Clinical Features and Long-Term Outcomes of Anti-Leucine-Rich Glioma-Inactivated 1 Encephalitis: A Multi-Center Study

Predictors and Clinical Characteristics of Relapses in LGI1-Antibody Encephalitis

BACKGROUND AND OBJECTIVES

Relapses occur in 15%-25% of patients with leucine-rich glioma-inactivated 1 antibody (LGI1-Ab) autoimmune encephalitis and may cause additional disability. In this study, we clinically characterized the relapses and identified factors predicting their occurrence.

METHODS

This is a retrospective chart review of patients with LGI1-Ab encephalitis diagnosed at our center between 2005 and 2022. Relapse was defined as worsening of previous or appearance of new symptoms after at least 3 months of clinical stabilization.

RESULTS

Among 210 patients, 30 (14%) experienced a total of 33 relapses. The median time to first relapse was 23.9 months (range: 4.9-110.1, interquartile range [IQR]: 17.8). The CSF was inflammatory in 11/25 (44%) relapses, while LGI1-Abs were found in the serum in 16/24 (67%) and in the CSF in 12/26 (46%); brain MRI was abnormal in 16/26 (62%) relapses. Compared with the initial episode, relapses manifested less frequently with 3 or more symptoms (4/30 patients, 13% vs 28/30, 93%; p < 0.001) and had lower maximal modified Rankin scale (mRS) score (median 3, range: 2-5, IQR: 1 vs 3, range: 2-5, IQR: 0; p = 0.001). The median mRS at last follow-up after relapse (2, range: 0-4, IQR: 2) was significantly higher than after the initial episode (1, range: 0-4, IQR: 1; p = 0.005). Relapsing patients did not differ in their initial clinical and diagnostic features from 85 patients without relapse. Nevertheless, residual cognitive dysfunction after the initial episode (hazard ratio:13.8, 95% confidence interval [1.5; 129.5]; p = 0.022) and no administration of corticosteroids at the initial episode (hazard ratio: 4.8, 95% confidence interval [1.1; 21.1]; p = 0.036) were significantly associated with an increased risk of relapse.

DISCUSSION

Relapses may occur years after the initial encephalitis episode and are usually milder but cause additional disability. Corticosteroid treatment reduces the risk of future relapses, while patients with residual cognitive dysfunction after the initial episode have an increased relapse risk.

[Report of two cases of anti-LGI1 autoimmune encephalitis in Mexico]

Background: Anti-LGI1 encephalitis is characterized by a pattern of inflammation that predominantly affects the limbic system It is part of the autoimmune encephalitis that attack neuronal surface antigens. It is characterized by the triad of subacute dementia, faciobrachial dystonic crises, and hyponatremia, presenting an excellent response to immunotherapy. The aim of this article is to describe the clinical evolution and functional outcome at 6 months of two patients with anti-LGI1 encephalitis using clinical cases.

Clinical cases

Case 1: 62-year-old man with 8-week symptoms manifested by changes in mood, disorientation, and focal motor seizures. Case 2 A 72-year-old woman with a 5-month evolution of rapidly progressive dementia, hyponatremia and bitemporal hyperintensities on MRI. In both, due to clinical suspicion, acute dual immunotherapy with steroid and immunoglobulin was given with substantial improvement. Subsequently, the existence of anti-LGI1 antibodies in cerebrospinal fluid was confirmed. Although both patients received a dose of rituximab during their hospitalization, only the patient in the first case continued biannual doses of rituximab. The second patient was not initially considered to continue long-term immunomodulatory treatment and experienced a relapse.

Conclusions

These clinical vignettes present the reader with the classic characteristics of this disease. This can facilitate its recognition and timely initiation of treatment, improving the functional prognosis of patients.

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.

