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Dorcet G, Benaiteau M, Pariente J, Ory‐Magne F, Cheuret E, Rafiq M, Brooks W, Puissant‐Lubrano B, Fortenfant F, Renaudineau Y, Bost C. Cerebrospinal fluid YKL-40 level evolution is associated with autoimmune encephalitis remission. Clin Transl Immunology 2023; 12:e1439. [PMID: 36938371 PMCID: PMC10015376 DOI: 10.1002/cti2.1439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/06/2022] [Accepted: 02/04/2023] [Indexed: 03/17/2023] Open
Abstract
Objective Because of its heterogeneity in clinical presentation and course, predicting autoimmune encephalitis (AIE) evolution remains challenging. Hence, our aim was to explore the correlation of several biomarkers with the clinical course of disease. Methods Thirty-seven cases of AIE were selected retrospectively and divided into active (N = 9), improved (N = 12) and remission (N = 16) AIE according to their disease evolution. Nine proteins were tested in both serum and cerebrospinal fluid (CSF) at diagnosis (T0) and during the follow-up (T1), in particular activated MMP-9 (MMP-9A) and YKL-40 (or chitinase 3-like 1). Results From diagnosis to revaluation, AIE remission was associated with decreased YKL-40 and MMP-9A levels in the CSF, and with decreased NfL and NfH levels in the serum. The changes in YKL-40 concentrations in the CSF were associated with (1) still active AIE when increasing >10% (P-value = 0.0093); (2) partial improvement or remission when the changes were between +9% and -20% (P-value = 0.0173); and remission with a reduction > -20% (P-value = 0.0072; overall difference between the three groups: P-value = 0.0088). At T1, the CSF YKL-40 levels were significantly decreased between active and improved as well as improved and remission AIE groups but with no calculable threshold because of patient heterogeneity. Conclusion The concentration of YKL-40, a cytokine-like proinflammatory protein produced by glial cells, is correlated in the CSF with the clinical course of AIE. Its introduction as a biomarker may assist in following disease activity and in evaluating therapeutic response.
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Affiliation(s)
- Guillaume Dorcet
- Département de NeurologieHôpital Pierre Paul Riquet, CHU de ToulouseToulouseFrance
- Laboratoire d'ImmunologieInstitut Fédératif de Biologie, CHU de ToulouseToulouseFrance
- INSERM, INFINITyToulouseFrance
| | - Marie Benaiteau
- Département de NeurologieHôpital Pierre Paul Riquet, CHU de ToulouseToulouseFrance
| | - Jérémie Pariente
- Département de NeurologieHôpital Pierre Paul Riquet, CHU de ToulouseToulouseFrance
- INSERM, ToNICToulouseFrance
| | - Fabienne Ory‐Magne
- Département de NeurologieHôpital Pierre Paul Riquet, CHU de ToulouseToulouseFrance
| | - Emmanuel Cheuret
- Unité Pédiatrique Neuro‐céphaliqueHôpital des Enfants, CHU de ToulouseToulouseFrance
| | - Marie Rafiq
- Département de NeurologieHôpital Pierre Paul Riquet, CHU de ToulouseToulouseFrance
- INSERM, ToNICToulouseFrance
| | - Wesley Brooks
- Department of ChemistryUniversity of South FloridaTampaFLUSA
| | - Bénédicte Puissant‐Lubrano
- Laboratoire d'ImmunologieInstitut Fédératif de Biologie, CHU de ToulouseToulouseFrance
- INSERM, INFINITyToulouseFrance
| | - Françoise Fortenfant
- Laboratoire d'ImmunologieInstitut Fédératif de Biologie, CHU de ToulouseToulouseFrance
| | - Yves Renaudineau
- Laboratoire d'ImmunologieInstitut Fédératif de Biologie, CHU de ToulouseToulouseFrance
- INSERM, INFINITyToulouseFrance
| | - Chloé Bost
- Laboratoire d'ImmunologieInstitut Fédératif de Biologie, CHU de ToulouseToulouseFrance
- INSERM, INFINITyToulouseFrance
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2
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Chen TS, Lai MC, Huang HYI, Wu SN, Huang CW. Immunity, Ion Channels and Epilepsy. Int J Mol Sci 2022; 23:ijms23126446. [PMID: 35742889 PMCID: PMC9224225 DOI: 10.3390/ijms23126446] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 12/10/2022] Open
Abstract
Epilepsy is a common chronic neurological disorder in modern society. One of the major unmet challenges is that current antiseizure medications are basically not disease-modifying. Among the multifaceted etiologies of epilepsy, the role of the immune system has attracted considerable attention in recent years. It is known that both innate and adaptive immunity can be activated in response to insults to the central nervous system, leading to seizures. Moreover, the interaction between ion channels, which have a well-established role in epileptogenesis and epilepsy, and the immune system is complex and is being actively investigated. Some examples, including the interaction between ion channels and mTOR pathways, will be discussed in this paper. Furthermore, there has been substantial progress in our understanding of the pathophysiology of epilepsy associated with autoimmune encephalitis, and numerous neural-specific autoantibodies have been found and documented. Early recognition of immune-mediated epilepsy is important, especially in cases of pharmacoresistant epilepsy and in the presence of signs of autoimmune encephalitis, as early intervention with immunotherapy shows promise.
