401
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402
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The role of antibodies in multiple sclerosis. Biochim Biophys Acta Mol Basis Dis 2011; 1812:239-45. [DOI: 10.1016/j.bbadis.2010.06.009] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2009] [Revised: 06/11/2010] [Accepted: 06/16/2010] [Indexed: 11/23/2022]
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403
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404
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405
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Li L, Zhang H, Varrin-Doyer M, Zamvil SS, Verkman AS. Proinflammatory role of aquaporin-4 in autoimmune neuroinflammation. FASEB J 2011; 25:1556-66. [PMID: 21257712 DOI: 10.1096/fj.10-177279] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Aquaporin-4 (AQP4) deficiency in mice reduces neuroinflammation in experimental autoimmune encephalomyelitis (EAE) produced by active immunization with myelin oligodendrocyte glycoprotein peptide (MOG). Potential mechanisms for the protective effect of AQP4 deficiency were investigated, including AQP4-dependent leukocyte and microglia cell function, immune cell entry in the central nervous system (CNS), intrinsic neuroinflammation, and humoral immune response. As we found with active-immunization EAE, neuroinflammation was greatly reduced in AQP4-knockout mice in adoptive-transfer EAE. AQP4 was absent in immune cells, including activated T lymphocytes. The CNS migration of fluorescently labeled, MOG-sensitized T lymphocytes was comparable in wild-type and AQP4-knockout mice. Microglia did not express AQP4. Serum anti-AQP4 antibodies were absent in EAE. Remarkably, intracerebral injection of LPS produced much greater neuroinflammation in wild-type than in AQP4-knockout mice, and cytokine (TNF-α and IL-6) secretion was reduced in astrocyte cultures from AQP4-knockout mice. Adenovirus-mediated expression of AQP4, or of an unrelated aquaporin, AQP1, increased cytokine secretion in astrocyte and nonastrocyte cell cultures, supporting the involvement of aquaporin water permeability in cytokine secretion. Our data suggest an intrinsic proinflammatory role of AQP4 involving AQP4-dependent astrocyte swelling and cytokine release. Reduction in AQP4 water transport may be protective in neuroinflammatory CNS diseases.
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Affiliation(s)
- Lihua Li
- Department of Medicine, University of California, San Francisco, California 94143-0521, USA
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406
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Functional characterization of aquaporin-4 specific T cells: towards a model for neuromyelitis optica. PLoS One 2011; 6:e16083. [PMID: 21264240 PMCID: PMC3021520 DOI: 10.1371/journal.pone.0016083] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 12/09/2010] [Indexed: 12/05/2022] Open
Abstract
Background Antibodies to the water channel protein aquaporin-4 (AQP4), which is expressed in astrocytic endfeet at the blood brain barrier, have been identified in the serum of Neuromyelitis optica (NMO) patients and are believed to induce damage to astrocytes. However, AQP4 specific T helper cell responses that are required for the generation of anti-AQP4 antibodies and most likely also for the formation of intraparenchymal CNS lesions have not been characterized. Methodology/Principal Findings Using overlapping 15-meric peptides of AQP4, we identified the immunogenic T cell epitopes of AQP4 that are restricted to murine major histocompatibility complex (MHC) I-Ab. The N-terminal region of AQP4 was highly immunogenic. More precisely, the intracellular epitope AQP422–36 was detected as major immunogenic determinant. AQP482–108 (located in the second transmembrane domain), AQP4139–153 (located in the second extracellular loop), AQP4211–225 (located in the fifth transmembrane domain), AQP4235–249 (located in the sixth transmembrane domain), as well as AQP4289–306 in the intracellular C-terminal region were also immunogenic epitopes. AQP422–36 and AQP4289–303 specific T cells were present in the natural T cell repertoire of wild type C57BL/6 mice and T cell lines were raised. However, active immunization with these AQP4 peptides did not induce signs of spinal cord disease. Rather, sensitization with AQP4 peptides resulted in production of IFN-γ, but also IL-5 and IL-10 by antigen-specific T cells. Consistent with this cytokine profile, the AQP4 specific antibody response upon immunization with full length AQP4 included IgG1 and IgG2, which are associated with a mixed Th2/Th1 T cell response. Conclusions and Significance AQP4 is able to induce an autoreactive T cell response. The identification of I-Ab restricted AQP4 specific T cell epitopes will allow us to investigate how AQP4 specific autoimmune reactions are regulated and to establish faithful mouse models of NMO that include both cellular and humoral responses against AQP4.
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407
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Yu X, Gilden D, Schambers L, Barmina O, Burgoon M, Bennett J, Owens G. Peptide reactivity between multiple sclerosis (MS) CSF IgG and recombinant antibodies generated from clonally expanded plasma cells in MS CSF. J Neuroimmunol 2010; 233:192-203. [PMID: 21176973 DOI: 10.1016/j.jneuroim.2010.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2010] [Revised: 11/03/2010] [Accepted: 11/16/2010] [Indexed: 01/25/2023]
Abstract
We employed 19 recombinant antibodies (rAbs) generated from clonally expanded plasma cells, and native IgG from cerebrospinal fluid (CSF) of three multiple sclerosis (MS) patients for panning with phage displayed random peptide libraries. Specific peptide epitopes/mimotopes were identified and characterized. Importantly, peptide-antibody interactions were shared by rAbs and native IgG from the same patient. Three peptides strongly interacted with at least one other MS CSF, but not to inflammatory CNS controls. Database searches revealed several protein candidates including stress proteins, cell surface proteins, and neuronal proteins. Peptides derived from the candidate proteins were recognized by rAbs. Identification of peptide epitopes/mimotopes in MS may provide clues regarding disease-relevant antigens.
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Affiliation(s)
- Xiaoli Yu
- Department of Neurology, University of Colorado Denver at Anschutz Medical Campus, 12700 E. 19th Ave., Aurora, CO 80045, United States.
