated over the first month after initial NP symptom onset.ResultsA total of 23 antibody-positive AE, 9 antibody-negative AE and 23 IE patients were included in final analysis. Under an idealized scenario with rapid initial diagnostic evaluations, the sensitivity for pediatric AE by day 28 after onset of NP symptoms approached 90% for both Cellucci and Graus criteria. Specificity within these 28 days was low without infectious testing results, increasing the greatest with rapid PCR testing and second with infectious antibody testing—reaching ~90% with both. A DEE score of 3 provided a specificity of 100% in identifying IE, but low sensitivity (29%). Symptoms were noted to cluster within several days of onset in IE, but in AE were spread out. Personality/behavioral change, speech change, affective disorder, and sleep disturbance were noted more often in AE, while fever, elevated C-reactive protein or CSF protein, and abnormal MRI-Brain occurred more often in IE.ConclusionIn this study, we provide the first evaluation of the Cellucci criteria and the first validation of the DEE score in the differentiation of pediatric AE and IE. Further refinement of AE criteria is needed to improve early detection and treatment of pediatric AE.

Clinical validation of the 2020 diagnostic approach for pediatric autoimmune encephalitis in a single center

Objective: To evaluate the value of the 2020 diagnostic criteria (Cellucci criteria) for pediatric autoimmune encephalitis (AE) in children with suspected AE in a single center. Methods: The clinical data of 121 children hospitalized at the First Affiliated Hospital of Zhengzhou University from October 2019 to October 2021, with a diagnosis of suspected AE, were retrospectively collected and analyzed. The children were divided into definite antibody-positive AE (dAPAE), probable antibody-negative AE (prANAE), possible AE (pAE) and non-AE groups according to the Chinese expert consensus and the Graus criteria. A new diagnosis was made according to the Cellucci criteria which was compared with the clinical diagnosis to evaluate the diagnostic value of the Cellucci criteria. The Mann-Whitney U test, Kruskal-Wallis test, and χ2 test were used to compare the differences among groups. The sensitivity and specificity were used to evaluate efficacy of the Cellucci criteria. Results: Among the 121 children, 72 were males and 49 were females, with an age of 10.3 (6.5, 14.0) years at disease onset. There were 99 cases diagnosed as AE according the clinical diagnosis (58 males and 41 females), of which 43 cases were diagnosed as dAPAE, 14 cases as prANAE and 42 cases as pAE, and the other 22 cases were not AE (14 males and 8 females). The top 2 initial symptoms in the 99 children with AE were seizures (53 cases, 53.5%) and abnormal mental behaviors (35 cases, 35.4%). And the most common symptoms during the course of the disease were abnormal mental behaviors (77 cases, 77.8%) and seizures (64 cases, 64.6%). There were statistically differences in the incidence of consciousness disorders, autonomic dysfunctions during the course of the disease and the length of hospitalization among the 4 groups (χ2=21.63, 13.74, H=22.60, all P<0.05). Ninety-six of the 121 children were tested for AE-related antibodies, of which 45 cases (46.9%) were antibody-positive. According to the Cellucci criteria, 42 cases were diagnosed as dAPAE, 34 cases as prANAE and 14 cases as pAE. Compared with the clinical diagnosis, the sensitivity of the Cellucci criteria for the diagnosis of the 3 types of AE were 93.02%, 92.86% and 87.88%, and the specificity were 96.23%, 74.39% and 86.36%, respectively. Conclusions: The Cellucci criteria has a high sensitivity and specificity for the diagnosis of pAE and dAPAE in the clinical management of children with suspected AE, while a high sensitivity but low specificity for the diagnosis of prANAE. Therefore, it is recommended to apply the Cellucci criteria selectively in clinical practice according to the actual situation, especially in the diagnosis of prANAE.

