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Gaig C, Sabater L. New knowledge on anti-IgLON5 disease. Curr Opin Neurol 2024; 37:316-321. [PMID: 38563128 PMCID: PMC11064895 DOI: 10.1097/wco.0000000000001271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
PURPOSE OF REVIEW Anti-IgLON5 disease is characterized by a distinctive sleep disorder, associated with a heterogeneous spectrum of neurological symptoms. Initial autopsies showed a novel neuronal tauopathy predominantly located in the tegmentum of the brainstem. Recently, new diagnostic red flags, biomarkers predictors of response to immunotherapy, and novel insights into the autoimmune pathogenesis of the disease have been reported. RECENT FINDINGS Patients with diagnosis of neurodegenerative dementia, progressive supranuclear palsy (PSP) or with motor-neuron disease (MND)-like syndrome have been reported to have IgLON5 antibodies, which are the hallmark of anti-IgLON5 disease. Second, low levels of neurofilament light chain in serum and cerebrospinal fluid of patients at disease onset could be a predictor of immunotherapy response. Recent neuropathological studies indicate that the neuronal tau deposits occur late in the course of the disease. Moreover, IgLON5 antibodies induce cytoskeletal changes in cultured hippocampal neurons suggesting that the tauopathy could be secondary of the IgLON5 antibody effects. SUMMARY Anti-IgLON5 disease can mimic and should be considered in atypical presentations of MND, neurodegenerative dementia and PSP. Neurofilament light chain levels seem promising biomarker for disease prognosis. Finally, the neuropathological and in vitro experimental studies strengthen the autoimmune hypothesis of the disease.
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Affiliation(s)
- Carles Gaig
- Service of Neurology, Hospital Clinic de Barcelona
| | - Lidia Sabater
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d’Investigacions Biomèdiques August Pi i Sunyer, Universitat de Barcelona, Barcelona, Spain
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Papi C, Milano C, Spatola M. Mechanisms of autoimmune encephalitis. Curr Opin Neurol 2024; 37:305-315. [PMID: 38667756 DOI: 10.1097/wco.0000000000001270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2024]
Abstract
PURPOSE OF REVIEW To provide an overview of the pathogenic mechanisms involved in autoimmune encephalitides mediated by antibodies against neuronal surface antigens, with a focus on NMDAR and LGI1 encephalitis. RECENT FINDINGS In antibody-mediated encephalitides, binding of IgG antibodies to neuronal surface antigens results in different pathogenic effects depending on the type of antibody, IgG subclass and epitope specificity. NMDAR IgG1 antibodies cause crosslinking and internalization of the target, synaptic and brain circuitry alterations, as well as alterations of NMDAR expressing oligodendrocytes, suggesting a link with white matter lesions observed in MRI studies. LGI1 IgG4 antibodies, instead, induce neuronal dysfunction by disrupting the interaction with cognate proteins and altering AMPAR-mediated signaling. In-vitro findings have been corroborated by memory and behavioral changes in animal models obtained by passive transfer of patients' antibodies or active immunization. These models have been fundamental to identify targets for innovative therapeutic strategies, aimed at counteracting or preventing antibody effects, such as the use of soluble ephrin-B2, NMDAR modulators (e.g., pregnenolone, SGE-301) or chimeric autoantibody receptor T cells (CAART) in models of NMDAR encephalitis. SUMMARY A deep understanding of the pathogenic mechanisms underlying antibody-mediated encephalitides is crucial for the development of new therapeutic approaches targeting brain autoimmunity.
