Anti-leucine-rich Glioma-inactivated 1 Protein-antibody Positive Encephalitis with Extensive Unilateral Cerebral Cortex and White Matter Lesions.

Encephalitis caused by antibodies targeting the leucine-rich glioma-inactivated 1 protein receptor, which belongs to the anti-voltage-gated potassium channel receptor complex, is characterized by hyponatremia, progressive cognitive impairment, seizures, and psychiatric disorders. The patient initially presented with faciobrachial dystonic seizures and subsequently developed encephalopathy. Brain magnetic resonance imaging revealed atypical unilateral hyperintense signals in the cerebral cortex and white matter. Intravenous corticosteroid pulse therapy effectively improved faciobrachial dystonic seizures and brain lesions.

Relapsing polychondritis presenting with sero-negative limbic encephalitis.

The presented case highlights a rare instance of relapsing polychondritis (RP) manifesting as seronegative limbic encephalitis, an uncommon neurological complication. A 70-year-old female patient with a history of RP-related inflammation, along with neuropsychiatric symptoms, was diagnosed through multidisciplinary collaboration. Swift administration of steroid therapy, followed by azathioprine, led to remarkable physical and cognitive recovery. This case emphasises the importance of a multidisciplinary approach in diagnosing and treating complex autoimmune disorders with neurological manifestations.

[Thymoma-associated generalized myasthenia gravis complicated with anti-VGKC complex antibody-associated limbic encephalitis: a case report].

We present a case of a 54-year-old woman. She was attending our department for thymoma-associated generalized myasthenia gravis. While she was treated with intravenous immunoglobulins for the exacerbation of myasthenic symptoms, she suddenly lost her consciousness for the first time and continued to have mild disorientation along with anterograde and retrograde amnesia afterwards. The symptoms improved after steroid pulse therapy. After searching for autoantibodies, she was diagnosed with anti-VGKC complex antibody-associated limbic encephalitis. As one-third of cases are complicated by thymoma, anti-VGKC complex antibody-positive limbic encephalitis has the aspect of a paraneoplastic neurological syndrome. In this case, masses suspected to be a recurrence of thymoma were found. In cases of thymoma, involvement of anti-VGKC complex antibodies should be considered when central nervous system symptoms appear, and when anti-VGKC complex antibodies are positive, recurrence or exacerbation of thymoma should be considered.

Relation of Motor Impairments to Neuropathologic Changes of Limbic-Predominant Age-Related TDP-43 Encephalopathy in Older Adults.

BACKGROUND AND OBJECTIVES: Limbic-predominant age-related transactive response DNA-binding protein 43 (TDP-43) encephalopathy neuropathologic change (LATE-NC) is common and is a major contributor to cognitive decline and Alzheimer dementia in older adults. The objective of the current study was to examine whether LATE-NC was also associated with declining motor function in older adults. METHODS: Participants were from 2 longitudinal clinical pathologic studies of aging who did not have dementia at the time of enrollment. Postmortem pathologic examination included immunohistochemical staining for TDP-43 in 8 brain regions, which was summarized as a dichotomous variable indicating advanced LATE-NC stages at which TDP-43 pathology had accumulated in the hippocampus, entorhinal, or neocortical regions. Annual motor testing included maximal inspiratory and expiratory pressures (summarized as respiratory muscle strength), grip and pinch strength (summarized as hand strength), finger tapping speed and the Purdue Pegboard Test (summarized as hand dexterity), and walking 8 feet and turning 360° (summarized as gait function). The severity of parkinsonism was also assessed and summarized as a global parkinsonism score. Global cognition was a summary of standardized scores of 19 neuropsychological tests. We used linear mixed-effect models to examine the associations of LATE-NC with longitudinal changes of motor decline and used multivariate random coefficient models to simultaneously examine the associations of LATE-NC with cognitive and motor decline. RESULTS: Among 1,483 participants (mean age at death 90.1 [SD = 6.4] years, 70% women, mean follow-up 7.4 [SD = 3.8] years), LATE-NC was present in 34.0% (n = 504). In separate linear mixed-effect models controlling for demographics and other brain pathologies, LATE-NC was associated with faster decline in respiratory muscle strength (estimate = -0.857, SE = 0.322, p = 0.008) and hand strength (estimate = -0.005, SE = 0.002, p = 0.005) but was not related to hand dexterity, gait function, or parkinsonism. In multivariate random coefficient models including respiratory muscle strength, hand strength, and global cognition as the outcomes, LATE-NC remained associated with a faster respiratory muscle strength decline rate (estimate = -0.021, SE = 0.009, p = 0.023), but the association with hand strength was no longer significant (estimate = -0.002, SE = 0.003, p = 0.390). DISCUSSION: Motor impairment, specifically respiratory muscle weakness, may be an unrecognized comorbidity of LATE-NC that highlights the potential association of TDP-43 proteinopathy with noncognitive phenotypes in aging adults.