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408
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Abstract
PURPOSE OF REVIEW Inflammatory and auto-immune disorders of the central nervous system are a heterogeneous group of disorders. Many of these disorders are potentially treatable with immune therapies that can reduce disability or prevent death. We review the clinical value of biomarkers which can aid in the diagnosis of paediatric inflammatory and auto-immune central nervous system (CNS) disorders. RECENT FINDINGS This review will first describe the clinical usefulness of nonspecific biomarkers of CNS inflammation such as cerebrospinal fluid neopterin and oligoclonal bands. Neopterin is produced by immune and neuronal cells after stimulation by interferon species and is increased in a broad range of inflammatory and auto-immune CNS disorders. Oligoclonal bands represent clonal production of immunoglobulin G in the CNS and are present in demyelinating, auto-immune, and infectious CNS disorders. In addition, we will review new advances in the immunogenetic investigation of familial auto-inflammatory disorders such as Aicardi-Goutières syndrome and Chronic Infantile Neurologic Cutaneous Articular syndrome. Finally, we will review the clinical utility of auto-antibodies in CNS disorders, with specific focus on auto-antibodies that bind to cell surface proteins such as N-methyl-D-asparate receptor, voltage-gated potassium channels, myelin oligodendrocyte glycoprotein, and aquaporin-4. SUMMARY These biomarkers are increasingly important in the recognition and treatment of inflammatory and auto-immune CNS disorders. Like many biomarkers in paediatric practice, it is essential to interpret the findings in the context of the patient history and examination.
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409
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Nelson PA, Khodadoust M, Prodhomme T, Spencer C, Patarroyo JC, Varrin-Doyer M, Ho JD, Stroud RM, Zamvil SS. Immunodominant T cell determinants of aquaporin-4, the autoantigen associated with neuromyelitis optica. PLoS One 2010; 5:e15050. [PMID: 21151500 PMCID: PMC2994828 DOI: 10.1371/journal.pone.0015050] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 10/14/2010] [Indexed: 01/02/2023] Open
Abstract
Autoantibodies that target the water channel aquaporin-4 (AQP4) in neuromyelitis optica (NMO) are IgG1, a T cell-dependent Ig subclass. However, a role for AQP4-specific T cells in this CNS inflammatory disease is not known. To evaluate their potential role in CNS autoimmunity, we have identified and characterized T cells that respond to AQP4 in C57BL/6 and SJL/J mice, two strains that are commonly studied in models of CNS inflammatory diseases. Mice were immunized with either overlapping peptides or intact hAQP4 protein encompassing the entire 323 amino acid sequence. T cell determinants identified from examination of the AQP4 peptide (p) library were located within AQP4 p21-40, p91-110, p101-120, p166-180, p231-250 and p261-280 in C57BL/6 mice, and within p11-30, p21-40, p101-120, p126-140 and p261-280 in SJL/J mice. AQP4-specific T cells were CD4+ and MHC II-restricted. In recall responses to immunization with intact AQP4, T cells responded primarily to p21-40, indicating this region contains the immunodominant T cell epitope(s) for both strains. AQP4 p21-40-primed T cells secreted both IFN-γ and IL-17. The core immunodominant AQP4 21-40 T cell determinant was mapped to residues 24-35 in C57BL/6 mice and 23-35 in SJL/J mice. Our identification of the AQP4 T cell determinants and characterization of its immunodominant determinant should permit investigators to evaluate the role of AQP4-specific T cells in vivo and to develop AQP4-targeted murine NMO models.
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Affiliation(s)
- Patricia A. Nelson
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Mojgan Khodadoust
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Thomas Prodhomme
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Collin Spencer
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Juan Carlos Patarroyo
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Michel Varrin-Doyer
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
| | - Joseph D. Ho
- Department of Biochemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Robert M. Stroud
- Department of Biochemistry, University of California San Francisco, San Francisco, California, United States of America
| | - Scott S. Zamvil
- Department of Neurology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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410
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Vincent A. Successful 'passive transfer' of paraneoplastic stiff person syndrome with antibodies to an intracellular antigen. Brain 2010; 133:3164-5. [PMID: 21030432 DOI: 10.1093/brain/awq302] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Affiliation(s)
- Angela Vincent
- Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
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411
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Intra-axial pseudotumors in the central nervous system: clinicopathological analysis. Brain Tumor Pathol 2010; 27:71-80. [PMID: 21046308 DOI: 10.1007/s10014-010-0266-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 03/02/2010] [Indexed: 10/18/2022]
Abstract
Intra-axial pseudotumors in the central nervous system often mimic malignant brain tumors and cause difficulty in diagnosis and treatment. The present study investigates their radiologic and histological features to elucidate diagnostic clues. Six cases were included in the study, one man and five women, ranging in age from 44 to 87 years (mean age, 61 years). Histologically, three cases had demyelination, and one case each had abscess, angiitis, and non-Langerhans cell histiocytosis. All cases were evaluated radiologically on MRI, most of them by thallim-201 single photon emission tomography ((201)Tl-SPECT). These cases were examined using H&E, special stains, and immunohistochemical studies with a variety of antibodies. MRI demonstrated perifocal edema and ring-like or solid enhancement, mimicking the malignant tumors. Diffusion-weighted MRI showed a hypo-iso-intensity with a hyperintensity on the apparent diffusion coefficient. A (201)Tl-SPECT study revealed no uptake. Although there were various kinds of pathology, inflammatory cells were observed, associated with vascular proliferation and reactive astrocytosis. In addition, some cases showed demyelinating or destructive changes. These results suggested that intra-axial pseudotumors in the central nervous system contain various kinds of pathology, and detailed clinicopathological analysis is important from the point of view of differential diagnosis.