Fire acupuncture for anti-LGI1 antibody autoimmune encephalitis: a case report

Autoimmune encephalitis, a class of encephalitis, is clinically characterized by multifocal or diffuse brain injury, including aberrant mental behavior, convulsions, and near-event memory impairment. In this article, we describe a female patient with autoimmune encephalitis who tested positive for leucine-rich glioma inactivated 1 (LGI1) antibodies and had hippocampal inflammatory edema in the lesion area. During the first 3 months of her illness, the patient primarily experienced memory loss, the onset of rigid twitching in her extremities that lasted for 1 min while in remission, and incontinence. After gamma globulin administration, methylprednisolone shock, and other symptomatic therapies during hospitalization, the patient's psychiatric symptoms and seizures improved considerably; however, she did not fully recover her memory. After receiving fire acupuncture for 6 months, the patient's understanding, orientation, and calculation skills improved considerably. Her memory and mental state were also improved at the follow-up visit. In this case, the use of fire acupuncture for the treatment of autoimmune encephalitis resulted in favorable outcomes with important benefits for conditions affecting the central nervous system; however, more convincing data are required to support the effectiveness of this treatment method.

New Insights on DR and DQ Human Leukocyte Antigens in Anti-LGI1 Encephalitis

BACKGROUND AND OBJECTIVES

To explore the clinical characteristics and HLA associations of patients with anti-leucine-rich glioma-inactivated 1 encephalitis (LGI1E) from a large single center in Israel. Anti-LGI1E is the most commonly diagnosed antibody-associated encephalitic syndrome in adults. Recent studies of various populations reveal significant associations with specific HLA genes. We examined the clinical characteristics and HLA associations of a cohort of Israeli patients.

METHODS

Seventeen consecutive patients with anti-LGI1E diagnosed at Tel Aviv Medical Center between the years 2011 and 2018 were included. HLA typing was performed using next-generation sequencing at the tissue typing laboratory of Sheba Medical Center and compared with data from the Ezer Mizion Bone Marrow Donor Registry, containing over 1,000,000 samples.

RESULTS

Our cohort displayed a male predominance and median age at onset in the 7th decade, as previously reported. The most common presenting symptom was seizures. Notably, paroxysmal dizziness spells were significantly more common than previously reported (35%), whereas faciobrachial dystonic seizures were found only in 23%. HLA analysis revealed overrepresentation of DRB1*07:01 (OR: 3.18, CI: 20.9 p < 1.e-5) and DRB1*04:02 (OR: 3.8, CI: 20.1 p < 1.e-5), as well as of the DQ allele DQB1*02:02 (OR: 2.8, CI: 14.2 p < 0.0001) as previously reported. A novel overrepresentation observed among our patients was of the DQB1*03:02 allele (OR: 2.3, CI: 6.9 p < 0.008). In addition, we found DR-DQ associations, among patients with anti-LGI1E, that showed complete or near-complete linkage disequilibrium (LD). By applying LD analysis to an unprecedentedly large control cohort, we were able to show that although in the general population, DQB*03:02 is not fully associated with DRB1*04:02, in the patient population, both alleles are always coupled, suggesting the DRB1*04:02 association to be primary to disease predisposition. In silico predictions performed for the overrepresented DQ alleles reveal them to be strong binders of LGI1-derived peptides, similarly to overrepresented DR alleles. These predictions suggest a possible correlation between peptide binding sites of paired DR-DQ alleles.

DISCUSSION

Our cohort presents distinct immune characteristics with substantially higher overrepresentation of DRB1*04:02 and slightly lower overrepresentation of DQB1*07:01 compared with previous reports implying differences between different populations. DQ-DR interactions found in our cohort may shed additional light on the complex role of immunogenetics in the pathogenesis of anti-LGI1E, implying a possible relevance of certain DQ alleles and DR-DQ interactions.

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.

Cytokines/chemokines and immune checkpoint molecules in anti-leucine-rich glioma-inactivated 1 encephalitis

OBJECTIVE

We aimed to investigate levels of cytokines/chemokines and immune checkpoint molecules in patients with anti-leucine-rich glioma-inactivated 1 (LGI1) encephalitis.