Cancer detection after a 9-year course of Lambert-Eaton myasthenic syndrome complicated by anti-Hu associated limbic encephalitis.

Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune neuromuscular junction disorder, paraneoplastic in 55% of cases and commonly associated with small-cell lung cancer (SCLC). We report the case of a 61-year-old man presented who with a 3-month history of lower limb proximal weakness, progressing to upper limbs, associated with dysphagia, xerostomia and erectile dysfunction. Electrodiagnostic studies and anti voltage-gated calcium channel (VGCC) antibodies (Abs) detection confirmed LEMS diagnosis. Contrast-enhanced thorax computed tomography (CT) scan and subsequently [18F]-fluorodeoxyglucose (FDG) positron emission tomography (PET) showed no malignancy. Two years after the onset of LEMS, he was diagnosed with anti-Hu limbic encephalitis (LE). FDG-PET/CT scan remained negative for the following seven years. Nine years after LEMS onset, a hypermetabolic lesion of the left lung hilus was detected. This is a case of a paraneoplastic LEMS where the interval between the onset of neurological disease and tumour detection was as long as nine years.

Limbic encephalitis secondary to neuro-Behcet disease: an uncommon presentation. / Encefalitis límbica secundaria a neuro-Behçet: una presentación insólita.

INTRODUCTION: Limbic encephalitis (LE) can have a wide range of etiologies, most frequently infectious (especially viral) or autoimmune. Behcet's disease (BD) can present with heterogeneous neurological manifestations. However, LE is not considered a typical presentation of neuro-Behcet's disease (NBD). CASE REPORT: A 40-years-old male presented with new-onset subacute headaches, memory problems and apathy. A review of systems revealed an unrecorded past history of recurrent oral sores for years, recent malaise and fever, as well as an episode of bilateral panuveitis four months before presentation. His general and neurologic examination revealed slight fever, an isolated oral aphtha, anterograde amnesia and signs of bilateral retinal vasculitis. Brain magnetic resonance imaging displayed a pattern of limbic meningoencephalitis, and his cerebrospinal fluid showed mononuclear inflammation. The patient met BD diagnostic criteria. Considering LE is a very rare presentation of NBD, alternative etiologies were thoroughly assessed and excluded, including infectious, autoimmune and paraneoplastic encephalitis. Therefore, he was diagnosed with NBD, and he recovered well after immunosuppression. DISCUSSION: Only two cases of NBD presenting with LE have been previously reported. We report a third case of this rare presentation and compare it with the previous two. We aim to highlight this association and contribute to enlarge the rich clinical spectrum of NBD.

TITLE: Encefalitis límbica secundaria a neuro-Behçet: una presentación insólita.Introducción. La encefalitis límbica (EL) puede tener un amplio abanico de etiologías, más frecuentemente la infecciosa (sobre todo viral) o autoinmune. La enfermedad de Behçet (EB) puede presentarse con manifestaciones neurológicas heterogéneas. Sin embargo, la EL no se considera una presentación típica del neuro-Behçet (NB). Caso clínico. Varón de 40 años que consultó por cefalea de novo subaguda, problemas de memoria y apatía. La anamnesis por sistemas reveló una historia no conocida previamente de aftas orales recurrentes durante años, fiebre y afectación general reciente, así como un episodio de panuveítis bilateral cuatro meses antes de la presentación. Su exploración general y neurológica reveló febrícula, una afta oral aislada, amnesia anterógrada y signos de vasculitis retiniana bilateral. La resonancia magnética mostró un patrón de afectación de meningoencefalitis límbica y su líquido cefalorraquídeo presentaba inflamación mononuclear. El paciente cumplía los criterios diagnósticos de la EB. Considerando que la EL es una presentación muy rara del NB, se buscaron exhaustivamente y se excluyeron otras etiologías alternativas, incluyendo las encefalitis infecciosas, autoinmunes y paraneoplásicas. En consecuencia, el paciente se diagnosticó de NB y mostró una buena recuperación con tratamiento inmunosupresor. Discusión. Sólo dos casos de NB con presentación en forma de EL se han publicado previamente. Comunicamos el tercer caso de esta rara manifestación clínica de la EB y lo comparamos con los dos anteriores, con el objetivo de destacar dicha asociación y contribuir a expandir el rico espectro clínico del NB.