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412
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Aquaporin-4 astrocytopathy in Baló's disease. Acta Neuropathol 2010; 120:651-60. [PMID: 20680636 DOI: 10.1007/s00401-010-0733-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Revised: 07/22/2010] [Accepted: 07/27/2010] [Indexed: 12/26/2022]
Abstract
Baló's concentric sclerosis (BCS) is considered to be a rare variant of multiple sclerosis and characterized by alternating rings of demyelinated and preserved myelin layers. The mechanism underlying BCS remains to be elucidated. Recently, occurrence of concentric rings of Baló was described in the brainstem of a patient with neuromyelitis optica (NMO). Because selective loss of aquaporin-4 (AQP4) and vasculocentric deposition of complement and immunoglobulins are characteristic in NMO, we aimed to assess AQP4 expression in the concentric demyelinating lesions of BCS patients. We evaluated AQP4 expression relative to expression of another astrocytic marker (glial fibrillary acidic protein), the extent of demyelination, lesion staging and perivascular deposition of complement and immunoglobulin in four cases with BCS, and 30 individuals with other neurological diseases. All cases with BCS demonstrated extensive AQP4 loss in both demyelinated and myelinated layers of all actively demyelinating lesions, with perivascular lymphocytic cuffing of T cells, but no deposition of immunoglobulins or complement around vessels. These findings suggest that AQP4 loss occurs in heterogeneous demyelinating conditions, namely NMO and BCS. Furthermore, acute BCS lesions are characterized by extensive AQP4 loss without vasculocentric deposition of complement or immunoglobulin.
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413
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Vincent A. Autoimmune channelopathies: well-established and emerging immunotherapy-responsive diseases of the peripheral and central nervous systems. J Clin Immunol 2010; 30 Suppl 1:S97-102. [PMID: 20387102 DOI: 10.1007/s10875-010-9401-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND The role of antibodies in neuromuscular junction disorders is well established with antibodies to acetylcholine receptor, muscle-specific kinase, and voltage-gated calcium channels. The diseases associated with these antibodies, myasthenia gravis and the Lambert-Eaton myasthenic syndrome, respond well to symptomatic treatments (e.g., cholinesterase inhibitors) and to immunotherapies such as plasma exchange, intravenous immunoglobulin, oral steroids, and steroid-sparing drugs. The role of the antibodies has been established by a variety of in vitro and in vivo approaches. More recently, antibodies to voltage-gated potassium channels have been identified in patients with autoimmune forms of acquired neuromyotonia. Over the last decade, antibodies to CNS membrane receptors or ion channels have begun to be identified and these antibodies define antibody-mediated CNS diseases that also respond to immunotherapies. SUMMARY The paradigms gained from the study of the peripheral conditions has led to a better appreciation of the role of antibodies in neurological disorders and a growing recognition of their role in central nervous system (CNS) diseases.
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Affiliation(s)
- Angela Vincent
- Department of Clinical Neurology, Level 6 West Wing, John Radcliffe Hospital, University of Oxford, Oxford, UK.
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414
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Frequency and prognostic impact of antibodies to aquaporin-4 in patients with optic neuritis. J Neurol Sci 2010; 298:158-62. [DOI: 10.1016/j.jns.2010.07.011] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 07/15/2010] [Accepted: 07/21/2010] [Indexed: 10/19/2022]
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415
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Sellner J, Cepok S, Kalluri SR, Nestler A, Kleiter I, Kümpfel T, Linker R, Melms A, Menge T, Tumani H, Paul F, Hemmer B, Berthele A. Aquaporin 4 antibody positive central nervous system autoimmunity and multiple sclerosis are characterized by a distinct profile of antibodies to herpes viruses. Neurochem Int 2010; 57:662-7. [DOI: 10.1016/j.neuint.2010.08.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 07/22/2010] [Accepted: 08/03/2010] [Indexed: 12/15/2022]
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416
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Abstract
Antibodies to aquaporin-4 (also known as AQP4-Ab or NMO-IgG) are sensitive and highly specific serum markers of autoimmune neuromyelitis optica (NMO). Second-generation recombinant diagnostic assays can detect AQP4-Ab in >or=80% of patients with NMO, and a role for AQP4-Ab in the pathophysiology of this condition was corroborated by a series of in vitro studies that demonstrated disruption of the blood-brain barrier, impairment of glutamate homeostasis and induction of necrotic cell death by AQP4-Ab-positive serum. Additional evidence for such a role has emerged from clinical observations, including the demonstration of a correlation between serum levels of AQP4-Ab and disease activity. The finding of NMO-like CNS lesions and clinical disease following passive transfer of AQP4-Ab-positive serum in several independent animal studies provided definitive proof for a pathogenic role of AQP4-Ab in vivo. Together, these findings provide a strong rationale for the use of therapies targeted against B cells or antibodies in the treatment of NMO. In this Review, we summarize the latest evidence in support of a direct involvement of AQP4-Ab in the immunopathogenesis of NMO, and critically appraise the diagnostic tests currently available for the detection of this serum reactivity.
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417
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Geis C, Weishaupt A, Hallermann S, Grünewald B, Wessig C, Wultsch T, Reif A, Byts N, Beck M, Jablonka S, Boettger MK, Üçeyler N, Fouquet W, Gerlach M, Meinck HM, Sirén AL, Sigrist SJ, Toyka KV, Heckmann M, Sommer C. Stiff person syndrome-associated autoantibodies to amphiphysin mediate reduced GABAergic inhibition. ACTA ACUST UNITED AC 2010; 133:3166-80. [PMID: 20884644 DOI: 10.1093/brain/awq253] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Synaptic inhibition is a central factor in the fine tuning of neuronal activity in the central nervous system. Symptoms consistent with reduced inhibition such as stiffness, spasms and anxiety occur in paraneoplastic stiff person syndrome with autoantibodies against the intracellular synaptic protein amphiphysin. Here we show that intrathecal application of purified anti-amphiphysin immunoglobulin G antibodies induces stiff person syndrome-like symptoms in rats, including stiffness and muscle spasms. Using in vivo recordings of Hoffmann reflexes and dorsal root potentials, we identified reduced presynaptic GABAergic inhibition as an underlying mechanism. Anti-amphiphysin immunoglobulin G was internalized into neurons by an epitope-specific mechanism and colocalized in vivo with presynaptic vesicular proteins, as shown by stimulation emission depletion microscopy. Neurons from amphiphysin deficient mice that did not internalize the immunoglobulin provided additional evidence of the specificity in antibody uptake. GABAergic synapses appeared more vulnerable than glutamatergic synapses to defective endocytosis induced by anti-amphiphysin immunoglobulin G, as shown by increased clustering of the endocytic protein AP180 and by defective loading of FM 1-43, a styryl dye used to label cell membranes. Incubation of cultured neurons with anti-amphiphysin immunoglobulin G reduced basal and stimulated release of γ-aminobutyric acid substantially more than that of glutamate. By whole-cell patch-clamp analysis of GABAergic inhibitory transmission in hippocampus granule cells we showed a faster, activity-dependent decrease of the amplitude of evoked inhibitory postsynaptic currents in brain slices treated with antibodies against amphiphysin. We suggest that these findings may explain the pathophysiology of the core signs of stiff person syndrome at the molecular level and show that autoantibodies can alter the function of inhibitory synapses in vivo upon binding to an intraneuronal key protein by disturbing vesicular endocytosis.