Cerebrospinal Fluid Extracellular Vesicles with Distinct Properties in Autoimmune Encephalitis and Herpes Simplex Encephalitis

Encephalitis mediated by autoantibodies against neuronal antigens and herpes simplex encephalitis (HSE) are seemingly separate causes of encephalopathy in adults. Autoimmune encephalitis (AE) is autoimmune in origin, and herpes simplex encephalitis is infectious. The purpose of this study was to examine the role of cerebrospinal fluid (CSF) exosomes from patients with antibody-positive AE and HSE. Towards this, exosomes were isolated from CSF from 13 patients with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, 11 patients with anti-gamma-aminobutyric acid-B (GABAB) receptor encephalitis, 9 patients with anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis, and 8 patients with anti-contactin-associated protein-like 2 (CASPR2) encephalitis, and 12 control individuals negative of antibodies against neuronal autoantigens. There were ten miRNAs highly expressed in patients with anti-NMDAR encephalitis compared to those in control subjects. Eight miRNAs were found to be lower expressed in anti-NMDAR encephalitis CSF-derived exosomes. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enriched by AE differential expressed exosomic miRNAs demonstrated that AE-related exosomic miRNAs may participate as a feedback regulation in cancer development. In addition, the exosome concentration in CSF of 9 HSE patients was significantly higher compared to those from 9 HSV( −) patients. This observation was consistent with the results that exosome concentration was found to be higher in the animal model which was inoculated intranasally with HSV-1 compared to controls. Furthermore, western blot demonstrated that the subunits of NMDAR, GABABR, and AMPAR were detected highly expressed in exosomes derived from sera of HSV-1-treated animal model compared to controls. More importantly, exosomes isolated from CSF of HSE patients contained higher expression levels of two miRNAs encoded by HSV, miR-H2-3p, and miR-H4-3p compared to those from HSV( −) patients. In summary, HSV may trigger brain autoimmunity in HSE by presentation of surface autoantigens via exosomes.

Predictors and prognoses of epilepsy after anti-neuronal antibody-positive autoimmune encephalitis

PurposeThis study aimed to investigate the incidence and predictors of epilepsy after anti-neuronal antibody-positive autoimmune encephalitis (AIE). The clinical outcomes of patients with epilepsy after AIE were also explored. MethodsA total of 111 AIE patients were retrospectively evaluated. Post-AIE epilepsy (PAEE) was defined as at least one unprovoked seizure occurring six or more months after discharge from hospital. ResultsThe incidence of acute symptomatic seizures was 80.2% (89/111) in our AIE patients. Furthermore, of the 89 AIE patients with seizures, 29 (32.6%) presented with seizures as the initial symptom. Overall, 44 out of 111 AIE patients (39.6%) had unprovoked seizures after six months, meeting our definition of PAEE. The independent risk factors for PAEE incidence included an initial presentation with new-onset refractory status epilepticus (NORSE), delayed immunotherapy treatment, the complication of a lung infection during admission, the requirement for mechanical ventilation during hospitalization, parietal lesions observed in magnetic resonance imaging (MRI), and focal slow waves on electroencephalographic (EEG) monitoring. ConclusionsEarly initiation of immunotherapy and lung infection treatment may reduce the risk of conversion of symptomatic seizures to chronic epilepsy in the acute phase of AIE. In general, PAEE patients could have a good prognosis if treated properly and in a timely fashion.

Potential autoimmune encephalitis following yellow fever vaccination: A report of three cases

Meningoencephalitis following yellow fever vaccination is considered a viral neuroinvasive disease. We describe three patients with typical autoimmune encephalitis syndromes that developed 1–27 days following yellow fever vaccination. Anti-N-methyl-d-aspartate-r antibodies were identified in the CSF and serum of two patients and the other case was associated with anti-neurexin-3 antibodies. One case was confirmed as vaccine-associated neurotropic disease due to reactive CSF yellow fever IgM, which suggested an infectious-autoimmune overlap mechanism. Two aditional cases of Anti-N-methyl-d-aspartate-r encephalitis were identified in the literature review. Antibody-positive autoimmune encephalitis should be included in the differential diagnosis of neurologic adverse events following yellow fever vaccination.