Rare Association of Autoimmune Limbic Encephalitis and Stiff Person Syndrome.

Antibodies to Glutamic Acid Decarboxylase (GAD) have been implicated in the pathogenesis of both autoimmune Limbic Encephalitis (LE) and Stiff Person Syndrome (SPS). However, their association is quite rare. We present a case of a 48-year-old Caucasian female who presented with symptoms of recurrent severe headaches, behavioral and cognitive dysfunction, and an episode of seizure. She was found to have high titers of anti-GAD65 antibodies in both cerebrospinal fluid and serum. She was diagnosed with LE and SPS, and was started on immunosuppressive therapy with steroids and intravenous immunoglobulins (IVIG). The patient responded well to treatment with improvement in her symptoms.

Anti-metabotropic glutamate receptor 5 encephalitis: Five case reports and literature review.

OBJECTIVE: To describe the clinical and radiological characteristics of anti-metabotropic glutamate receptor 5 (mGluR5) encephalitis. METHODS: We reviewed the clinical data of five patients with anti-mGluR5 encephalitis, and performed a literature review. RESULTS: The five cases included a 52-year-old man who developed a biphasic course of anti-mGluR5 encephalitis after herpes simplex encephalitis, a 22-year-old woman who showed bilateral basal ganglia lesions on brain magnetic resonance imaging (MRI), and a 36-year-old man with mixed aphasia and generalized tonic-clonic seizures, a 51-year-old man presented with personality changes, hallucinations, delusions, sleeping disorders and a 58-year-old man with short-term memory deficits and absence seizures.. There are 16 reported cases of anti-mGluR5 encephalitis worldwide. Of all 21 patients, with a median onset age of 35 years old, the main neurological symptoms were cognitive impairment (85.7%, 18/21), psychiatric or behavior problems (76.2%, 16/21), seizures (57.1%, 12/21), sleeping disorders (52.4%, 11/21), different degrees of decreased consciousness (42.9%, 9/21), and movement disorders (23.8%, 5/21). Brain MRI was normal in 11 of 21 patients. Lesions of the limbic lobes were presented in 5 patients, while involvement of other extralimbic regions was also reported. Seven of 21 (33.3%) cases were combined with tumors. Elevated white blood cell counts or specific oligoclonal IgG bands in the cerebrospinal fluid were found in 18 of 21 patients, with marked improvements observed after immunotherapy. DISCUSSION: Patients with anti-mGluR5 encephalitis typically present with diffuse, rather than purely limbic, encephalitis. Anti-mGluR5 encephalitis can be triggered by herpes simplex encephalitis. The risk of a combined tumor may be reduced in anti-mGluR5 encephalitis patients.

A feline model of spontaneously occurring autoimmune limbic encephalitis.

Autoimmune encephalitis (AE) is an important cause of encephalitis in humans and occurs at a similar rate to infectious encephalitis. It is frequently associated with antibodies against the extracellular domain of neuronal proteins. Among human AE, that with antibodies against leucine-rich glioma-inactivated 1 (LGI1) is one of the most prevalent forms, and was recently described in cats with limbic encephalitis (LE). In this study, we describe a large cohort (n = 32) of cats with AE, tested positive for voltage gated potassium channel (VGKC)-antibodies, of which 26 (81%) harboured LGI1-antibodies. We delineate their clinical and paraclinical features as well as long-term outcomes up to 5 years. Similar to human cases, most cats with LGI1-antibodies had a history of focal seizures (83%), clustering in the majority (88%), with interictal behavioural changes (73%). Among feline AE patients, there was no seizure type or other clinical characteristic that could distinguish LGI1-antibody positive from negative cats, unlike the pathognomic faciobrachial dystonic seizures seen in humans. Although six cats were euthanased in the first year for epilepsy-associated reasons, those attaining at least 1-year survival had good seizure control and quality of life with appropriate veterinary care and medication. Acute-phase immunotherapy (prednisolone) was given to the most severely unwell cases and its effect is retrospectively evaluated in 10 cats. Our data show LGI1-antibodies are an important cause of feline encephalitis, sharing many features with human AE. Further research should examine optimal therapeutic management strategies and the cause of LE in seronegative cats, building on paradigms established in the counterpart human disease.