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Affiliation(s)
- Christian Geis
- Department of Neurology, University of Würzburg, Josef-Schneider-Str. 11, 97080 Würzburg, Germany
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418
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Weber MS, Prod'homme T, Patarroyo JC, Molnarfi N, Karnezis T, Lehmann-Horn K, Danilenko DM, Eastham-Anderson J, Slavin AJ, Linington C, Bernard CCA, Martin F, Zamvil SS. B-cell activation influences T-cell polarization and outcome of anti-CD20 B-cell depletion in central nervous system autoimmunity. Ann Neurol 2010; 68:369-83. [PMID: 20641064 DOI: 10.1002/ana.22081] [Citation(s) in RCA: 232] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Clinical studies indicate that anti-CD20 B-cell depletion may be an effective multiple sclerosis (MS) therapy. We investigated mechanisms of anti-CD20-mediated immune modulation using 2 paradigms of experimental autoimmune encephalomyelitis (EAE). METHODS Murine EAE was induced by recombinant myelin oligodendrocyte glycoprotein (rMOG), a model in which B cells are considered to contribute pathogenically, or MOG peptide (p)35-55, which does not require B cells. RESULTS In EAE induced by rMOG, B cells became activated and, when serving as antigen-presenting cells (APCs), promoted differentiation of proinflammatory MOG-specific Th1 and Th17 cells. B-cell depletion prevented or reversed established rMOG-induced EAE, which was associated with less central nervous system (CNS) inflammation, elimination of meningeal B cells, and reduction of MOG-specific Th1 and Th17 cells. In contrast, in MOG p35-55-induced EAE, B cells did not become activated or efficiently polarize proinflammatory MOG-specific T cells, similar to naive B cells. In this setting, anti-CD20 treatment exacerbated EAE, and did not impede development of Th1 or Th17 cells. Irrespective of the EAE model used, B-cell depletion reduced the frequency of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Treg), and increased the proinflammatory polarizing capacity of remaining myeloid APCs. INTERPRETATION Our study highlights distinct roles for B cells in CNS autoimmunity. Clinical benefit from anti-CD20 treatment may relate to inhibition of proinflammatory B cell APC function. In certain clinical settings, however, elimination of unactivated B cells, which participate in regulation of T cells and other APC, may be undesirable. Differences in immune responses to MOG protein and peptide may be important considerations when choosing an EAE model for testing novel B cell-targeting agents for MS.
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Affiliation(s)
- Martin S Weber
- Department of Neurology and Program in Immunology, University of California, San Francisco, CA 94143-0114, USA
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419
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Jarius S, Franciotta D, Paul F, Ruprecht K, Bergamaschi R, Rommer PS, Reuss R, Probst C, Kristoferitsch W, Wandinger KP, Wildemann B. Cerebrospinal fluid antibodies to aquaporin-4 in neuromyelitis optica and related disorders: frequency, origin, and diagnostic relevance. J Neuroinflammation 2010; 7:52. [PMID: 20825655 PMCID: PMC2945323 DOI: 10.1186/1742-2094-7-52] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 09/08/2010] [Indexed: 12/04/2022] Open
Abstract
Background In 70-80% of cases, neuromyelitis optica (NMO) is associated with highly specific serum auto-antibodies to aquaporin-4 (termed AQP4-Ab or NMO-IgG). Recent evidence strongly suggests that AQP4-Ab are directly involved in the immunopathogenesis of NMO. Objective To assess the frequency, syndrome specificity, diagnostic relevance, and origin of cerebrospinal fluid (CSF) AQP4-Ab in patients with NMO spectrum disorders (NMOSD). Methods 87 CSF samples from 37 patients with NMOSD and 42 controls with other neurological diseases were tested for AQP4-Ab in a cell based assay using recombinant human AQP4. Twenty-three paired CSF and serum samples from AQP4-Ab seropositive NMOSD patients were further analysed for intrathecal IgG synthesis to AQP4. Results AQP4-Ab were detectable in 68% of CSF samples from AQP4-Ab seropositive patients with NMOSD, but in none of the CSF samples from AQP4-Ab seronegative patients with NMOSD and in none of the control samples. Acute disease relapse within 30 days prior to lumbar puncture, AQP4-Ab serum titres >1:250, and blood-CSF barrier dysfunction, but not treatment status, predicted CSF AQP4-Ab positivity. A positive AQP4-specific antibody index was present in 1/23 samples analysed. Conclusions AQP4-Ab are detectable in the CSF of most patients with NMOSD, mainly during relapse, and are highly specific for this condition. In the cohort analysed in this study, testing for CSF AQP4-Ab did not improve the sensitivity and specificity of the current diagnostic criteria for NMO. The substantial lack of intrathecal AQP4-Ab synthesis in patients with NMOSD may reflect the unique localisation of the target antigen at the blood brain barrier, and is important for our understanding of the immunopathogenesis of the disease.