METHODS

The study recruited 12 patients with anti-LGI1 encephalitis and six non-inflammatory controls from the Qilu Hospital of Shandong University treated between January 2019 and December 2020. Serum levels of 30 cytokines/chemokines and 10 checkpoint molecules were measured in participants of both the groups.

RESULTS

In contrast to those in the control group, 24 cytokines/chemokines and 5 immune checkpoint molecules were differentially expressed in patients with anti-LGI1 encephalitis, with 14 cytokines being upregulated and 10 being downregulated. There were 1033 enriched biological processes and 61 enriched Kyoto Encyclopedia of Genes and Genomes signaling pathways.

CONCLUSION

A wide range of cytokines/chemokines and immune checkpoint molecules are implicated in immune regulation in anti-LGI1 encephalitis, indicating that they may serve as important targets in the development and treatment of the disease.

Encephalitis in adults in the Auckland and Northland regions of New Zealand, 2009 to 2018

We conducted a retrospective study to determine the incidence and frequency of different subtypes of encephalitis in patients aged 15 and older in the Auckland and Northland regions of New Zealand between 2009 and 2018. Residents in Auckland and Northland presenting with encephalitis between 2009 and 2018 were identified from three overlapping databases: positive cerebrospinal fluid (CSF) viral polymerase chain reaction (PCR) tests, CSF neuronal antibody requests, and CSF neuronal antibody tests sent overseas. A diagnosis of autoimmune encephalitis required fulfilment of diagnostic criteria published by Graus and colleagues (2016). One hundred and thirty-six (69, 50.7% female) patients met study inclusion criteria. The median age was 59 (range 15-92). The annual incidence was 1.10 cases per 100,000 person-years. Of these 136 patients, 56 (41.2%) had an infectious aetiology, with varicella zoster (26, 46.4%) and herpes simplex (23, 41.1%) being the most common agents. Autoimmune encephalitis was diagnosed in 32 patients (23.5%). LGI-1 antibody was the most commonly identified neuronal autoantibody (10 patients, 13.2%). Forty-eight patients (35.3%) had encephalitis of unknown cause. In-hospital mortality for infectious encephalitis was 12.5%, autoimmune encephalitis 6.3%, and encephalitis of unknown cause 10.4%. Compared to a previous analysis of encephalitis in adults in Auckland, the incidence of encephalitis and autoimmune encephalitis had increased. The proportion of patients with an unknown cause for encephalitis had decreased.

Prognostic significance and extra-hypothalamus dysfunction of hyponatremia in anti-leucine-rich glioma-inactivated protein 1 encephalitis

This study aimed to investigate prognostic significance and brain metabolic mechanism of hyponatremia in anti-leucine-rich glioma-inactivated protein 1 (LGI1) encephalitis. After adjusting for confounders, patients with moderate and severe hyponatremia had significantly increased risk of poor functional outcome and sequelae of seizures. In addition, serum sodium was negatively correlated with normalized ratio of the standardized uptake value of medial temporal lobe (MTL), basal ganglia (BG), and hypothalamus on positron emission tomography (PET) and which was further validated using voxel-wise analysis, suggesting an extra-hypothalamus (BG and MTL) localization for hyponatremia.

Review and meta-analysis of neuropsychological findings in autoimmune limbic encephalitis with autoantibodies against LGI1, CASPR2, and GAD65 and their response to immunotherapy

OBJECTIVES

It is assumed that autoimmune limbic encephalitis (ALE) demonstrates distinct neuropsychological manifestations with differential responses to immunotherapy according to which associated autoantibody (AAB), if any, is identified. Towards investigating whether this is the case, this study aims to summarize respective findings from the primary literature on ALE with AABs binding to cell surface neural antigens and ALE with AABs against intracellular neural antigens.