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Affiliation(s)
- Tsang-Shan Chen
- Department of Neurology, Tainan Sin-Lau Hospital, Tainan 701002, Taiwan;
| | - Ming-Chi Lai
- Department of Pediatrics, Chi-Mei Medical Center, Tainan 71004, Taiwan;
| | | | - Sheng-Nan Wu
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan;
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 70101, Taiwan
| | - Chin-Wei Huang
- Department of Neurology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
- Correspondence: ; Tel.: +886-6-2353535 (ext. 5485)
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3
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Zografou C, Vakrakou AG, Stathopoulos P. Short- and Long-Lived Autoantibody-Secreting Cells in Autoimmune Neurological Disorders. Front Immunol 2021; 12:686466. [PMID: 34220839 PMCID: PMC8248361 DOI: 10.3389/fimmu.2021.686466] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/28/2021] [Indexed: 12/24/2022] Open
Abstract
As B cells differentiate into antibody-secreting cells (ASCs), short-lived plasmablasts (SLPBs) are produced by a primary extrafollicular response, followed by the generation of memory B cells and long-lived plasma cells (LLPCs) in germinal centers (GCs). Generation of IgG4 antibodies is T helper type 2 (Th2) and IL-4, -13, and -10-driven and can occur parallel to IgE, in response to chronic stimulation by allergens and helminths. Although IgG4 antibodies are non-crosslinking and have limited ability to mobilize complement and cellular cytotoxicity, when self-tolerance is lost, they can disrupt ligand-receptor binding and cause a wide range of autoimmune disorders including neurological autoimmunity. In myasthenia gravis with predominantly IgG4 autoantibodies against muscle-specific kinase (MuSK), it has been observed that one-time CD20+ B cell depletion with rituximab commonly leads to long-term remission and a marked reduction in autoantibody titer, pointing to a short-lived nature of autoantibody-secreting cells. This is also observed in other predominantly IgG4 autoantibody-mediated neurological disorders, such as chronic inflammatory demyelinating polyneuropathy and autoimmune encephalitis with autoantibodies against the Ranvier paranode and juxtaparanode, respectively, and extends beyond neurological autoimmunity as well. Although IgG1 autoantibody-mediated neurological disorders can also respond well to rituximab induction therapy in combination with an autoantibody titer drop, remission tends to be less long-lasting and cases where titers are refractory tend to occur more often than in IgG4 autoimmunity. Moreover, presence of GC-like structures in the thymus of myasthenic patients with predominantly IgG1 autoantibodies against the acetylcholine receptor and in ovarian teratomas of autoimmune encephalitis patients with predominantly IgG1 autoantibodies against the N‐methyl‐d‐aspartate receptor (NMDAR) confers increased the ability to generate LLPCs. Here, we review available information on the short-and long-lived nature of ASCs in IgG1 and IgG4 autoantibody-mediated neurological disorders and highlight common mechanisms as well as differences, all of which can inform therapeutic strategies and personalized medical approaches.
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Affiliation(s)
- C Zografou
- Institute of Neuropathology, University of Zurich, Zurich, Switzerland
| | - A G Vakrakou
- First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - P Stathopoulos
- First Department of Neurology, National and Kapodistrian University of Athens Medical School, Athens, Greece
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4
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Wen X, Wang B, Wang C, Han C, Guo S. A Retrospective Study of Patients with GABA BR Encephalitis: Therapy, Disease Activity and Prognostic Factors. Neuropsychiatr Dis Treat 2021; 17:99-110. [PMID: 33500619 PMCID: PMC7822224 DOI: 10.2147/ndt.s289942] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 12/23/2020] [Indexed: 01/13/2023] Open
Abstract
PURPOSE To explore the effects of immunotherapy and tumour treatment on patients with GABABR encephalitis, evaluate the correlation between immune cell subsets and disease activity, and investigate effective prognostic factors. PATIENTS AND METHODS Twenty patients with γ-aminobutyric acid B receptor (GABABR) encephalitis were enrolled from December 2015 to April 2020. The clinical data, modified Rankin Scale (mRS) score, prognosis and percentage of serum lymphocytes were recorded. RESULTS All patients received first-line immunotherapy. The median mRS scores were 4 and 3 before and after first-line immunotherapy (P<0.01). Seven patients received second-line immunotherapy and had median mRS scores of 3 and 2 before and after second-line immunotherapy (P=0.015). Small-cell lung cancer was detected in twelve patients. Among the patients who died because of tumours, patients who received tumour treatment lived longer than patients who did not receive tumour treatment (P=0.025). All four surviving patients who received tumour treatment had good outcomes (mRS≤2). The median serum CD19+B cell percentage in sixteen patients were 20.00% and 13.42% prior first-line immunotherapy and at the last follow-up (P<0.01). After a maximum follow-up of 54 months (median: 12; range: 3-54), eleven patients (55%) had a poor prognosis (mRS>2). Predictors of a poor prognosis were older age (P=0.031), delayed initial improvement after immunotherapy (>4 weeks) (P=0.038) and respiratory failure (P=0.038). CONCLUSION Aggressive immunotherapy and tumour treatment contribute to improvements in neurological function and a better prognosis of patients with GABABR encephalitis. The serum CD19+B cell percentage may be an indicator of disease activity. Older age, delayed initial improvement after immunotherapy, and respiratory failure may be associated with poor outcomes.