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Affiliation(s)
- Sven Jarius
- Division of Molecular Neuroimmunology, Department of Neurology, University of Heidelberg, Heidelberg, Germany
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420
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Parratt JDE, Prineas JW. Neuromyelitis optica: a demyelinating disease characterized by acute destruction and regeneration of perivascular astrocytes. Mult Scler 2010; 16:1156-72. [PMID: 20823059 DOI: 10.1177/1352458510382324] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND A serum antibody directed against astrocytes is present in a high proportion of patients with neuromyelitis optica (NMO). The pathogenicity of the antibody is uncertain because no consistent astrocyte lesion is known to occur in NMO. OBJECTIVE To determine whether there is an astrocyte lesion in NMO and if this differs from astrocyte changes in multiple sclerosis (MS). METHODS Astrocyte pathology in early (still-myelinated) lesions and subacute NMO and MS lesions was examined immunohistochemically and in sections stained for astrocytes using routine histological techniques. RESULTS Demyelination in early NMO lesions is accompanied by oligodendrocyte apoptosis in a pattern identical to that seen in MS and this is preceded by an abrupt destruction of perivascular astrocytes. Reparative astrogliosis is effected by a population of unipolar, new astrocytes. Evidence of a different type of astrocyte lesion was found in MS. DISCUSSION The findings add to experimental evidence that the antibody is pathogenic. They also raise the possibility that demyelination in MS may be a bystander effect of an astrocyte lesion, i.e. that MS is not a disease primarily of myelin and oligodendrocytes.
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Affiliation(s)
- John D E Parratt
- The Institute of Clinical Neurosciences, Department of Medicine, The University of Sydney, NSW, Australia
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421
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Meinl E, Derfuss T, Krumbholz M, Pröbstel AK, Hohlfeld R. Humoral autoimmunity in multiple sclerosis. J Neurol Sci 2010; 306:180-2. [PMID: 20817206 DOI: 10.1016/j.jns.2010.08.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 08/05/2010] [Accepted: 08/09/2010] [Indexed: 11/15/2022]
Abstract
The important role of B cells and autoantibodies in the pathogenesis of MS is increasingly appreciated. The recruitment and maintenance of B cells and plasma cells in MS lesions is presumably based on local production of lymphoid chemokines and B cell activation factor of the TNF family (BAFF). The failure of the clinical trial with Atacicept targeting BAFF and its relative APRIL was a great surprise and cannot readily be explained. A role for BAFF in CNS physiology, e.g. via targeting of the Nogo-66 receptor might have to be considered. The identification of patient subgroups based on autoantibodies is a future challenge. Currently patients with neuromyelitis optica (NMO) can be identified by antibodies to aquaporin 4 and about a third of children with acquired demyelinating diseases have antibodies against conformationally correct MOG, while such antibodies are hardly found in adult MS patients. Searching for new targets of the autoimmune response in adult MS patients, we have identified two axo-glial proteins focused around the node of Ranvier, namely neurofascin and contactin-2/TAG-1. Testing the functional relevance of such an autoimmune response in animal models revealed that antibodies to neurofascin may induce axonal injury and that T cells specific for contactin-2/TAG-1 mediate preferentially gray matter injury.
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Affiliation(s)
- Edgar Meinl
- Department of Neuroimmunology, Max Planck Institute of Neurobiology, Am Klopferspitz 18, 82152 Martinsried, Germany.
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422
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Marignier R. Anti-aquaporin-4 antibodies in Devic's neuromyelitis optica: therapeutic implications. Ther Adv Neurol Disord 2010; 3:311-21. [PMID: 21179621 PMCID: PMC3002663 DOI: 10.1177/1756285610382478] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Devic's neuromyelitis optica (DNMO) is a demyelinating and inflammatory disease of the central nervous system (CNS) essentially restricted to the spinal cord and the optic nerves. It is a rare disorder with a prevalence estimated at less than 1/100,000 in Western countries. Since the first description by Eugène Devic in 1894, the relationship between DNMO and multiple sclerosis (MS) has been controversial. Recent clinical, epidemiological, pathological and immunological data demonstrate that MS and DNMO are distinct entities. This distinction between DNMO and MS is crucial, as prognosis and treatment are indeed different. DNMO is now considered to be an autoimmune, antibody-mediated disease especially since the identification of a specific serum autoantibody, named NMO-IgG and directed against the main water channel of the CNS, aquaporin-4 (AQP4). The assessment of AQP4 antibodies (Abs) has initially been proposed to differentiate DNMO and MS. It has also enlarged the clinical spectrum of DNMO and proved to be helpful in predicting relapses and conversion to DNMO after a first episode of longitudinally extensive transverse myelitis or isolated optic neuritis. Lastly, the discovery of the pathogenic role of AQP4 Abs in DNMO leads to a better understanding of detailed DNMO immunopathology and the elaboration of relevant novel treatment strategies specific to DNMO. In this review, we summarize the present and future therapeutic implications generated by the discovery of the various pathogenic mechanisms of AQP4 Abs in DNMO pathophysiology.
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Affiliation(s)
- Romain Marignier
- Service de Neurologie A and EDMUS Coordinating Center, Hôpital Neurologique Pierre Wertheimer, Hospices Civils de Lyon, Lyon, F-69677, France
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423
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Sharma R, Fischer MT, Bauer J, Felts PA, Smith KJ, Misu T, Fujihara K, Bradl M, Lassmann H. Inflammation induced by innate immunity in the central nervous system leads to primary astrocyte dysfunction followed by demyelination. Acta Neuropathol 2010; 120:223-36. [PMID: 20532539 PMCID: PMC2892605 DOI: 10.1007/s00401-010-0704-z] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 05/25/2010] [Accepted: 05/25/2010] [Indexed: 11/26/2022]
Abstract
Primary loss and dysfunction of astrocytes may trigger demyelination, as seen in neuromyelitis optica, an inflammatory disease of the central nervous system. In most patients affected by this disease, injury to astrocytes is initiated by the action of autoantibodies targeting aquaporin 4 (AQP-4), a water channel on astrocytes. We show here that damage of astrocytes and subsequent demyelination can also occur in the absence of autoantibody-mediated mechanisms. Following injection of lipopolysaccharide into the white matter initial microglia activation is followed by a functional disturbance of astrocytes, mainly reflected by retraction of astrocytic foot processes at the glia limitans and loss of AQP-4 and connexins, which are involved in the formation of gap junctions between astrocytes and oligodendrocytes. Demyelination and oligodendrocyte degeneration in this model follows astrocyte pathology. Similar structural abnormalities were also seen in a subset of active lesions in multiple sclerosis. Our studies suggest that astrocyte injury may be an important early step in the cascade of lesion formation in brain inflammation.
