GABAA receptor and LGI1 antibody encephalitis in a patient with thymoma.
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ABSTRACT:
SUBMITTER: Simabukuro MM
PROVIDER: S-EPMC4335819 | biostudies-literature | 2015 Apr
REPOSITORIES: biostudies-literature
Publications
GABAA receptor and LGI1 antibody encephalitis in a patient with thymoma.
Simabukuro Mateus Mistieri MM Petit-Pedrol Mar M Castro Luiz H LH Nitrini Ricardo R Lucato Leandro L Zambon Antônio Alberto AA Silva Lis Gomes LG Fortes Gabriela Carneiro Rosa GC Soares Neto Herval Ribeiro HR Dalmau Josep O JO
Neurology(R) neuroimmunology & neuroinflammation 20150212 2
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Project description:We report a 77-year-old woman with a thymoma, anti-LGI1antibody associated encephalitis (LGI1 encephalitis), and MG accompanied by positive anti-acetylcholine receptor antibodies (AchR Ab) and anti-titin antibodies (titin Ab). She was treated with thymomectomy followed by immunosuppressive therapy, which resulted in immediate amelioration of motor weakness and gradual improvement of cognitive impairment over the next two years. LGI1 Ab were positive at two months after thymomectomy, followed by negative conversion demonstrated on 1 year examination. The AchR Ab level had gradually decreased but titin Ab was positive on re-examination after two years, although the cognition and motor impairment symptoms had been alleviated. In patients with suspected autoimmune encephalitis, the detection of several autoantibodies including LGI1 and thymomas provides useful information for making an accurate diagnosis.
| S-EPMC8919234 | biostudies-literature
Project description:Autoantibodies targeting the GABAA receptor (GABAAR) hallmark an autoimmune encephalitis presenting with frequent seizures and psychomotor abnormalities. Their pathogenic role is still not well-defined, given the common overlap with further autoantibodies and the lack of patient-derived mAbs. Five GABAAR mAbs from cerebrospinal fluid cells bound to various epitopes involving the α1 and γ2 receptor subunits, with variable binding strength and partial competition. mAbs selectively reduced GABAergic currents in neuronal cultures without causing receptor internalization. Cerebroventricular infusion of GABAAR mAbs and Fab fragments into rodents induced a severe phenotype with seizures and increased mortality, reminiscent of encephalitis patients' symptoms. Our results demonstrate direct pathogenicity of autoantibodies on GABAARs independent of Fc-mediated effector functions and provide an animal model for GABAAR encephalitis. They further provide the scientific rationale for clinical treatments using antibody depletion and can serve as tools for the development of antibody-selective immunotherapies.
| S-EPMC8480667 | biostudies-literature
Project description:BackgroundWhile brain asymmetry has been a fascinating issue in neuroscience, the critical mechanism remains to be elucidated. Based on some index cases with asymmetric 18F-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) uptake in leucine-rich glioma-inactivated 1 (LGI1)-antibody encephalitis, we hypothesized LGI1 expression could be asymmetrically distributed in the human brain.MethodsWe enrolled 13 patients who were diagnosed with LGI1-antibody encephalitis between June 2012 and January 2018 at Seoul National University Hospital. Their pretreatment 18F-FDG-PET images were analyzed to find asymmetry between the left and right hemispheres. Guided by these observations, expression of LGI1 in the human hippocampus and the globus pallidus of both cerebral hemispheres was studied in nine post-mortem human brains.ResultsEleven of the 13 LGI1-antibody encephalitis patients (84.6%) showed asymmetrical FDG high uptake in the hippocampus: nine (81.8%) on the left hippocampus and two (18.2%) on the right. In the basal ganglia, seven patients (53.8%) showed asymmetry: four (57.1%) on the left and three (42.9%) on the right. The asymmetry was not evident in the laterality of faciobrachial dystonic seizures, brain MRI, and EEG. When the expression of LGI1 protein was analyzed in nine post-mortem human brains by western blotting, LGI1 expression was higher on eight left globus pallidus samples (88.89%, P = 0.019) and on four left hippocampal samples (44.44%, P = 0.652), compared to their right hemisphere samples.ConclusionsImaging parameters from patients with LGI1-antibody encephalitis and studies of LGI1 protein expression suggest that LGI1 is asymmetrically distributed in the human brain. These observations have implications for our understanding of human brain development.