WITHDRAWN: fluid exosomes in paraneoplastic and autoimmune encephalitis: A possible feedback in cancer development

The purpose of this study was to examine the role of cerebrospinal fluid (CSF) exosomes from patients with paraneoplastic and autoimmune encephalitis (AE). Towards this, microRNA profiling in the exosomes which were isolated from cerebrospinal fluid of 12 patients with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis, 12 patients with anti-gamma-aminobutyric acid-B (GABAB) receptor encephalitis, 12 patients with anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis, and 12 patients with anti-contactin-associated protein-like 2 (CASPR2) encephalitis, and 12 control individuals negative of antibodies against neuronal auto-antigens. Selected findings were validated with quantitative RT-PCR. DIANA-mirPath was chosen for bioinformatic analysis. There were ten miRNAs higher expressed in AE patients with anti-NMDAR encephalitis compared to those in healthy controls. Further, eight miRNAs were found to be lower expressed in anti-NMDAR encephalitis CSF derived exosomes. In addition, Endometrial cancer, p53 signaling pathway, Non-small cell lung cancer, Small cell lung cancer, Transcriptional misregulation in cancer, Basal cell carcinoma, Acute myeloid leukemia, Renal cell carcinoma, Colorectal cancer, Choline metabolism in cancer, Melanoma, Pancreatic cancer, Prostate cancer, Ras signaling pathway, Glioma, Pathways in cancer, and Proteoglycans in cancer (all p < 0.01) were significantly enriched in differentially expressed miRNAs. Exosomes expressing specific miRNAs in antibody positive AE may participate as a feedback regulation in cancer development.

Spectrum of Anti-NMDA Receptor Antibody Encephalitis: Clinical Profile, Management and Outcomes.

Background:Anti-N-methyl D-aspartate receptor (anti NMDAR) antibody encephalitis is an immune-mediated entity characterised by a constellation of neuro-psychiatric symptoms.Objective:To describe clinical profile and treatment outcomes of patients with anti NMDAR antibody encephalitis.Settings and Design:Subjects were selected by screening for all patients satisfying Graus et al.'s criteria for probable anti NMDAR antibody encephalitis, admitted in neurology department of a tertiary care centre in Eastern India.Materials and Methods:A prospective, longitudinal study was conducted by identifying 25 patients with anti NMDAR antibodies in CSF and or serum, between September 2018 to February 2020.Statistical Analysis:Chi square test was used to compare variables.Results:Out of 98 patients screened, 25 subjects (14 females: 11 male) were positive for anti NMDAR autoantibodies, with a mean age of 17 years. 13 subjects belonged to paediatric age group. Most common presenting feature was memory/learning deficit (88%) followed by behavioural abnormalities (84%) and seizures (68%). 11 patients (44%) patients needed escalation to second line therapy, rituximab. Seven (28%) and twelve (48%) patients underwent complete (mRS 0-1) and partial recovery (mRS 2-3) respectively, while 4 (16%) became disabled (mRS 4-5). Mortality was 8%. Paediatric population had a better outcome in terms of disability (p = 0.043).Conclusion:Anti NMDAR-Ab encephalitis is the most common cause of antibody positive autoimmune encephalitis worldwide. There are important clinical markers and investigational profiles which carry prognostic significance.

An Australian State-Based Cohort Study of Autoimmune Encephalitis Cases Detailing Clinical Presentation, Investigation Results, and Response to Therapy.

Introduction: Autoimmune encephalitis is a disorder associated with antibodies directed against central nervous system proteins with variable clinical features. This study aims to add to knowledge of the disease by reporting the details of a cohort of patients with autoimmune encephalitis in Queensland, Australia.Methodology: We surveyed patients with autoimmune encephalitis diagnosed and managed through public hospitals in Queensland, Australia between 2010 and the end of 2019. Cases were identified via case detection through a centralized diagnostic neuroimmunology laboratory (Division of Immunology, HSQ Pathology Queensland Central Laboratory, Brisbane, Queensland, Australia) and a survey of neurologists. Data including demographic details, clinical presentation, investigation results, treatments including immune therapy and outcomes was collected.Results: Sixty cases of antibody positive autoimmune encephalitis were identified. Twenty-eight were of anti-NMDA-receptor encephalitis with other cases associated with antibodies against LGi1, Caspr2, glycine receptor, DPPX, GABAB receptor, IgLON5, GFAP, and SOX1. The number of diagnosed cases, especially of anti-NMDA-receptor encephalitis has markedly increased over the period 2017 to 2019. Clinical presentations were marked by heterogeneous symptom complexes and prolonged hospital admissions. Imaging studies were largely normal or non-specific. There was a response to immune therapy and a low mortality rate. Most cases affected by this disorder were left with ongoing symptoms associated with mild disability.Conclusion: Autoimmune encephalitis in Queensland, Australia is an increasingly common but complex clinical entity marked by heterogeneous presentations, response to immune therapy and outcome results marked by low mortality and incomplete recovery.