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MESH Headings
- Animals
- Aquaporin 4/metabolism
- Astrocytes/immunology
- Astrocytes/pathology
- Cells, Cultured
- Central Nervous System/pathology
- Coculture Techniques/methods
- Disease Models, Animal
- Encephalomyelitis, Autoimmune, Experimental/etiology
- Encephalomyelitis, Autoimmune, Experimental/immunology
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Gene Expression Regulation/drug effects
- Gene Expression Regulation/immunology
- Humans
- Immunity, Innate
- Membrane Proteins/metabolism
- Microscopy, Confocal/methods
- Multiple Sclerosis/immunology
- Multiple Sclerosis/pathology
- Nerve Tissue Proteins/metabolism
- Neuroglia/drug effects
- Polysaccharides/pharmacology
- Rats
- Time Factors
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Affiliation(s)
- Rakhi Sharma
- Centre for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Marie-Therese Fischer
- Centre for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Jan Bauer
- Centre for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Paul A. Felts
- Institute of Neurology, University College London, London, UK
- Centre for Anatomy and Human Identification, University of Dundee, Dundee, Scotland, UK
| | | | - Tatsuro Misu
- Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kazuo Fujihara
- Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Monika Bradl
- Centre for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
| | - Hans Lassmann
- Centre for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria
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424
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Stadelmann C, Wegner C, Brück W. Inflammation, demyelination, and degeneration - recent insights from MS pathology. Biochim Biophys Acta Mol Basis Dis 2010; 1812:275-82. [PMID: 20637864 DOI: 10.1016/j.bbadis.2010.07.007] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 06/30/2010] [Accepted: 07/06/2010] [Indexed: 12/29/2022]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system which responds to anti-inflammatory treatments in the early disease phase. However, the pathogenesis of the progressive disease phase is less well understood, and inflammatory as well as neurodegenerative mechanisms of tissue damage are currently being discussed. This review summarizes current knowledge on the interrelation between inflammation, demyelination, and neurodegeneration derived from the study of human autopsy and biopsy brain tissue and experimental models of MS.
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425
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Sellner J, Boggild M, Clanet M, Hintzen RQ, Illes Z, Montalban X, Du Pasquier RA, Polman CH, Sorensen PS, Hemmer B. EFNS guidelines on diagnosis and management of neuromyelitis optica. Eur J Neurol 2010; 17:1019-32. [PMID: 20528913 DOI: 10.1111/j.1468-1331.2010.03066.x] [Citation(s) in RCA: 293] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND AND PURPOSE Neuromyelitis optica (NMO) or Devic's disease is a rare inflammatory and demyelinating autoimmune disorder of the central nervous system (CNS) characterized by recurrent attacks of optic neuritis (ON) and longitudinally extensive transverse myelitis (LETM), which is distinct from multiple sclerosis (MS). The guidelines are designed to provide guidance for best clinical practice based on the current state of clinical and scientific knowledge. SEARCH STRATEGY Evidence for this guideline was collected by searches for original articles, case reports and meta-analyses in the MEDLINE and Cochrane databases. In addition, clinical practice guidelines of professional neurological and rheumatological organizations were studied. RESULTS Different diagnostic criteria for NMO diagnosis [Wingerchuk et al. Revised NMO criteria, 2006 and Miller et al. National Multiple Sclerosis Society (NMSS) task force criteria, 2008] and features potentially indicative of NMO facilitate the diagnosis. In addition, guidance for the work-up and diagnosis of spatially limited NMO spectrum disorders is provided by the task force. Due to lack of studies fulfilling requirement for the highest levels of evidence, the task force suggests concepts for treatment of acute exacerbations and attack prevention based on expert opinion. CONCLUSIONS Studies on diagnosis and management of NMO fulfilling requirements for the highest levels of evidence (class I-III rating) are limited, and diagnostic and therapeutic concepts based on expert opinion and consensus of the task force members were assembled for this guideline.
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Affiliation(s)
- J Sellner
- Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Germany.
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426
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Kountouras J, Gavalas E, Deretzi G, Boziki M, Zavos C, Chatzopoulos D, Katsinelos P, Giartza-Taxidou E, Grigoriadis N, Venizelos I. Helicobacter pylori with or without its neutrophil-activating protein may be the common denominator associated with multiple sclerosis and neuromyelitis optica. Mult Scler 2010; 16:376-7; author reply 378-9. [PMID: 20203152 DOI: 10.1177/1352458509360550] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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427
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Antibodies to aquaporin-4 in non-small cell lung cancer: a study on 50 patients. Neurol Sci 2010; 31:871-2. [DOI: 10.1007/s10072-010-0290-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Accepted: 04/08/2010] [Indexed: 10/19/2022]
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428
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429
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Illes Z. Pathogenesis, diagnosis and treatment of neuromyelitis optica: Changing concept of an old disease. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1759-1961.2010.00011.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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430
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431
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Abstract
Leukoencephalopathies in adults are frequent and exhibit highly variable aetiology, including multiple acquired causes such as inflammatory, vascular or toxic diseases and neoplasias. In contrast leukodystrophies are genetically determined, chronic progressive myelin disorders with a variable pathogenetic background and a great diversity of clinical and paraclinical findings. Some diseases, namely those with an additional inborn error of metabolism, are treatable. Genetic counselling appears to be of major importance for patients and their families. In the light of numerous acquired adulthood leukoencephalopathies a clear delineation of late-onset genetic leukodystrophies is necessary. Clinical symptoms and MRI patterns of some of the major leukodystrophies are reported, including possibilities of biochemical and genetic testing.
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Affiliation(s)
- T Weber
- Klinik für Neurologie, Marienkrankenhaus Hamburg, 22087 Hamburg.