METHODS

We chose ALE with AABs against leucine-rich, glioma inactivated protein 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) as the most frequent cell surface membrane antigens, and ALE with AABs to Embryonic Lethal, Abnormal Vision, Like 1 (ELAVL) proteins (anti-Hu) and glutamic acid decarboxylase 65 (GAD65) as the most frequent intracellular neural antigens. The PubMed and Scopus databases were searched on March 1st, 2021 for neuropsychological test and -screening data from patients with ALE of these AAB-types. Findings were reviewed according to AAB-type and immunotherapy status and are presented in a review section and are further statistically evaluated and presented in a meta-analysis section in this publication.

RESULTS

Of the 1304 initial hits, 32 studies on ALE with AABs against LGI1, CASPR2, and GAD65 reporting cognitive screening data could be included in a review. In ALE with AABs against LGI1, CASPR2 and GAD65, memory deficits are the most frequently reported deficits. However, deficits in attention and executive functions including working memory, fluency, and psychological function have also been reported. This review shows that ALE patients with AABs against both LGI1 and CASPR2 show higher percentages of neuropsychological deficits compared to ALE patients with AABs against GAD65 before and after initiation of immunotherapy. However, the methodologies used in these studies were heterogenous, and longitudinal studies were not comparable. Moreover, 21 studies including ALE patients with AABs against LGI1 and GAD65 were also suitable for meta-analysis. No suitable study on ALE with AABs against ELAVL proteins could be identified. Meta-Analyses could be executed for cognitive screening data and only partially, due to the small number of studies. However, in statistical analysis no consistent effect of AAB or immunotherapy on performance in cognitive screening tests could be found.

CONCLUSION

Currently, there is no definite evidence supporting the notion that different AAB-types of ALE exhibit distinct neuropsychological manifestations and respond differently to immunotherapy. Overall, we could not identify evidence for any effect of immunotherapy on cognition in ALE. More systematic, in-depth and longitudinal neuropsychological assessments of patients with different AAB-types of ALE are required in the future to investigate these aspects.

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.

Neuropsychological and Structural Neuroimaging Outcomes in LGI1-Limbic Encephalitis: A Case Study

OBJECTIVE

Anti-leucine-rich glioma-inactivated 1 limbic encephalitis (LGI1-LE) is a rare autoimmune condition that affects the structural integrity and functioning of the brain's limbic system. Little is known about its impact on long-term neuropsychological functioning and the structural integrity of the medial temporal lobe. Here we examined the long-term neuropsychological and neuroanatomical outcomes of a 68-year-old male who acquired LGI1-LE.

METHODS

Our case patient underwent standardized neuropsychological testing at two time points. Volumetric analyses of T1-weighted images were undertaken at four separate time points and qualitatively compared with a group of age-matched healthy controls.

RESULTS

At the time of initial assessment, our case study exhibited focal impairments in verbal and visual episodic memory and these impairments continued to persist after undergoing a course of immunotherapy. Furthermore, in reference to an age-matched healthy control group, over the course of 11 months, volumetric brain imaging analyses revealed that areas of the medial temporal lobe including specific hippocampal subfields (e.g., CA1 and dentate gyrus) underwent a subacute period of volumetric enlargement followed by a chronic period of volumetric reduction in the same regions.

CONCLUSIONS

In patients with persisting neurocognitive deficits, LGI1-LE may produce chronic volume loss in specific areas of the medial temporal lobe; however, this appears to follow a subacute period of volume enlargement possibly driven by neuro-inflammatory processes.

Confusion and Hallucination in a Geriatric Patient. Pitfalls of a Rare Differential: Case Report of an Anti-LGI1-Encephalitis

Background

Confusion and hallucinations in geriatric patients are frequent symptoms and typically associated with delirium, late-life psychosis or dementia syndromes. A far rarer but well-established differential in patients with rapid cognitive deterioration, acute psychosis, abnormal movements and seizures is autoimmune encephalitis. Exemplified by our case we highlight clinical and economic problems arising in management of geriatric patients with cognitive decline and psychotic symptoms.