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Affiliation(s)
- Xiangchuan Wen
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, People's Republic of China
| | - Baojie Wang
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, People's Republic of China
| | - Chunjuan Wang
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, People's Republic of China.,Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, People's Republic of China
| | - Chenglin Han
- Department of Urology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, People's Republic of China
| | - Shougang Guo
- Department of Neurology, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250021, People's Republic of China.,Department of Neurology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong 250021, People's Republic of China
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5
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Reyazuddin M, Shaan F, Azmi SA. A case of anti-LGI-1 encephalitis presented as acute psychosis. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2020. [DOI: 10.1186/s41983-020-00196-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
AbstractAnti-leucine-rich glioma inactivated protein-1 (LGI-1) encephalitis is a rare autoimmune disease with a varied neuropsychiatric clinical manifestation and have potential for reversal with immunotherapy. Early identification and treatment are therefore of paramount importance. We present the case of a 43-year-old man admitted for acute psychosis with facio-brachial dystonic seizures not responding to anti-epileptic drugs (AEDs). His symptoms started approximately 5 months prior admission to the hospital and associated with progressive cognitive impairment (particularly verbal and visio-spatial domains) followed by altered behavior, irrelevant talk, and disturbance in daily activities of living and facio-brachial dystonic seizures. There was history of allergic reaction to valproate, carbamazepine and levetiracetam, and serum sample tested strongly positive for LGI-1 (leucine rich glioma inactivated-1) antibodies. He was treated with injection methylprednisolone (1 gm intravenous) brief pulse therapy for 7 days and then underwent four sessions of plasma exchange followed by oral steroids and immunosuppressant therapy. Treatment was successful and patient returned to his previous baseline functioning but patient develops steroid induced hypomania and diabetes mellitus in the due course of time. Patient was discharged after successful resolution of symptoms. Patient did not come up for follow-up. He was contacted telephonically and we get to know that he relapsed after 2 weeks and consulted at higher center where he died while on treatment. Prognosis of anti-LGI-1 encephalitis is usually good but our patient died.
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Vogrig A, Muñiz-Castrillo S, Desestret V, Joubert B, Honnorat J. Pathophysiology of paraneoplastic and autoimmune encephalitis: genes, infections, and checkpoint inhibitors. Ther Adv Neurol Disord 2020; 13:1756286420932797. [PMID: 32636932 PMCID: PMC7318829 DOI: 10.1177/1756286420932797] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 05/17/2020] [Indexed: 12/14/2022] Open
Abstract
Paraneoplastic neurological syndromes (PNSs) are rare complications of systemic cancers that can affect all parts of the central and/or peripheral nervous system. A body of experimental and clinical data has demonstrated that the pathogenesis of PNSs is immune-mediated. Nevertheless, the mechanisms leading to immune tolerance breakdown in these conditions remain to be elucidated. Despite their rarity, PNSs offer a unique perspective to understand the complex interplay between cancer immunity, effect of immune checkpoint inhibitors (ICIs), and mechanisms underlying the attack of neurons in antibody-mediated neurological disorders, with potentially relevant therapeutic implications. In particular, it is reported that ICI treatment can unleash PNSs and that the immunopathological features of PNS-related tumors are distinctive, showing prominent tumor-infiltrating lymphocytes and germinal center reactions. Intriguingly, similar pathological substrates have gained further attention as potential biomarkers of ICI-sensitivity and oncological prognosis. Moreover, the genetic analysis of PNS-associated tumors has revealed specific molecular signatures and mutations in genes encoding onconeural proteins, leading to the production of highly immunogenic neoantigens. Other than PNSs, autoimmune encephalitides (AEs) comprise a recently described group of disorders characterized by prominent neuropsychiatric symptoms, diverse antibody spectrum, and less tight association with cancer. Other triggering factors seem to be involved in AEs. Recent data have shed light on the importance of preceding infections (in particular, herpes simplex virus encephalitis) in inducing neurological autoimmune disorders in susceptible individuals (those with a selective deficiency in the innate immune system). In addition, in some AEs (e.g. LGI1-antibody encephalitis) an association with specific host-related factors [e.g., human leukocyte antigen (HLA)] was clearly demonstrated. We provide herein a comprehensive review of the most recent findings in the field of PNSs and AEs, with particular focus on their triggering factors and immunopathogenesis.