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Affiliation(s)
- Claudia Papi
- Department of Neuroscience, Catholic University of the Sacred Heart, Rome, Italy
- Fundació Recerca Biomedica Clinic - Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRBC-IDIBAPS), Barcelona, Spain
| | - Chiara Milano
- Fundació Recerca Biomedica Clinic - Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRBC-IDIBAPS), Barcelona, Spain
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Marianna Spatola
- Fundació Recerca Biomedica Clinic - Institut d'Investigacions Biomèdiques August Pi i Sunyer (FRBC-IDIBAPS), Barcelona, Spain
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Landa J, Serafim AB, Alba M, Maudes E, Molina-Porcel L, Garcia-Serra A, Mannara F, Dalmau J, Graus F, Sabater L. IgLON5 deficiency produces behavioral alterations in a knockout mouse model. Front Immunol 2024; 15:1347948. [PMID: 38370417 PMCID: PMC10869603 DOI: 10.3389/fimmu.2024.1347948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/09/2024] [Indexed: 02/20/2024] Open
Abstract
Background Anti-IgLON5 disease is a neurological disorder characterized by autoantibodies against IgLON5 and pathological evidence of neurodegeneration. IgLON5 is a cell adhesion molecule of unknown function that is highly expressed in the brain. Our aim was to investigate the impact of IgLON5 loss-of-function in evaluating brain morphology, social behavior, and the development of symptoms observed in an IgLON5 knockout (IgLON5-KO) mouse model. Methods The IgLON5-KO mice were generated using CRISPR-Cas9 technology. Immunohistochemistry on fixed sagittal brain sections and Western blotting brain lysates were used to confirm IgLON5 silencing and to evaluate the presence of other cell surface proteins. Two- month-old IgLON5-KO and wild-type (WT) mice underwent a comprehensive battery of behavioral tests to assess 1) locomotion, 2) memory, 3) anxiety, 4) social interaction, and 5) depressive-like behavior. Brain sections were examined for the presence of anatomical abnormalities and deposits of hyperphosphorylated tau in young adult (2-month-old) and aged (22-month-old) mice. Results Mice did not develop neurological symptoms reminiscent of those seen in patients with anti-IgLON5 disease. Behavioral testing revealed that 2-month-old IgLON5-KO mice showed subtle alterations in motor coordination and balance. IgLON5-KO females exhibited hyperactivity during night and day. Males were observed to have depressive-like behavior and excessive nest-building behavior. Neuropathological studies did not reveal brain morphological alterations or hyperphosphorylated tau deposits. Conclusion IgLON5-KO mice showed subtle alterations in behavior and deficits in fine motor coordination but did not develop the clinical phenotype of anti-IgLON5 disease.
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Affiliation(s)
- Jon Landa
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
| | - Ana Beatriz Serafim
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
| | - Mercedes Alba
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
| | - Estibaliz Maudes
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
| | - Laura Molina-Porcel
- Alzheimer’s Disease and Other Cognitive Disorders Unit, Neurology Service, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Neurological Tissue Bank, Biobanc, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Anna Garcia-Serra
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
| | - Francesco Mannara
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
| | - Josep Dalmau
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
- Centro de Investigación Biomédica en Red, Enfermedades Raras (CIBERER), Madrid, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Francesc Graus
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
| | - Lidia Sabater
- Neuroimmunology Program, Fundació de Recerca Clínic Barcelona-Institut d'Investigacions Biomédiques August Pi i Sunyer-Caixa Research Institute (CRI), Universitat de Barcelona, Barcelona, Spain
- Centro de Investigación Biomédica en Red, Enfermedades Raras (CIBERER), Madrid, Spain
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Ryding M, Mikkelsen AW, Nissen MS, Nilsson AC, Blaabjerg M. Pathophysiological Effects of Autoantibodies in Autoimmune Encephalitides. Cells 2023; 13:15. [PMID: 38201219 PMCID: PMC10778077 DOI: 10.3390/cells13010015] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
The heterogeneity of autoantibody targets in autoimmune encephalitides presents a challenge for understanding cellular and humoral pathophysiology, and the development of new treatment strategies. Thus, current treatment aims at autoantibody removal and immunosuppression, and is primarily based on data generated from other autoimmune neurological diseases and expert consensus. There are many subtypes of autoimmune encephalitides, which now entails both diseases with autoantibodies targeting extracellular antigens and classical paraneoplastic syndromes with autoantibodies targeting intracellular antigens. Here, we review the current knowledge of molecular and cellular effects of autoantibodies associated with autoimmune encephalitis, and evaluate the evidence behind the proposed pathophysiological mechanisms of autoantibodies in autoimmune encephalitis.