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432
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Sargsyan SA, Shearer AJ, Ritchie AM, Burgoon MP, Anderson S, Hemmer B, Stadelmann C, Gattenlöhner S, Owens GP, Gilden D, Bennett JL. Absence of Epstein-Barr virus in the brain and CSF of patients with multiple sclerosis. Neurology 2010; 74:1127-35. [PMID: 20220124 DOI: 10.1212/wnl.0b013e3181d865a1] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
OBJECTIVE Epstein-Barr virus (EBV) is a ubiquitous human herpesvirus that becomes latent in B-lymphocytes and has been implicated in the pathogenesis of multiple sclerosis (MS). We searched for latent and active EBV infection in MS brain and CSF. METHODS Nested and non-nested real-time PCR were used to detect cell-specific and EBV-specific transcripts in 15 fresh-frozen and 5 formalin-fixed paraffin-embedded MS plaques and in single MS CSF B-lymphocytes and plasma cells. Intrathecal anti-EBV antibody synthesis was measured by ELISA. Immunocytochemistry was used to detect binding of MS CSF and recombinant antibodies (rAbs) generated from clonally expanded plasma cells in MS CSF to EBV-infected cells. RESULTS No EBV RNA was found in MS CSF B-lymphocytes or plasma cells. In active MS plaques, EBV-encoded RNA (EBER)-1 was the only and rarely detected transcript. The frequency of detected intrathecal anti-EBV antibody synthesis in patients with MS did not differ from that in non-MS inflammatory CNS disease control patients. Anti-EBV antibodies were detected in the CSF of patients with MS, but MS rAbs did not react with EBV. CONCLUSIONS Application of real-time PCR to multiple sclerosis brain and single B-lymphocytes in CSF did not reveal any evidence of active Epstein-Barr virus infection.
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Affiliation(s)
- S A Sargsyan
- Department of Neurology,University of Colorado Denver School of Medicine, Aurora, CO 80045, USA
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433
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Meinl E, Derfuss T, Linington C. Identifying targets for autoantibodies in CNS inflammation: Strategies and achievements. ACTA ACUST UNITED AC 2010. [DOI: 10.1111/j.1759-1961.2009.00006.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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434
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Kinoshita M, Nakatsuji Y, Kimura T, Moriya M, Takata K, Okuno T, Kumanogoh A, Kajiyama K, Yoshikawa H, Sakoda S. Anti-aquaporin-4 antibody induces astrocytic cytotoxicity in the absence of CNS antigen-specific T cells. Biochem Biophys Res Commun 2010; 394:205-10. [PMID: 20188706 DOI: 10.1016/j.bbrc.2010.02.157] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2010] [Accepted: 02/23/2010] [Indexed: 11/28/2022]
Abstract
Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system (CNS). Anti-aquaporin-4 antibody (AQP4-Ab) is a highly specific serum autoantibody that is detected in patients with NMO. Several lines of evidence indicate that AQP4-Ab not only serves as a disease marker but also plays a pivotal role in the pathogenesis of NMO. Although the pathogenicity of AQP4-Ab in vivo has recently been demonstrated, the presence of CNS antigen-specific T cells is recognized as a prerequisite for the antibody to exert pathogenic effects. Thus, it remains unclear whether AQP4-Ab is the primary cause of the disease or a disease-modifying factor in NMO. Here we report that pre-treatment with complete Freund's adjuvant (CFA) alone is sufficient for AQP4-Ab to induce astrocytic damage in vivo. Our results show the primary pathogenic role of AQP4-Ab in the absence of CNS antigen-specific T cells, and suggest that danger signals provided by nonspecific inflammation can be a trigger for those who harbor the autoantibody to develop NMO.
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Affiliation(s)
- Makoto Kinoshita
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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435
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Brilot F, Dale RC, Selter RC, Grummel V, Kalluri SR, Aslam M, Busch V, Zhou D, Cepok S, Hemmer B. Antibodies to native myelin oligodendrocyte glycoprotein in children with inflammatory demyelinating central nervous system disease. Ann Neurol 2010; 66:833-42. [PMID: 20033986 DOI: 10.1002/ana.21916] [Citation(s) in RCA: 214] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Myelin oligodendrocyte glycoprotein (MOG) is a candidate target antigen in demyelinating diseases of the central nervous system (CNS). Although MOG is encephalitogenic in different animal models, the relevance of this antigen in human autoimmune diseases of the CNS is still controversial. METHODS We investigated the occurrence and biological activity of antibodies to native MOG (nMOG) in 47 children during a first episode of CNS demyelination (acute disseminated encephalomyelitis [ADEM], n = 19 and clinical isolated syndrome [CIS], n = 28) by a cell-based bioassay. RESULTS High serum immunoglobulin G (IgG) titers to nMOG were detected in 40% of children with CIS/ADEM but 0% of the control children affected by other neurological diseases, healthy children, or adults with inflammatory demyelinating diseases, respectively. By contrast, IgM antibodies to nMOG occurred in only 3 children affected by ADEM. Children with high anti-nMOG IgG titer were significantly younger than those with low IgG titer. Anti-nMOG IgG titers did not differ between the ADEM and CIS group, and did not predict conversion from CIS to MS during a mean 2-year follow-up. However, intrathecal IgG anti-MOG antibody synthesis was only seen in CIS children. IgG antibodies to nMOG not only bound to the extracellular domain of nMOG, but also induced natural killer cell-mediated killing of nMOG-expressing cells in vitro. INTERPRETATION Overall, these findings suggest nMOG as a major target of the humoral immune response in a subgroup of children affected by inflammatory demyelinating diseases of the CNS. Children may provide valuable insight into the earliest immune mechanisms of CNS demyelination.