| S-EPMC6156957 | biostudies-literature
Project description:ImportanceRapid and accurate diagnosis of autoimmune encephalitis encourages prompt initiation of immunotherapy toward improved patient outcomes. However, clinical features alone may not sufficiently narrow the differential diagnosis, and awaiting autoantibody results can delay immunotherapy.ObjectiveTo identify simple magnetic resonance imaging (MRI) characteristics that accurately distinguish 2 common forms of autoimmune encephalitis, LGI1- and CASPR2-antibody encephalitis (LGI1/CASPR2-Ab-E), from 2 major differential diagnoses, viral encephalitis (VE) and Creutzfeldt-Jakob disease (CJD).Design, setting, and participantsThis cross-sectional study involved a retrospective, blinded analysis of the first available brain MRIs (taken 2000-2022) from 192 patients at Oxford University Hospitals in the UK and Mayo Clinic in the US. These patients had LGI1/CASPR2-Ab-E, VE, or CJD as evaluated by 2 neuroradiologists (discovery cohort; n = 87); findings were validated in an independent cohort by 3 neurologists (n = 105). Groups were statistically compared with contingency tables. Data were analyzed in 2023.Main outcomes and measuresMRI findings including T2 or fluid-attenuated inversion recovery (FLAIR) hyperintensities, swelling or volume loss, presence of gadolinium contrast enhancement, and diffusion-weighted imaging changes. Correlations with clinical features.ResultsAmong 192 participants with MRIs reviewed, 71 were female (37%) and 121 were male (63%); the median age was 66 years (range, 19-92 years). By comparison with VE and CJD, in LGI1/CASPR2-Ab-E, T2 and/or FLAIR hyperintensities were less likely to extend outside the temporal lobe (3/42 patients [7%] vs 17/18 patients [94%] with VE; P < .001, and 3/4 patients [75%] with CJD; P = .005), less frequently exhibited swelling (12/55 [22%] with LGI1/CASPR2-Ab-E vs 13/22 [59%] with VE; P = .003), and showed no diffusion restriction (0 patients vs 16/22 [73%] with VE and 8/10 [80%] with CJD; both P < .001) and rare contrast enhancement (1/20 [5%] vs 7/17 [41%] with VE; P = .01). These findings were validated in an independent cohort and generated an area under the curve of 0.97, sensitivity of 90%, and specificity of 95% among cases with T2/FLAIR hyperintensity in the hippocampus and/or amygdala.Conclusions and relevanceIn this study, T2 and/or FLAIR hyperintensities confined to the temporal lobes, without diffusion restriction or contrast enhancement, robustly distinguished LGI1/CASPR2-Ab-E from key differential diagnoses. These observations should assist clinical decision-making toward expediting immunotherapy. Their generalizability to other forms of autoimmune encephalitis and VE should be examined in future studies.
| S-EPMC10949153 | biostudies-literature
Project description: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.