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Affiliation(s)
- Alberto Vogrig
- French Reference Center for Paraneoplastic Neurological Syndromes, Hospices Civils de Lyon, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Lyon, France
- SynatAc Team, NeuroMyoGene Institute, INSERM U1217/CNRS UMR5310, Lyon, France
- University Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Sergio Muñiz-Castrillo
- French Reference Center for Paraneoplastic Neurological Syndromes, Hospices Civils de Lyon, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Lyon, France
- SynatAc Team, NeuroMyoGene Institute, INSERM U1217/CNRS UMR5310, Lyon, France
- University Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Virginie Desestret
- French Reference Center for Paraneoplastic Neurological Syndromes, Hospices Civils de Lyon, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Lyon, France
- SynatAc Team, NeuroMyoGene Institute, INSERM U1217/CNRS UMR5310, Lyon, France
- University Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Bastien Joubert
- French Reference Center for Paraneoplastic Neurological Syndromes, Hospices Civils de Lyon, Hospital for Neurology and Neurosurgery Pierre Wertheimer, Lyon, France
- SynatAc Team, NeuroMyoGene Institute, INSERM U1217/CNRS UMR5310, Lyon, France
- University Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Jérôme Honnorat
- Centre de Référence National pour les Syndromes Neurologiques Paranéoplasiques, Hôpital Neurologique, 59 Boulevard Pinel, Bron Cedex, 69677, France
- SynatAc Team, NeuroMyoGene Institute, INSERM U1217/CNRS UMR5310, Lyon, France
- University Claude Bernard Lyon 1, Université de Lyon, Lyon, France
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7
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Dorcet G, Benaiteau M, Bost C, Mengelle C, Bonneville F, Martin-Blondel G, Pariente J. Two Cases of Late-Onset Anti-NMDAr Auto-Immune Encephalitis After Herpes Simplex Virus 1 Encephalitis. Front Neurol 2020; 11:38. [PMID: 32132963 PMCID: PMC7040193 DOI: 10.3389/fneur.2020.00038] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 01/10/2020] [Indexed: 11/13/2022] Open
Abstract
Context: Encephalitis due to herpes simplex virus 1 (HSV-1) was described as a potential trigger for the development of anti-N-methyl-D-aspartate receptor (NMDAr) auto-immune encephalitis (AIE) within a few days to a few weeks after the infection. Methods: We assessed clinical, radiological, and biological diagnoses process, treatment response, and evolution. Cases Reported: We report here cases of a 71-year-old man and a 57-year-old woman presenting anti-NMDAr AIE, respectively, 12 and 7 months after HSV-1 encephalitis. In both cases, the onset was brisk, and the symptoms were mainly neuropsychiatric (paranoid delirium, Capgras, and Cotard syndromes) and cognitive, with anterograde amnesia. Relapse of HSV encephalitis, epilepsy, and paraneoplastic neurologic syndromes were excluded. The clinical response to first-line treatments composed of intravenous immunoglobulins and high-dose corticosteroids was poor, whereas significant improvement was noticed after rituximab induction. Conclusion: Post-herpetic anti-NMDAr AIE could arise several months after infection. Clinicians must be aware of this possibility, particularly if cognitive and/or psychiatric symptoms occurred after a remitting period. In our two cases, only rituximab was associated with clinical improvement.
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Affiliation(s)
- Guillaume Dorcet
- Département de Neurologie, Hôpital Pierre Paul Riquet, CHU de Toulouse, Toulouse, France
| | - Marie Benaiteau
- Département de Neurologie, Hôpital Pierre Paul Riquet, CHU de Toulouse, Toulouse, France
| | - Chloé Bost
- Laboratoire d'Immunologie, Institut Fédératif de Biologie, CHU de Toulouse, Toulouse, France.,INSERM U1043 - CNRS UMR 5282, Centre de Physiopathologie Toulouse-Purpan, Toulouse, France
| | - Catherine Mengelle
- Laboratoire de Virologie, Institut Fédératif de Biologie, CHU de Toulouse, Toulouse, France
| | - Fabrice Bonneville
- Service de Neuroradiologie, Hôpital Pierre Paul Riquet, CHU de Toulouse, Toulouse, France.,INSERM: ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, Université Paul Sabatier, Toulouse, France
| | - Guillaume Martin-Blondel
- INSERM U1043 - CNRS UMR 5282, Centre de Physiopathologie Toulouse-Purpan, Toulouse, France.,Service de Maladies Infectieuses et Transmissibles, Bâtiment Urgences Réanimation Médecine, CHU de Toulouse, Toulouse, France
| | - Jérémie Pariente
- Département de Neurologie, Hôpital Pierre Paul Riquet, CHU de Toulouse, Toulouse, France.,INSERM: ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, Université Paul Sabatier, Toulouse, France
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8
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Muñiz-Castrillo S, Vogrig A, Honnorat J. Associations between HLA and autoimmune neurological diseases with autoantibodies. AUTOIMMUNITY HIGHLIGHTS 2020; 11:2. [PMID: 32127039 PMCID: PMC7065322 DOI: 10.1186/s13317-019-0124-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/14/2019] [Indexed: 12/16/2022]
Abstract
Recently, several autoimmune neurological diseases have been defined by the presence of autoantibodies against different antigens of the nervous system. These autoantibodies have been demonstrated to be specific and useful biomarkers, and most of them are also pathogenic. These aspects have increased the value of autoantibodies in neurological practice, as they enable to establish more accurate diagnosis and to better understand the underlying mechanisms of the autoimmune neurological diseases when they are compared to those lacking them. Nevertheless, the exact mechanisms leading to the autoimmune response are still obscure. Genetic predisposition is likely to play a role in autoimmunity, HLA being the most reported genetic factor. Herein, we review the current knowledge about associations between HLA and autoimmune neurological diseases with autoantibodies. We report the main alleles and haplotypes, and discuss the clinical and pathogenic implications of these findings.