Case Presentation

A 77-year-old female caucasian patient with an unremarkable medical history was hospitalized after a fall in association with diarrhea and hyponatremia. Upon adequate therapy, disorientation and troubled short-term memory persisted. Within a week the patient developed visual hallucinations. Basic blood and urine samples and imaging (cranial computed tomography and magnetic resonance imaging) were unremarkable. With progressive cognitive decline, amnestic impairment, word finding difficulty and general apathy, psychiatric and neurologic expertise was introduced. Advanced diagnostics did not resolve a final diagnosis; an electroencephalogram showed unspecific generalized slowing. Extended clinical observation revealed visual hallucinations and faciobrachial dystonic seizures. A treatment with anticonvulsants was initiated. Cerebrospinal fluid ultimately tested positive for voltage-gated potassium channel LGl1 (leucine-rich-inactivated-1) antibodies confirming diagnosis of autoimmune anti-LGI1 encephalitis. Immediate immunotherapy (high-dose glucocorticoids and administration of intravenous immunoglobulin G) led to a rapid improvement of the patient’s condition. After immunotherapy was tapered, the patient had one relapse and completely recovered with reintroduction of glucocorticoids and initiation of therapy with rituximab.

Conclusion

Rapidly progressive dementia in geriatric patients demands a structured and multidisciplinary diagnostic approach. Accurate management and financially supportable care is a major issue in rare diseases such as anti-LGI1-encephalitis. Education and awareness about autoimmune encephalitis of all physicians treating a geriatric population is important in order to involve expertise and establish treatment within reasonable time.

Clinical features and outcomes of leucine-rich glioma-inactivated protein 1 and contactin protein-like 2 antibody-associated autoimmune encephalitis in a Chinese cohort

The present study aimed to investigate the clinical manifestations, epidemiological characteristics, and outcomes of Chinese patients with voltage-gated potassium channel complex (VGKC) antibody-associated encephalitis. Patients diagnosed with VGKC antibody-associated encephalitis at our institution between January 2016 and December 2020 were included in this study. We retrospectively evaluated their clinical features, auxiliary examination results, treatments details, long-term outcomes, and risk factors for poor outcome. Of the 91 included patients, 61 (67.78%) were men and 30 (32.97%) were women. The most common clinical symptoms were seizures (n = 63, 69.23%), memory deficits (n = 62, 68.13%), mental behavioral disorders (n = 29, 31.87%), and hyponatremia (n = 57, 62.64%). Although patients with anti- leucine-rich glioma-inactivated 1 (LGI1) (n = 76) and anti- contactin-associated protein-like 2 (CASPR2) encephalitis (n = 15) had similar clinical manifestations, the former were more diverse. In total, 86 (94.51%) patients were treated with immunotherapy. Over a median follow-up period of 25 months, there were no mortalities and 14 (15.38%) patients experienced a relapse. Univariate analysis indicated differences in sex, modified Rankin Scale scores at onset, movement disorders, central hypoventilation, and intensive care unit occupancy between the good- and poor- outcome groups. Patients with anti-LGI1 and anti-CASPR2 encephalitis showed similar clinical manifestations while presenting delineating characteristics. Those with VGKC antibody-associated diseases generally responded well to immunotherapy and demonstrated favorable clinical outcomes. Several factors affected the prognosis, and a long-term follow-up examination is necessary.

Clinical Features, Immunotherapy, and Outcomes of Anti-Leucine-Rich Glioma-Inactivated-1 Encephalitis

OBJECTIVE

The investigators aimed to explore the clinical characteristics, immunotherapy, and outcomes of patients with antileucine-rich glioma-inactivated-1 (anti-LGI1) encephalitis.