Seizures in autoimmune encephalitis-A systematic review and quantitative synthesis.

This study aimed to evaluate the proportion of patients with seizures and electroencephalography (EEG) abnormalities in autoimmune encephalitis (AE) and its most common subtypes. This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) standards and was registered with the International Prospective Register of Systematic Reviews (PROSPERO). We searched Medline All, Embase, and PsychINFO in Ovid from inception to June 2019 for articles pertaining to AE and seizure. Included studies reported seizure and/or EEG data in cohorts of ≥10 AE patients. Patient demographics, antibody type, seizure incidence, and EEG findings were extracted. Review of studies and data extraction were performed in duplicate. In addition to descriptive analysis, quantitative synthesis stratified by autoantibody subtype was performed with logistic regression and chi-square analyses. Our search yielded 3856 abstracts: 1616 were selected for full-text review and 118 studies met eligibility criteria. Of 3722 antibody-positive AE patients, 2601 (69.9%) had clinical seizures during the course of their illness. Of the 2025 patients with antibody-positive AE and available EEG data, 1718 (84.8%) had some EEG abnormality (eg, epileptiform discharges, slowing, and so on). Anti- N-methyl-d-aspartate (NMDA) receptor encephalitis (anti-NMDARE) was the most commonly reported type of AE (1985/3722, 53.3%). Of the anti-NMDARE patients with available seizure or EEG data, 71.8% (n=1425/1985) had clinical seizures during their illness, and 89.7% (n=1172/1306) had EEG abnormalities. For all AE patients and in the anti-NMDARE subpopulation, seizures were more common in younger patients (p<.05). This systematic review provides an estimate of the proportion of AE patients with seizures, confirming the magnitude of seizure burden in this population. Prospective studies are needed to understand population-based prevalence of seizures, identify factors associated with seizures, and evaluate particular EEG findings as biomarkers of seizures and outcomes in AE.

Exosomes expressing neuronal autoantigens induced immune response in antibody-positive autoimmune encephalitis

The immunological role of exosomes in autoimmune encephalitis (AE) remains uncharacterized and not examined. In this study we ought to determine whether exosomes are generated in AE and to define the presence of cell surface neuronal autoantigens (autoAgs) in the cargo. Exosomes were isolated from cerebrospinal fluid (CSF) from 12 patients with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis, 8 patients with anti-gamma-aminobutyric acid-B (GABAB) receptor encephalitis, 8 patients with anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis, 8 patients with anti-contactin-associated protein-like 2 (CASPR2) encephalitis, 10 patients with anti-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid 1,2 (AMPA) receptor encephalitis and 30 control individuals negative of antibodies against neuronal autoAgs. Western blot demonstrated that CSF or sera derived exosomes from AE contained specific neuronal autoAgs in protein aggregates, however, control subjects had no detectable levels of these neuronal autoAgs. In addition, development of antibodies against NMDAR, GABABR, LGI1, CASPR2, and AMPAR were detected in the sera after 30 days immunization of C57BL/6 J mice with exosomes isolated from antibody positive AE patients; Enzyme-linked immunospot (ELISpot) assay demonstrated increased frequency of neuronal autoAgs-specific IL-17 and IFN-γ in splenocytes from AE derived exosomes immunized mice. We concluded that exosomes expressing neuronal autoAgs were present in CSF from antibody positive AE patients, and we propose these exosomes carrying neuronal autoAgs would play an important role in the immune pathogenesis of autoimmune encephalitis.

Direct economic burden of patients with autoimmune encephalitis in western China.