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Affiliation(s)
- Sergio Muñiz-Castrillo
- French Reference Center on Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis, Hospices Civils de Lyon, Hôpital Neurologique, 59 Boulevard Pinel, 69677, Bron Cedex, France.,SynatAc Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Alberto Vogrig
- French Reference Center on Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis, Hospices Civils de Lyon, Hôpital Neurologique, 59 Boulevard Pinel, 69677, Bron Cedex, France.,SynatAc Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - Jérôme Honnorat
- French Reference Center on Paraneoplastic Neurological Syndromes and Autoimmune Encephalitis, Hospices Civils de Lyon, Hôpital Neurologique, 59 Boulevard Pinel, 69677, Bron Cedex, France. .,SynatAc Team, Institut NeuroMyoGène, INSERM U1217/CNRS UMR 5310, Université de Lyon, Université Claude Bernard Lyon 1, Lyon, France.
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De Groof TWM, Bobkov V, Heukers R, Smit MJ. Nanobodies: New avenues for imaging, stabilizing and modulating GPCRs. Mol Cell Endocrinol 2019; 484:15-24. [PMID: 30690070 DOI: 10.1016/j.mce.2019.01.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 12/30/2022]
Abstract
The family of G protein-coupled receptors (GPCRs) is the largest class of membrane proteins and an important drug target due to their role in many (patho)physiological processes. Besides small molecules, GPCRs can be targeted by biologicals including antibodies and antibody fragments. This review describes the use of antibodies and in particular antibody fragments from camelid-derived heavy chain-only antibodies (nanobodies/VHHs/sdAbs) for detecting, stabilizing, modulating and therapeutically targeting GPCRs. Altogether, it becomes increasingly clear that the small size, structure and protruding antigen-binding loops of nanobodies are favorable features for the development of selective and potent GPCRs-binding molecules. This makes them attractive tools to modulate GPCR activity but also as targeting modalities for GPCR-directed therapeutics. In addition, these antibody-fragments are important tools in the stabilization of particular conformations of these receptors. Lastly, nanobodies, in contrast to conventional antibodies, can also easily be expressed intracellularly which render nanobodies important tools for studying GPCR function. Hence, GPCR-targeting nanobodies are ideal modalities to image, stabilize and modulate GPCR function.
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Affiliation(s)
- Timo W M De Groof
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Vladimir Bobkov
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands; Argenx BVBA, Industriepark Zwijnaarde 7, 9052, Zwijnaarde, Belgium
| | - Raimond Heukers
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands; QVQ Holding B.V., Yalelaan 1, 3484 CL, Utrecht, the Netherlands
| | - Martine J Smit
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands.
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Abstract
Brain has been considered as an immune-privileged site for centuries owing to the presence of blood-brain barrier, absent lymphatic drainage, and antigen-presenting cells. However, the present prevailing concept is of immune surveillance where brain is continuously surveyed by immune cells. However, the presence of immune cells in central nervous system (CNS) brings the risk of inflammation and autoimmunity involving both T and B cell mediated pathways. These mechanisms form the underlying pathology in a wide spectrum of pediatric CNS diseases manifesting as acquired neurological deficits. Overlapping, heterogenous, and ambiguous clinical features often delays the diagnosis. Although not always pathognomonic, magnetic resonance imaging can be an important biomarker leading to early diagnosis, prognostication, and systematic follow-up pf these diseases. This review describes the spectrum of different pediatric inflammatory disorders and their pertinent imaging features illustrated with clinical examples.