18FDG PET/CT Tumoral and Neurologic Therapeutic Response in a Case of Anti-GABABR Paraneoplastic Limbic Encephalitis.

ABSTRACT: A 70-year-old man with a history of small cell lung carcinoma 2 years earlier was addressed for the suspicion of a paraneoplastic limbic encephalitis. Brain 18FDG PET/CT revealed a bilateral amygdalian and hippocampal hypermetabolism, confirming a limbic encephalitis, and concurrent whole-body 18FDG PET/CT showed a small cell lung carcinoma plurifocal metastatic recurrence, consistent with a paraneoplastic limbic encephalitis. 18FDG PET/CT follow-up under chemotherapy revealed an almost complete normalization of brain metabolism and a partial metabolic response of the metastatic recurrence, consistent with the good clinical neurological evolution of the patient. This case highlights the clinical-metabolic imaging correlation in paraneoplastic limbic encephalitis.

Antibody Properties Associate with Clinical Phenotype in LGI1 Encephalitis.

Autoimmune encephalitis (AE) associated with autoantibodies against leucine-rich glioma-inactivated protein-1 (LGI1) can present with faciobrachial dystonic seizures (FBDS) and/or limbic encephalitis (LE). The reasons for this heterogeneity in phenotypes are unclear. We performed autoantibody (abs) characterization per patient, two patients suffering from LE and two from FBDS, using isolated antibodies specified with single amino acid epitope mapping. Electrophysiological slice recordings were conducted alongside spine density measurements, postsynaptic Alpha-amino-3-hydoxy-5-methyl-4-isoaxole-proprionate-receptors (AMPA-R) and N-methyl-D-aspartate-receptors receptor (NMDA-R) cluster counting. These results were correlated with the symptoms of each patient. While LGI1 abs from LE patients mainly interacted with the Leucine-rich repeat section of LGI1, abs from both FBDS patients also recognized the Epitempin section as well. Six-hour incubation of mouse hippocampal slices with LE patients autoantibodies but not from the FBDS patients resulted in a significant decline in long-term potentiation (p = 0.0015) or short-term plasticity at CA3-CA1 neurons and in decreased hippocampal synaptic density. Cluster differentiation showed no decrease in postsynaptic AMPA-R and NMDA-R. LGI1 autoantibodies selected by phenotype show an almost distinct epitope pattern, elicit disparate functional effects on hippocampal neurons, and cause divergent effects on spine density. This data illuminates potential pathomechanisms for disease heterogeneity in LGI1 AE.

Temporal lobe epilepsy with GAD antibodies: neurons killed by T cells not by complement membrane attack complex.