ObjectiveTo analyze the cost of autoimmune encephalitis (AE) in China for the first time.MethodsPatients who were newly diagnosed with antibody-positive AE (anti-NMDA receptor [NMDAR], anti-γ aminobutyric acid type B receptor [GABABR], antileucine-rich glioma-inactivated 1 [LGI1], and anticontactin-associated protein-2 [CASPR2]) at West China Medical Center between June 2012 and December 2018 were enrolled, and a cost-of-illness study was performed retrospectively. Data on clinical characteristics, costs, and utilization of sources were collected from questionnaires and the hospital information system.ResultsOf the 208 patients reviewed, the mean direct cost per patient was renminbi (RMB) 94,129 (United States dollars [USD] 14,219), with an average direct medical cost of RMB 88,373 (USD 13,349). The average inpatient cost per patients with AE was RMB 86,810 (USD 13,113). The direct nonmedical cost was much lower than the direct medical cost, averaging RMB 5,756 (USD 869). The direct cost of anti-LGI1/CASPR2 encephalitis was significantly lower than that of anti-NMDAR encephalitis and anti-GABABR encephalitis. The length of stay in the hospital was significantly associated with the direct cost.ConclusionsThe financial burden of AE is heavy for Chinese patients, and there are significant differences between different types of AE.

Coexistence of Autoimmune Encephalitis and Other Systemic Autoimmune Diseases.

Background: In recent years, the phenomenon of coexisting systemic autoimmune diseases (ADs) in patients with autoimmune encephalitis (AE) has been increasingly found, while its clinical significance remains unexplored. This study aimed to investigate the types and potential clinical associations of autoimmune comorbidities in patients with antibody-positive AE.Methods: A retrospective cohort study of patients with antibody-positive AE was conducted from 2011 to 2018. The demographics, clinical characteristics, and follow-up data were reviewed.Results: We enrolled 517 patients, among whom 45 were affected by one or more types of ADs, including Hashimoto's thyroiditis (HT) (n = 28), systemic lupus erythematosus (SLE) (n = 3), anaphylactoid purpura (n = 3), vitiligo (n = 3), Sjögren's syndrome (SS) (n = 2), chronic urticaria (n = 2), bullous pemphigoid (n = 1), uveitis (n = 1), myasthenia gravis (MG) (n = 1), and the coexistence of SLE and anaphylactoid purpura (n = 1). The proportion of patients with coexisting ADs was higher in those with anti–leucine-rich glioma-inactivated 1 (LGI1) encephalitis than in those with anti–N-methyl-d-aspartate receptor (NMDAR) encephalitis (13/111 vs. 16/307) (P = 0.021). In anti-NMDAR and anti-LGI1 encephalitis patients, there were no significant differences in the age at onset, sex ratio, proportion of patients with tumors, disease severity, or recurrence between the groups with and without ADs.Conclusions: One or more types of ADs developed in AE patients, and patients with anti-LGI1 encephalitis had a higher frequency of autoimmune comorbidities than those with anti-NMDAR encephalitis. And we found that autoimmune comorbidities did not affect the clinical course of AE.

Proportion and spectrum of movement disorders in adolescent and adult patients of autoimmune encephalitis of non-neoplastic aetiology

We aimed to study the proportion of patients with movement disorders in seropositive autoimmune encephalitis of non-neoplastic aetiology and also to describe the spectrum of movement disorders in them.We prospectively screened 362 patients of age >12 years with encephalitis of unknown aetiology for a panel of antibodies for autoimmune encephalitis. Demographic and clinical characteristics with focus on the movement disorders were recorded. We also evaluated the differences in the spectrum of movement disorder based on various age groups and antibody positivity. Patients were treated with immune modulating drugs and were followed up for 6 months.Out of the 41 patients, 21 (51.2%) patients presented with movement disorder as a part of their clinical presentation. The commonest movement disorder encountered in our cohort was orofaciolingual dyskinesia (OFLD) 57.1% followed by tremor (38.1%), choreoathetosis (33.3%), paroxysmal dyskinesia (23.8%) stereotypies (14.3%), bradykinesia (13.1%), followed by dystonia (13.1%), catatonia (4.7%), neuromyotonia (4.7%) ballism (4.7%), ataxia (4.7%) and stiff person phenotype (4.7%). The hyperkinetic movement disorders were more commonly seen compared to hypokinetic disorders. All patients received immunomodulatory therapy. On follow, 17 (80.1%) patients had good response with total remission of the movement disorder. Four patients did not have total remission but significant improvement in the symptoms after 6 months of follow up.Our study shows that >50% of patients with antibody positive autoimmune encephalitis have movement disorder as a part of their clinical feature. Timely institution of immunotherapy leads to good outcome in majority of patients.