METHODS

Data on participants' clinical characteristics, laboratory findings, radiological and electroencephalogram (EEG) features, treatment, and outcomes from January 2012 to December 2016 were collected. Statistical analysis was conducted to assess the factors associated with patient functional outcome. Forty-three patients were enrolled in the study, with a predominance of males (65.1%). The median age at onset was 57 years (interquartile range [IQR]: 44.0-65.0). The median time from onset to diagnosis was 60 days (IQR: 37.0-127.0).

RESULTS

The main clinical manifestations included epilepsy (100%), faciobrachial dystonic seizures (FBDS; 44.2%), cognitive dysfunction (95.3%), neuropsychiatric disturbances (76.7%), sleep disorders (58.1%), and disturbance of consciousness (48.8%). Twenty-two patients (51.2%) had hyponatremia, 31 (72.1%) had abnormal EEG results, and 30 (69.8%) had abnormal brain MRI scans, mainly involving the hippocampus (76.7%) or temporal lobe (40%). Twenty of 34 patients (58.8%) in a follow-up MRI examination exhibited hippocampal atrophy. Twenty-five patients (58.2%) were administered corticosteroids and intravenous immunoglobulin, whereas 17 patients were treated only with corticosteroids. Forty-one patients (95.3%) had favorable outcomes after a median of 21.5 months (IQR: 7-43) of follow-up. Serum sodium level was a factor associated with a disabled status (odds ratio=0.81, 95% CI=0.66, 0.98, p=0.03). Anti-LGI1 encephalitis patients were characterized by seizures, FBDS, cognitive deficits, neuropsychiatric disturbances, and hyponatremia.

CONCLUSIONS

Most patients with anti-LGI1 encephalitis are nonparaneoplastic, have low recurrence rates, and have favorable prognostic outcomes. Rapid evaluation, prompt immunotherapy, and long-term follow-up are essential in the care of anti-LGI1 encephalitis patients.

HLA-DRB1*03:01 is associated with female sex and younger age of anti-LGI1 encephalitis

OBJECTIVE

To investigate the association between human leukocyte antigen (HLA) genotype and clinical characteristics of anti-LGI1 encephalitis.

METHODS

HLA genotyping was performed in 34 patients with anti-LGI1 encephalitis admitted to West China Hospital between April 2014 and May 2021, as well as in 305 healthy controls. The on-line tool NetMHCIIpan 4.0 and AutoDock Vina software were used to predict binding between LGI1 peptide and HLA Class II molecules.

RESULTS

Risk of anti-LGI1 encephalitis was strongly associated with the DRB1*03:01 allele (OR 4.31, 95% CI 1.96-9.25, Pc = 2.75×10^-4 ) and the DRB1*03:01-DQB1*02:01 haplotype (OR 4.45, 95% CI 2.02-9.59, Pc = 2.94×10^-4 ). Compared to carriers of the DRB1*07:01 allele, those with the DRB1*03:01 allele were more likely to be female (93.3% vs 33.3%; P = 0.004) and to be younger (median age, 38 vs 65 years; P < 0.001). DRB1*03:01 carriers showed stronger response to immunotherapy than carriers of the DRB1*07:01 allele, based on median score decrease on the modified Rankin scale [2 (interquartile range, 1-2) vs. 1 (interquartile range, 0-1); P = 0.03] at 4 weeks after immunotherapy. Prediction and docking algorithms suggested that the LGI1 peptide can bind to the DRB1*03:01 molecule strongly.

CONCLUSIONS

The strong association between anti-LGI1 encephalitis and certain HLA class II alleles supports a primary autoimmune origin for the disease. Carriers of the DRB1*03:01 allele in Chinese patients with anti-LGI1 encephalitis are more likely to be female, to suffer earlier disease onset and to respond better to immunotherapy.

Thyroid Function and Low Free Triiodothyronine in Chinese Patients With Autoimmune Encephalitis

Background and Objectives

Low free triiodothyronine (FT3) is usually associated with worse functional outcome in critical illness; however, the information on thyroid dysfunction and autoimmune encephalitis (AE) is limited. This study aims to evaluate the clinical prognostic value of thyroid function and low-T3 syndrome in patients with multiple subtypes of AE.