Temporal lobe epilepsy (TLE) is one of the syndromes linked to antibodies against glutamic acid decarboxylase (GAD). It has been questioned whether 'limbic encephalitis with GAD antibodies' is a meaningful diagnostic entity. The immunopathogenesis of GAD-TLE has remained enigmatic. Improvement of immunological treatability is an urgent clinical concern. We retrospectively assessed the clinical, MRI and CSF course as well as brain tissue of 15 adult patients with GAD-TLE who underwent temporal lobe surgery. Brain tissue was studied by means of immunohistochemistry, multiplex fluorescent microscopy and transcriptomic analysis for inflammatory mediators and neuronal degeneration. In 10 patients, there was a period of mediotemporal swelling and T2 signal increase; in nine cases this occurred within the first 6 years after symptom onset. This resulted in unilateral or bilateral hippocampal sclerosis; three cases developed hippocampal sclerosis within the first 2 years. All CSF studies done within the first year (n = 6) revealed intrathecal synthesis of immunoglobulin G. Temporal lobe surgeries were done after a median disease duration of 9 years (range 3 weeks to 60 years). Only two patients became seizure-free. Brain parenchyma collected during surgery in the first 6 years revealed high numbers of plasma cells but no signs of antibody-mediated tissue damage. Even more dense was the infiltration by CD8+ cytotoxic T lymphocytes (CTLs) that were seen to locally proliferate. Further, a portion of these cells revealed an antigen-specific resident memory T cell phenotype. Finally, CTLs with cytotoxic granzyme B+ granules were also seen in microglial nodules and attached to neurons, suggesting a CTL-mediated destruction of these cells. With longer disease duration, the density of all lymphocytes decreased. Whole transcriptome analysis in early/active cases (but not in late/inactive stages) revealed 'T cell immunity' and 'Regulation of immune processes' as the largest overrepresented clusters. To a lesser extent, pathways associated with B cells and neuronal degeneration also showed increased representation. Surgically treated patients with GAD-TLE go through an early active inflammatory, 'encephalitic' stage (≤6 years) with CTL-mediated, antigen-driven neuronal loss and antibody-producing plasma cells but without signs of complement-mediated cell death. Subsequently, patients enter an apparently immunologically inactive or low-active stage with ongoing seizures, probably caused by the structural damage to the temporal lobe. 'Limbic encephalitis' with GAD antibodies should be subsumed under GAD-TLE. The early tissue damage explains why immunotherapy does not usually lead to freedom from seizures.

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.

Leucine-rich Glioma-inactivated 1 Encephalitis Followed by Isaacs Syndrome: Alternating Presence of Pathogenic Autoantibodies to Leucine-rich Glioma-inactivated 1 and Contactin-associated Protein-like 2.

The coexistence of leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) autoantibodies in the same individual is surprisingly often observed. We herein report the first case of LGI1 encephalitis followed by Isaacs syndrome in which LGI1 and CASPR2 antibodies in the serum and cerebrospinal fluid (CSF) were measured during the entire disease course. After the resolution of limbic encephalitis, LGI1 antibodies disappeared from the CSF simultaneously with the appearance of CASPR2 antibodies in the serum. The alternating presence of these pathogenic autoantibodies along with the clinical and phenotypic alternations suggested that LGI1 encephalitis was associated with CASPR2 autoantibody production in the peripheral tissue, leading to CASPR2-associated Isaacs syndrome.

Immune-mediated diseases involving central and peripheral nervous systems.

BACKGROUND AND PURPOSE: In addition to combined central and peripheral demyelination, other immune diseases could involve both the central nervous system (CNS) and peripheral nervous system (PNS). METHODS: To identify immune-mediated diseases responsible for symptomatic combined central/peripheral nervous system involvement (ICCPs), we conducted a multicentric retrospective study and assessed clinical, electrophysiological, and radiological features of patients fulfilling our ICCP criteria. RESULTS: Thirty patients (20 males) were included and followed during a median of 79.5 months (interquartile range [IQR] = 43-145). The median age at onset was 51.5 years (IQR = 39-58). Patients were assigned to one of four groups: (i) monophasic disease with concomitant CNS/PNS involvement including anti-GQ1b syndrome (acute polyradiculoneuropathy + rhombencephalitis, n = 2), checkpoint inhibitor-related toxicities (acute polyradiculoneuropathy + encephalitis, n = 3), and anti-glial fibrillary acidic protein astrocytopathy (subacute polyradiculoneuropathy and meningoencephalomyelitis with linear gadolinium enhancements, n = 2); (ii) chronic course with concomitant CNS/PNS involvement including paraneoplastic syndromes (ganglionopathy/peripheral hyperexcitability + limbic encephalitis, n = 4); (iii) chronic course with sequential CNS/PNS involvement including POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) syndrome (polyradiculoneuropathy + strokes, n = 2), histiocytosis (polyradiculoneuropathy + lepto-/pachymeningitis, n = 1), and systemic vasculitis (multineuropathy + CNS vasculitis/pachymeningitis, n = 2); and (iv) chronic course with concomitant or sequential CNS/PNS involvement including combined central and peripheral demyelination (polyradiculoneuropathy + CNS demyelinating lesions, n = 10) and connective tissue diseases (ganglionopathy/radiculopathy/multineuropathy + limbic encephalitis/transverse myelitis/stroke, n = 4). CONCLUSIONS: We diagnosed nine ICCPs. The timing of central and peripheral manifestations and the disease course help determine the underlying immune disease. When antibody against neuroglial antigen is identified, CNS and PNS involvement is systematically concomitant, suggesting a common CNS/PNS antigen and a simultaneous disruption of blood-nerve and blood-brain barriers.