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Affiliation(s)
| | - Karthik Muthusamy
- Department of Neurology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Manohar Shroff
- Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario, Canada
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11
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Liang W, Zhang J, Saint-Martin M, Xu F, Noraz N, Liu J, Honnorat J, Liu H. Structural mapping of hot spots within human CASPR2 discoidin domain for autoantibody recognition. J Autoimmun 2018; 96:168-177. [PMID: 30337146 DOI: 10.1016/j.jaut.2018.09.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 09/23/2018] [Accepted: 09/30/2018] [Indexed: 01/17/2023]
Abstract
Accumulating evidence has showed that anti-CASPR2 autoantibodies occur in a long list of neurological immune disorders including limbic encephalitis (LE). Belonging to the well-known neurexin superfamily, CASPR2 has been suggested to be a central node in the molecular networks controlling neurodevelopment. Distinct from other subfamilies in the neurexin superfamily, the CASPR subfamily features a unique discoidin (Disc) domain. As revealed by our and others' recent studies, CASPR2 Disc domain bears a major epitope for autoantibodies. However, structural information on CASPR2 recognition by autoantibodies has been lacking. Here, we report the crystal structure of human CASPR2 Disc domain at a high resolution of 1.31 Å, which is the first atomic-resolution structure of the CASPR subfamily members. The Disc domain adopts a total β structure and folds into a distorted jellyroll-like barrel with a conserved disulfide-bond interlocking its N- and C-termini. Defined by four loops and located in one end of the barrel, the "loop-tip surface" is totally polar and easily available for protein docking. Based on structure-guided epitope prediction, we generated nine mutants and evaluated their binding to autoantibodies of cerebrospinal fluid from twelve patients with limbic encephalitis. The quadruple mutant G69N/A71S/S77N/D78R impaired CASPR2 binding to autoantibodies from eleven LE patients, which indicates that the loop L1 in the Disc domain bears hot spots for autoantibody interaction. Structural mapping of autoepitopes within human CASPR2 Disc domain sheds light on how autoantibodies could sequester CASPR2 ectodomain and antagonize its functionalities in the pathogenic processes.
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Affiliation(s)
- Wenjun Liang
- State Key Laboratory of Natural and Biomimetic Drugs & School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Junying Zhang
- State Key Laboratory of Natural and Biomimetic Drugs & School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Margaux Saint-Martin
- French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique, Bron, France; INSERM U1217-CNRS UMR5310, NeuroMyoGene Institute, Lyon, France; Université Claude Bernard Lyon 1, Université de Lyon, France
| | - Fei Xu
- State Key Laboratory of Natural and Biomimetic Drugs & School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Nelly Noraz
- French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique, Bron, France; INSERM U1217-CNRS UMR5310, NeuroMyoGene Institute, Lyon, France; Université Claude Bernard Lyon 1, Université de Lyon, France
| | - Jianmei Liu
- State Key Laboratory of Natural and Biomimetic Drugs & School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China
| | - Jérôme Honnorat
- French Reference Center on Paraneoplastic Neurological Syndrome, Hospices Civils de Lyon, Hôpital Neurologique, Bron, France; INSERM U1217-CNRS UMR5310, NeuroMyoGene Institute, Lyon, France; Université Claude Bernard Lyon 1, Université de Lyon, France.
| | - Heli Liu
- State Key Laboratory of Natural and Biomimetic Drugs & School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, 38 Xueyuan Road, Haidian District, Beijing 100191, China.
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12
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Schaefer N, Roemer V, Janzen D, Villmann C. Impaired Glycine Receptor Trafficking in Neurological Diseases. Front Mol Neurosci 2018; 11:291. [PMID: 30186111 PMCID: PMC6110938 DOI: 10.3389/fnmol.2018.00291] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/02/2018] [Indexed: 12/21/2022] Open
Abstract
Ionotropic glycine receptors (GlyRs) enable fast synaptic neurotransmission in the adult spinal cord and brainstem. The inhibitory GlyR is a transmembrane glycine-gated chloride channel. The immature GlyR protein undergoes various processing steps, e.g., folding, assembly, and maturation while traveling from the endoplasmic reticulum to and through the Golgi apparatus, where post-translational modifications, e.g., glycosylation occur. The mature receptors are forward transported via microtubules to the cellular surface and inserted into neuronal membranes followed by synaptic clustering. The normal life cycle of a receptor protein includes further processes like internalization, recycling, and degradation. Defects in GlyR life cycle, e.g., impaired protein maturation and degradation have been demonstrated to underlie pathological mechanisms of various neurological diseases. The neurological disorder startle disease is caused by glycinergic dysfunction mainly due to missense mutations in genes encoding GlyR subunits (GLRA1 and GLRB). In vitro studies have shown that most recessive forms of startle disease are associated with impaired receptor biogenesis. Another neurological disease with a phenotype similar to startle disease is a special form of stiff-person syndrome (SPS), which is most probably due to the development of GlyR autoantibodies. Binding of GlyR autoantibodies leads to enhanced receptor internalization. Here we focus on the normal life cycle of GlyRs concentrating on assembly and maturation, receptor trafficking, post-synaptic integration and clustering, and GlyR internalization/recycling/degradation. Furthermore, this review highlights findings on impairment of these processes under disease conditions such as disturbed neuronal ER-Golgi trafficking as the major pathomechanism for recessive forms of human startle disease. In SPS, enhanced receptor internalization upon autoantibody binding to the GlyR has been shown to underlie the human pathology. In addition, we discuss how the existing mouse models of startle disease increased our current knowledge of GlyR trafficking routes and function. This review further illuminates receptor trafficking of GlyR variants originally identified in startle disease patients and explains changes in the life cycle of GlyRs in patients with SPS with respect to structural and functional consequences at the receptor level.