Methods

In this retrospective study, we identified the hospital records of 319 candidate patients with AE admitted between January 2016 and December 2020. We then extracted the clinical features and outcomes. Modified Rankin scale (mRS) scores were used to evaluate the patients’ neurological function. The serum levels of FT3, free thyroxine (FT4), and thyroid-stimulating hormone (TSH) were measured upon admission. Normal thyroid stimulating hormone level with FT3 below the lower limit of the reference interval (2.63 nmol/L) was defined as low-T3 syndrome.

Results

A total of 237 AE cases remained after screening. Among these, 57.81% (137/237) were men and the average age at onset was 41 y (interquartile range, 12–61 y). We found that 83.54% (198/237) of the patients had a good prognosis, and 16.46% (39/237) had a poor prognosis. Abnormal thyroid function was observed in 30.80% of these patients, with a relatively greater prevalence in the group with a poor prognosis (p < 0.001). The serum FT3 levels in the poor-prognosis group were significantly lower than those in the good-prognosis group (p < 0.001). Low-T3 syndrome occurred in 15.19% of AE cases and was more frequent in patients with poor prognosis (p < 0.001).

Conclusions

Abnormal thyroid function in AE is frequent, and serum FT3 levels in patients with poor prognosis are significantly lower than in those with good prognosis. Low-T3 syndrome could be a potential candidate for predicting the prognosis of AE following future research.

Contemporary advances in antibody-mediated encephalitis: anti-LGI1 and anti-Caspr2 antibody (Ab)-mediated encephalitides

Encephalitides with antibodies directed against leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (Caspr2) represent two increasingly well characterised forms of autoimmune encephalitis. Both share overlapping and distinct clinical features, are mediated by autoantibodies directed against differing proteins complexed with voltage-gated potassium channels, with unique genetic predisposition identified to date. Herein we summarise disease mechanisms, clinical features, treatment considerations, prognostic factors and clinical outcomes regarding these disorders.

Positive LGI1 Antibodies in CSF and Relapse Relate to Worse Outcome in Anti-LGI1 Encephalitis

Objective

This single-center study was conducted in a cohort of patients with anti-LGI1 encephalitis to investigate the factors related to their functional recovery.

Methods

We retrospectively collected the clinical information of patients admitted to Xuanwu Hospital from January 2014 until December 2019, and followed up for at least 12 months.

Results

A total of 67 patients were included, and 57 completed the 12-month follow-up. Most of the patients (55/57, 96.5%) achieved functional improvement after immunotherapy, and 26 (45.6%) became symptom-free. Compared to patients with complete recovery, patients with partial or no recovery had significantly higher incidences of consciousness disorders (25.8% vs. 0%, P<0.05) and positive LGI1 antibodies in cerebrospinal fluid (CSF) (71.0% vs. 46.2%, P<0.05). These patients also had a lower Barthel Index both upon admission and at discharge, as well as a higher incidence of relapse (25.8% vs. 3.8%; P<0.05 each). Univariate logistic regression showed that positive LGI1 antibodies in CSF and relapse were associated with incomplete recovery at 1-year follow-up (both P<0.05), but only relapse remained statistically significant after multivariate logistic regression (P=0.034).

Conclusion

Patients with LGI1 antibodies in CSF and those who relapsed were more likely to experience worse outcome. Early recognition of these patients, combined with more aggressive immunotherapy may result in better recovery.

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.

Long-term seizure outcomes in patients with anti-Leucine-rich glioma-inactivated 1 encephalitis

BACKGROUND

This study aimed to investigate the semiology of seizure disorders, including electroencephalographic characteristics, and seizure outcomes in participants with anti-leucine-rich glioma-inactivated 1 (LGI-1) encephalitis.