Impact and Risk Factors of Limbic Predominant Age-Related TDP-43 Encephalopathy Neuropathologic Change in an Oldest-Old Cohort.

BACKGROUND AND OBJECTIVES: Limbic predominant age-related TAR DNA binding protein 43 (TDP-43) encephalopathy neuropathologic change (LATE-NC) is a prevalent degenerative pathology in the oldest-old who are the fastest-growing segment of our population with the highest rates of dementia. We aimed to determine the relationship between LATE-NC and cognitive impairment and to identify its potential risk factors by studying its relationship with common past medical histories in an oldest-old cohort. METHODS: Participants from The 90+ Study with longitudinal evaluations and autopsy data were included. Dementia status and impairment in 5 main cognitive domains were determined at postmortem conferences leveraging all clinical and neuropsychological data blind to neuropathologic diagnosis. Medical history information was obtained from patients and their informants. LATE-NC and Alzheimer disease neuropathologic change (ADNC) were considered present in those with TDP-43 pathology in the hippocampus and/or neocortex and those with high likelihood of ADNC according to NIA-AA guidelines, respectively. We examined the association of degenerative pathologies with cognitive outcomes and multiple comparisons-adjusted relationship of medical history variables with LATE-NC and ADNC using logistic regressions adjusted for age at death, sex, and education. RESULTS: Three hundred twenty-eight participants were included in this study. LATE-NC was present in 32% of the participants. It had a significant association with the presence of dementia (OR 2.8, 95% CI 1.7-4.6) and impairment in memory (OR 3.0, 95% CI 1.8-5.1), language (OR 2.6, 95% CI 1.6-4.3), and orientation (OR 3.5, 95% CI 2.1-5.9). The association with impaired orientation was unique to LATE-NC, and the strength and significance of the other associations were comparable to ADNC. Furthermore, we found that history of osteoarthritis (OR 0.37, adjusted 95% CI 0.21-0.66) and hypertension (OR 0.52, adjusted 95% CI 0.28-0.98) were associated with a reduced likelihood of LATE-NC, but not ADNC. DISCUSSION: Our results suggest that LATE-NC is a prevalent degenerative pathology in the oldest-old and has significant associations with dementia and impairment in cognitive domains with magnitudes that are comparable to ADNC. We also found that past medical histories of hypertension and osteoarthritis were associated with a lower likelihood of LATE-NC. This might help identify upstream mechanisms leading to this important pathology.

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.

Anti-leucine-rich glioma-inactivated 1 encephalitis: two case reports and a review of the literature.

BACKGROUND: Anti-leucine-rich glioma-inactivated 1 encephalitis is a newly emerged entity characterized by frequent faciobrachial dystonic seizures and a wide spectrum of subacute clinical symptoms such as other seizure types, mood and behavioral changes, and memory loss. We should be aware of differentiating this diagnosis from psychogenic nonepileptic seizures. Mesial temporal, limbic structures, and basal ganglia are the most commonly involved regions. CASE PRESENTATION: Here we review the available data, and report on two young Iranian (White) females, 24 and 18 years old, who represent distinct aspects of the disease. The clinical presentation and degree of tissue involvement varies to some extent in the two reported cases. Case 1 had prominent neuropsychiatric symptoms and suffered from frequent faciobrachial dystonic seizures with more significant basal ganglia involvement, whereas case 2 suffered from severe memory decline and dialeptic seizures along with mesial temporal involvement. Symptoms were refractory to usual treatment and prompt immunotherapy was needed. CONCLUSIONS: This disease has a rather favorable outcome provided that treatment is initiated early. However, resistance to first-line treatment, relapses, and long-term complications highlight the need to establish reliable biomarkers to distinguish different subtypes of this disorder to predict the clinical outcome and prognosis, and to refine management.