| S-EPMC9856817 | biostudies-literature
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| S-EPMC3390544 | biostudies-literature
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| S-EPMC5802484 | biostudies-literature
Project description:We utilise a clinical case to highlight why exclusion of voltage-gated potassium channel (VGKC)-complex autoantibody testing in serological evaluation of patients may delay or miss the diagnosis. A 68-year-old man presented with increasing involuntary movements consistent with faciobrachial dystonic seizures (FBDS). Initial evaluation demonstrated VGKC antibody seropositivity with leucine-rich glioma-inactivated 1 (LGI1) and contactin-associated protein-like 2 (CASPR2) seronegativity. Aggressive immunotherapy with methylprednisolone and plasmapheresis was started early in the course of his presentation. Following treatment with immunotherapy, the patient demonstrated clinical improvement. Repeat serum evaluation 4 months posthospitalisation remained seropositive for VGKC-complex antibodies, with development of LGI1 autoantibody seropositivity. VGKC-complex and LGI1 antibodies remained positive 12 months posthospitalisation. Our findings suggest that clinical symptoms can predate the detection of the antibody. We conclude that when suspicion for autoimmune encephalitis is high in the setting of VGKC autoantibody positivity, regardless of LGI1 or CASPR2 seropositivity, early immunotherapy and repeat testing should be considered.
| S-EPMC5534759 | biostudies-other
Project description:PurposeTo describe clinical and electrographic characteristics of seizures LGI1-antibody encephalitis, and their correlations with two-year outcomes.MethodsVideo-electroencephalography recordings were performed on a cohort of 16 consecutive patients with LGI1-antibodies from two UK neuroscience-centers over five-years.ResultsFrom 14 of 16 patients (13 males; age-range 53-92years), 86 faciobrachial dystonic seizures were recorded at a median frequency of 0.4 per hour (range 0.1-9.8), and ictal EEG changes accompanied 5/86 events. In addition, 11/16 patients showed 53 other seizures - subclinical (n=18), motor (n=16), or sensory (n=19) - at a median of 0.1 per hour (range 0.1-2) associated with temporal and frontal discharges. The sensory events were most commonly thermal sensations or body-shuddering, and the motor events were frequently automatisms or vocalisations. Furthermore, multifocal interictal epileptiform discharges, from temporal, frontal and parietal regions, and interictal slow-wave activity were observed in 25% and 69% of patients, respectively. Higher observed seizure frequency correlated with poorer functional recovery at two-years (p=0.001).ConclusionsMultiple frequent seizure semiologies, in addition to numerous subclinical seizures and interictal epileptiform discharges, are hallmarks of LGI1-antibody encephalitis. High overall seizure frequency may predict more limited long-term recovery. These observations should encourage closer monitoring and proactive treatment of seizure activity in these patients.
| S-EPMC5558811 | biostudies-literature
Project description:Magnetic resonance imaging has linked chronic voltage-gated potassium channel (VGKC) complex antibody-mediated limbic encephalitis with generalized hippocampal atrophy. However, autoantibodies bind to specific rodent hippocampal subfields. Here, human hippocampal subfield (subiculum, cornu ammonis 1-3, and dentate gyrus) targets of immunomodulation-treated LGI1 VGKC-complex antibody-mediated limbic encephalitis were investigated using in vivo ultra-high resolution (0.39 × 0.39 × 1.0 mm3) 7.0 T magnetic resonance imaging [n = 18 patients, 17 patients (94%) positive for LGI1 antibody and one patient negative for LGI1/CASPR2 but positive for VGKC-complex antibodies, mean age: 64.0 ± 2.55 years, median 4 years post-limbic encephalitis onset; n = 18 controls]. First, hippocampal subfield quantitative morphometry indicated significant volume loss confined to bilateral CA3 [F(1,34) = 16.87, P < 0.0001], despite hyperintense signal evident in 5 of 18 patients on presentation. Second, early and later intervention (<3 versus >3 months from symptom onset) were associated with CA3 atrophy. Third, whole-brain voxel-by-voxel morphometry revealed no significant grey matter loss. Fourth, CA3 subfield atrophy was associated with severe episodic but not semantic amnesia for postmorbid autobiographical events that was predicted by variability in CA3 volume. The results raise important questions about the links with histopathology, the impact of the observed focal atrophy on other CA3-mediated reconstructive and episodic mechanisms, and the role of potential antibody-mediated pathogenicity as part of the pathophysiology cascade in humans.
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