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Affiliation(s)
- Natascha Schaefer
- Institute for Clinical Neurobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Vera Roemer
- Institute for Clinical Neurobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Dieter Janzen
- Institute for Clinical Neurobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
| | - Carmen Villmann
- Institute for Clinical Neurobiology, Julius-Maximilians-University Würzburg, Würzburg, Germany
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Bechter K. Encephalitis, Mild Encephalitis, Neuroprogression, or Encephalopathy-Not Merely a Question of Terminology. Front Psychiatry 2018; 9:782. [PMID: 30787887 PMCID: PMC6372546 DOI: 10.3389/fpsyt.2018.00782] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/28/2018] [Indexed: 12/17/2022] Open
Abstract
Background: Psychoneuroimmunology research has presented emerging evidence of the involvement of inflammatory and immune mechanisms in the pathogenesis of severe mental disorders. In this context, new terms with increasing clinical relevance have been proposed, challenging the existing terms, and requiring consensus definitions of the new ones. Method: From a perspective of longstanding personal involvement in clinical settings and research in psychoneuroimmunology, the new and the existing terms are critically reconsidered. Results: Meningoencephalitis and encephalitis are comparably well defined clinical terms in neuropsychiatry, although in the individual case approach diagnosis can be difficult, for example in some cases of encephalitis that are described with normal cerebrospinal fluid findings, or often in chronic encephalitis. Encephalopathy is also a widely accepted term, however, with a surprisingly broad meaning with regard to the assigned underlying pathophysiology, ranging from one-hit traumatic encephalopathy to inflammatory encephalopathy, the latter term addressing a type of brain dysfunction secondary to acute systemic inflammation without proven brain autochthonus inflammation (neuroinflammation). However, this latter assumption and term may be wrong as neuroinflammation is difficult to prove in vivo. With emerging insights into prevailing inflammatory and neuroinflammatory mechanisms that are involved in the pathogenesis of severe mental disorders, the interdependent aspects of sensitive assessment and potential clinical relevance of mild neuroinflammation are becoming more apparent and of increasing clinical interest. The new terms "mild encephalitis," "parainflammation," and "neuroprogression" show considerable overlap in addition to gaps and hardly defined borders. However, details are hard to discuss as available studies use many biomarkers, but most of these are done without an established categorical attribution to exclusive terms. Most important, the three new concepts (neruoprogression, parainflammation, and mild encephalitis) are not mutually exclusive, even at the individual case level, and therefore will require state-related individual assessment approaches beyond large confirmatory studies. Conclusion: The newly proposed terms of mild encephalitis, parainflammation, and neuroprogression have an emerging clinical relevance, but respective borders, gaps and overlap in between them remain unclear, and these concepts may even be seen as complementary. Categorical delineation of the new and reconsideration of the existing terms with respect to individualized psychiatric treatment is required for better clinical use, eventually requiring a consensus approach. Here, a critique based on available data and a focus on clinical perspective was outlined, which may help to enhance fruitful discussion. The idea followed here is in line with pillar number six as proposed for the Research Diagnostic Domains, i.e., to provide and follow new concepts in psychiatric research.
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Affiliation(s)
- Karl Bechter
- Department Psychiatry and Psychotherapy II, Bezirkskrankenhaus Günzburg, Ulm University, Ulm, Germany
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Chen CH, Cheng MC, Liu CM, Liu CC, Lin KH, Hwu HG. Seroprevalence survey of selective anti-neuronal autoantibodies in patients with first-episode schizophrenia and chronic schizophrenia. Schizophr Res 2017; 190:28-31. [PMID: 28341002 DOI: 10.1016/j.schres.2017.03.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 03/01/2017] [Accepted: 03/05/2017] [Indexed: 11/17/2022]
Abstract
Autoimmune encephalopathy caused by autoantibodies against neuronal cell-surface proteins in the brain is a newly discovered disease category associated with psychiatric disorders. Correct diagnosis of this condition relies on the detection of specific autoantibodies in the blood or cerebral spinal fluid in addition to the clinical presentations. The study aimed to understand the seroprevalence of selective anti-neuronal autoantibodies in our patients with schizophrenia. First, we screened for six anti-neuronal autoantibodies in an archived blood sample collected from patients with the first-episode schizophrenia. The six autoantibodies including antibodies against N-methyl-d-aspartate (NMDA) receptor, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors 1 and 2, γ-butyric acid receptor type B1 (GABARB1), leucine-rich glioma inactivated-1 (LGI1) protein, and contactin-associated protein-like 2 (CASPR2) protein. A total of 78 plasma samples (46 males and 32 females) were investigated; however, no positive case was identified. In this second study, we screened anti-NMDA receptor autoantibodies in a blood sample of 234 patients with chronic schizophrenia (133 females and 101 males) including 48 patients defined as treatment resistance. None of this sample was detected as positive. The negative findings in this study suggest that the seroprevalence of autoantibodies against neuronal surface proteins might be low in patients diagnosed with schizophrenia.