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Affiliation(s)
- Matias Ryding
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark;
- Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
| | - Anne With Mikkelsen
- Department of Clinical Immunology, Odense University Hospital, 5000 Odense, Denmark;
| | | | - Anna Christine Nilsson
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark;
- Department of Clinical Immunology, Odense University Hospital, 5000 Odense, Denmark;
| | - Morten Blaabjerg
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark;
- Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
- Department of Neurology, Odense University Hospital, 5000 Odense, Denmark;
- Brain Research—Inter Disciplinary Guided Excellence (BRIDGE), 5000 Odense, Denmark
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Bartsch T, Berg D, Heneka M, Leypoldt F. [Parkinson's and Alzheimer's disease as system-wide neurodegenerative disorders]. DER NERVENARZT 2023; 94:875-884. [PMID: 37672086 DOI: 10.1007/s00115-023-01542-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/25/2023] [Indexed: 09/07/2023]
Abstract
BACKGROUND Parkinson's and Alzheimer's disease (PD/AD) are characterized by cellular pathological changes that precede clinical manifestation and symptom onset by decades (prodromal period) as well as by a heterogeneity of clinical symptoms. Both diseases are recognized as system-wide diseases with organ-transgressing dysregulation and involvement of immunological and neuroinflammatory mechanisms facilitating pathological protein aggregation and neurodegeneration. OBJECTIVES Overview of natural course, phenotypes and classification of PD/AD with a focus on underlying (system-wide) immunological and neuroinflammatory mechanisms. METHODS Literature research and consideration of expert opinions. RESULTS The accumulation of misfolded proteins such as amyloid‑β and synuclein in the course of neurodegenerative processes forms the basis of the current biological classifications, understanding of course and subtypes. Protein aggregation in PD/AD induces an innate immune response by activating microglia and the release of inflammatory mediators such as cytokines and chemokines and leading to further spread of neurodegeneration and accumulation of intracellular neurofibrillary tangles (NFTs). There is also growing evidence that adaptive immune responses involving auto-antibodies or auto-antigen-specific T‑/B-cell reactions involving tau, amyloid‑β or synuclein might be involved in the disease progression or subtypes of PD/AD. CONCLUSIONS Both innate and adaptive immune responses seem to be substantially involved in the pathological cascade leading to neurodegeneration in PD/AD and may contribute to disease progression and clinical subtypes. Thus, future targeted interventions should not only focus on protein aggregation but also on neuroinflammatory and immunological mechanisms.
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Affiliation(s)
- Thorsten Bartsch
- Klinik für Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Deutschland.
- Klinik für Neurologie, AG Gedächtnis und Plastizität, Gedächtnis- und Demenzsprechstunde, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Arnold-Heller-Str. 3, 24105, Kiel, Deutschland.
| | - Daniela Berg
- Klinik für Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Deutschland
| | - Michael Heneka
- Luxembourg Centre for Systems Biomedicine, Université du Luxembourg, Belvaux, Luxemburg
| | - Frank Leypoldt
- Klinik für Neurologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Kiel, Deutschland
- Institut für Klinische Chemie, Universitätsklinikum Schleswig-Holstein, Campus Kiel und Lübeck, Kiel, Deutschland
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Zhang YZ, Ni Y, Gao YN, Shen DD, He L, Yin D, Meng HY, Zhou QM, Hu J, Chen S. Anti-IgLON5 disease: a novel topic beyond neuroimmunology. Neural Regen Res 2022; 18:1017-1022. [PMID: 36254983 PMCID: PMC9827781 DOI: 10.4103/1673-5374.355742] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Anti-IgLON5 disease is a recently defined autoimmune disorder of the nervous system associated with autoantibodies against IgLON5. Given its broad clinical spectrum and extremely complex pathogenesis, as well as difficulties in its early diagnosis and treatment, anti-IgLON5 disease has become the subject of considerable research attention in the field of neuroimmunology. Anti-IgLON5 disease has characteristics of both autoimmunity and neurodegeneration due to the unique activity of the anti-IgLON5 antibody. Neuropathologic examination revealed the presence of a tauopathy preferentially affecting the hypothalamus and brainstem tegmentum, potentially broadening our understanding of tauopathies. In contrast to that seen with other autoimmune encephalitis-related antibodies, basic studies have demonstrated that IgLON5 antibody-induced neuronal damage and degeneration are irreversible, indicative of a potential link between autoimmunity and neurodegeneration in anti-IgLON5 disease. Herein, we comprehensively review and discuss basic and clinical studies relating to anti-IgLON5 disease to better understand this complicated disorder.
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Affiliation(s)
- Yi-ZongHeng Zhang
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - You Ni
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yi-Ning Gao
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ding-Ding Shen
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Lu He
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Dou Yin
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Huan-Yu Meng
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qin-Ming Zhou
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China,Correspondence to: Sheng Chen, ; Ji Hu, ; Qin-Ming Zhou, .
| | - Ji Hu
- Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China,School of Life Science and Technology, ShanghaiTech University, Shanghai, China,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai, China,Correspondence to: Sheng Chen, ; Ji Hu, ; Qin-Ming Zhou, .
| | - Sheng Chen
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, China,Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China,Correspondence to: Sheng Chen, ; Ji Hu, ; Qin-Ming Zhou, .
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