METHODS

Seventy participants who presented with seizures during the acute phase of anti-LGI-1 encephalitis at Peking Union Medical College Hospital from May 2013 to July 2020 were reviewed. All participants underwent follow-up for longer than 2 years.

RESULTS

At the time of presentation, 48 (68.6%) participants had generalized seizures and 57 (81.4%) had focal seizures. The most common focal motor seizures were faciobrachial dystonic seizures (FDS). The main manifestations of focal nonmotor seizures were dyscognitive features, goosebumps, and disorders of sensation. All participants received immunomodulatory therapy. Thirty-five (50%) participants were seizure free after 1 year of follow-up, and 48 (68.6%) participants were seizure free over a follow-up of 2 years. Participants with seizures continued longer than 1 year were older than participants whose seizure duration was shorter than 1 year (P = 0.021). However, after an extended follow-up period, the difference between the incidences of seizures based on age was not significant. The frequency of focal motor seizures was higher in participants who became seizure free within 1 year, compared to participants who had seizures for longer than 1 year (75% vs 54.3%, respectively; P = 0.015). Participants with seizures continued over 2 years tended to have focal nonmotor seizures, and tended to show an elevated incidence of abnormal EEG results. Participants receiving early corticosteroid and longer duration immunosuppressant treatments, tended to have a lower risk of persistent seizures and better seizure outcomes, with no statistical significance.

CONCLUSIONS

Most participants obtained remission from seizures after immunomodulatory therapy. The seizure manifestation of anti-LGI1 encephalitis is diverse and variable. The type of focal seizures may affect the outcome of participants with seizures. Older age could lead to longer duration of the seizure disorder, but did not affect the rate of seizures over the long term. Early and prolonged administration of immunomodulatory therapy may be useful for shortening the time to becoming seizure free.

Characteristics and Prognosis of Autoimmune Encephalitis in the East of China: A Multi-Center Study

Objective: This study aimed to investigate epidemiological characteristics, clinical manifestations, and long-term outcomes of patients with autoimmune encephalitis (AE) in the east of China.

Methods: From January 2015 to December 2019, 226 potential AE patients were recruited from five clinical centers, and a total of 185 patients who met the diagnostic criteria were included in the study. We retrospectively reviewed clinical features, auxiliary examinations, details of treatments, and outcomes of AE, and identified risk factors of poor prognosis. Modified Rankin Scale scores were used to evaluate neurological function, and scores of 3–6 indicated a poor-prognosis.

Results: Patients with five main subtypes of AE were enrolled in the study, as follows: anti-NMDAR (79), anti-LGI1 (55), anti-CASPR2 (30), anti-GABABR (16), and anti-AMPAR (5). Among 185 patients, 58.38% (108/185) were male and 41.62% (77/185) were female. The median age at disease onset was 41 years (interquartile range, 17–62). The most common clinical manifestations of AE were seizures (146, 78.92%) and memory deficit (123, 66.49%). A total of 95 (51.35%) patients had abnormal brain magnetic resonance imaging results. Electroencephalographic findings were abnormal in 131 (70.81%) patients, and 168 (90.81%) and 26 (14.05%) patients were treated with first- and second-line immunotherapies, respectively. All surviving patients were followed-up for at least 1 year (range 12–36 months). Good clinical outcomes were achieved in 117 (63.24%), while 68 (36.76%) patients had a poor prognosis. Further, 33 (17.84%) patients relapsed and 10 (5.41%) died within 1 year post-discharge. Older patients tended to have a poorer prognosis, and the occurrence of mental behavioral disorders, movement disorders, disturbance of consciousness, central hypoventilation, and tumors were overrepresented in the poor-prognosis group.

Conclusions: AE is a treatable disease, and most patients have a good prognosis. There are differences in the clinical manifestations of patients with different AE subtypes. Some with AE will relapse, and long-term follow-up is of great significance for further research.