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Affiliation(s)
- Chia-Hsiang Chen
- Department of Psychiatry, Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan; Department and Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan, Taiwan.
| | - Min-Chih Cheng
- Department of Psychiatry, Yuli Mental Health Research Center, Yuli Branch, Taipei Veterans General Hospital, Hualien, Taiwan
| | - Chih-Min Liu
- Department of Psychiatry, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Graduate Institute of Brain and Mind Sciences, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chen-Chung Liu
- Department of Psychiatry, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Ko-Huan Lin
- Department of Psychiatry, Hualien Armed Forces General Hospital, Hualien, Taiwan
| | - Hai-Gwo Hwu
- Department of Psychiatry, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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Shin YW, Lee ST, Park KI, Jung KH, Jung KY, Lee SK, Chu K. Treatment strategies for autoimmune encephalitis. Ther Adv Neurol Disord 2017; 11:1756285617722347. [PMID: 29399043 PMCID: PMC5784571 DOI: 10.1177/1756285617722347] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 06/14/2017] [Indexed: 12/13/2022] Open
Abstract
Autoimmune encephalitis is one of the most rapidly growing research topics in neurology. Along with discoveries of novel antibodies associated with the disease, clinical experience and outcomes with diverse immunotherapeutic agents in the treatment of autoimmune encephalitis are accumulating. Retrospective observations indicate that early aggressive treatment is associated with better functional outcomes and fewer relapses. Immune response to first-line immunotherapeutic agents (corticosteroids, intravenous immunoglobulin, plasma exchange, and immunoadsorption) is fair, but approximately half or more of patients are administered second-line immunotherapy (rituximab and cyclophosphamide). A small but significant proportion of patients are refractory to all first- and second-line therapies and require further treatment. Although several investigations have shown promising alternatives, the low absolute number of patients involved necessitates more evidence to establish further treatment strategies. In this review, the agents used for first- and second-line immunotherapy are discussed and recent attempts at finding new treatment options are introduced.
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Affiliation(s)
- Yong-Won Shin
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, South Korea Yeongjusi Health Center, Gyeongsangbuk-do, South Korea
| | - Soon-Tae Lee
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, South Korea
| | - Kyung-Il Park
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, South Korea
| | - Keun-Hwa Jung
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, South Korea
| | - Ki-Young Jung
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, South Korea
| | - Sang Kun Lee
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National University Hospital, Seoul, South Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, South Korea
| | - Kon Chu
- Department of Neurology, Comprehensive Epilepsy Center, Laboratory for Neurotherapeutics, Biomedical Research Institute, Seoul National niversity Hospital, 101, Daehangno, Jongno-gu, Seoul 110-744, South Korea Program in Neuroscience, Seoul National University College of Medicine, Seoul, South Korea
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Do LD, Chanson E, Desestret V, Joubert B, Ducray F, Brugière S, Couté Y, Formaglio M, Rogemond V, Thomas-Antérion C, Borrega L, Laurens B, Tison F, Curot J, De Brouker T, Lebrun-Frenay C, Delattre JY, Antoine JC, Honnorat J. Characteristics in limbic encephalitis with anti–adenylate kinase 5 autoantibodies. Neurology 2017; 88:514-524. [DOI: 10.1212/wnl.0000000000003586] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 09/26/2016] [Indexed: 11/15/2022] Open
Abstract
Objective:To report 10 patients with limbic encephalitis (LE) and adenylate kinase 5 autoantibodies (AK5-Abs).Methods:We conducted a retrospective study in a cohort of 50 patients with LE with uncharacterized autoantibodies and identified a specific target using immunohistochemistry, Western blotting, immunoprecipitation, mass spectrometry, and cell-based assay.Results:AK5 (a known autoantigen of LE) was identified as the target of antibodies in the CSFs and sera of 10 patients with LE (median age 64 years; range 57–80), which was characterized by subacute anterograde amnesia without seizure and sometimes preceded by a prodromal phase of asthenia or mood disturbances. Anterograde amnesia can be isolated, but some patients also complained of prosopagnosia, paroxysmal anxiety, or abnormal behavior. No associated cancer was observed. All 10 patients had bilateral hippocampal hypersignal on a brain MRI. CSF analysis generally showed a mild pleiocytosis with elevated immunoglobulin G index and oligoclonal bands, as well as high levels of tau protein with normal concentration of Aβ42 and phospho-tau, suggesting a process of neuronal death. Except for one patient, clinical response to immunotherapy was unfavorable, with persistence of severe anterograde amnesia. Two patients evolved to severe cognitive decline. Hippocampal atrophy was observed on control brain MRI. Using in vitro tests on hippocampal neurons, we did not identify clues suggesting a direct pathogenic role of AK5-Abs.Conclusions:AK5-Abs should be systematically considered in aged patients with subacute anterograde amnesia. Recognition of this disorder is important to develop new treatment strategies to prevent irreversible limbic damage.
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