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Affiliation(s)
- Fabienne Brilot
- Neuroimmunology Group, Institute for Neuroscience and Muscle Research, the Kids Research Institute at the Children's Hospital at Westmead, University of Sydney, Sydney, Australia
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436
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Tajima M, Crane JM, Verkman AS. Aquaporin-4 (AQP4) associations and array dynamics probed by photobleaching and single-molecule analysis of green fluorescent protein-AQP4 chimeras. J Biol Chem 2010; 285:8163-70. [PMID: 20071343 DOI: 10.1074/jbc.m109.093948] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The plasma membrane assembly of aquaporin-4 (AQP4) water channels into orthogonal arrays of particles (OAPs) involves interactions of AQP4 N-terminal domains. To study in live cells the site of OAP assembly, the size and dynamics of plasma membrane OAPs, and the heterotetrameric associations of AQP4, we constructed green fluorescent protein (GFP)-labeled AQP4 "long" (M1) and "short" (M23) isoforms in which GFP was inserted at the cytoplasm-facing N or C terminus or between Val-141 and Val-142 in the second extracellular loop of AQP4. The C-terminal and extracellular loop GFP insertions did not interfere with the rapid unrestricted membrane diffusion of GFP-labeled M1 or the restricted diffusion and OAP assembly of GFP-labeled M23. Photobleaching of brefeldin A-treated cells showed comparable and minimally restricted diffusion of M1 and M23, indicating that OAP assembly occurs post-endoplasmic reticulum. Single-molecule step photobleaching and intensity analysis of GFP-labeled M1 in the absence versus presence of excess unlabeled M1 or M23 with an OAP-disrupting mutation indicated heterotetrameric AQP4 association. Time-lapse total internal reflection fluorescence imaging of M23 in live cells at 37 degrees C indicated that OAPs diffuse slowly (D approximately 10(-12) cm(2)/s) and rearrange over tens of minutes. Our biophysical measurements in live cells thus reveal extensive AQP4 monomer-monomer and tetramer-tetramer interactions.
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Affiliation(s)
- Masato Tajima
- Departments of Medicine and Physiology, University of California, San Francisco, California 94143, USA
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437
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Crane JM, Bennett JL, Verkman AS. Live cell analysis of aquaporin-4 m1/m23 interactions and regulated orthogonal array assembly in glial cells. J Biol Chem 2010; 284:35850-60. [PMID: 19843522 DOI: 10.1074/jbc.m109.071670] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Aquaporin-4 (AQP4) can assemble into supramolecular aggregates called orthogonal arrays of particles (OAPs). In cells expressing single AQP4 isoforms, we found previously that OAP formation by AQP4-M23 requires N terminus interactions just downstream of Met-23 and that the inability of AQP4-M1 to form OAPs involves blocking by residues upstream of Met-23. Here, we studied M1/M23 interactions and regulated OAP assembly by nanometer-resolution tracking of quantum dot-labeled AQP4 in live cells expressing differentially tagged AQP4 isoforms and in primary glial cell cultures in which native AQP4 was labeled with a monoclonal recombinant neuromyelitis optica autoantibody. OAP assembly was assessed independently by Blue Native gel electrophoresis. We found that OAPs in native glial cells could be reproduced in transfected cells expressing equal amounts of AQP4-M1 and -M23. Mutants of M23 that do not themselves form OAPs, including M23-F26Q and M23-G28P, were able to fully co-associate with native M23 to form large immobile OAPs. Analysis of a palmitoylation-null M1 mutant (C13A/C17A) indicated palmitoylation-dependent OAP assembly only in the presence of M23, with increased M1 palmitoylation causing progressive OAP disruption. Differential regulation of OAP assembly by palmitoylation, calcium elevation, and protein kinase C activation was found in primary glial cell cultures. We conclude that M1 and M23 co-assemble in AQP4 OAPs and that specific signaling events can regulate OAP assembly in glial cells.
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Affiliation(s)
- Jonathan M Crane
- Departments of Medicine and Physiology, University of California, San Francisco, California 94143, USA
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438
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Saadoun S, Waters P, Bell BA, Vincent A, Verkman AS, Papadopoulos MC. Intra-cerebral injection of neuromyelitis optica immunoglobulin G and human complement produces neuromyelitis optica lesions in mice. ACTA ACUST UNITED AC 2010; 133:349-61. [PMID: 20047900 DOI: 10.1093/brain/awp309] [Citation(s) in RCA: 408] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system associated with autoantibodies against the glial water channel protein aquaporin-4. It has recently been reported that immunoglobulin from neuromyelitis optica patients injected peripherally does not cause lesions in naive rats, but only when pre-existing central nervous system inflammation is present. Here, we investigated whether immunoglobulin G from aquaporin-4-autoantibody-positive neuromyelitis optica patients has the potential to damage the central nervous system either alone or in the presence of human complement. Immunoglobulin G from neuromyelitis optica patients did not activate mouse complement and was not pathogenic when injected into mouse brain. However, co-injection of immunoglobulin G from neuromyelitis optica patients with human complement produced neuromyelitis optica-like lesions in mice. Within 12 h of co-injecting immunoglobulin G from neuromyelitis optica patients and human complement, there was a striking loss of aquaporin-4 expression, glial cell oedema, myelin breakdown and axonal injury, but little intra-parenchymal inflammation. At 7 days, there was extensive inflammatory cell infiltration, perivascular deposition of activated complement components, extensive demyelination, loss of aquaporin-4 expression, loss of reactive astrocytes and neuronal cell death. In behavioural studies, mice injected with immunoglobulin G from neuromyelitis optica patients and human complement into the right hemisphere preferentially turned to the right at 7 days. No brain inflammation, demyelination or right-turning behaviour was seen in wild-type mice that received immunoglobulin G from non-neuromyelitis optica patients with human complement, or in aquaporin-4-null mice that received immunoglobulin G from neuromyelitis optica patients with human complement. We conclude that co-injection of immunoglobulin G from neuromyelitis optica patients with human complement reproduces the key histological features of neuromyelitis optica and that aquaporin-4 is necessary and sufficient for immunoglobulin G from neuromyelitis optica patients to exert its effect. In our mouse model, immunoglobulin G from neuromyelitis optica patients does not require pre-existing central nervous system inflammation to produce lesions.
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439
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Bradl M, Misu T, Takahashi T, Watanabe M, Mader S, Reindl M, Adzemovic M, Bauer J, Berger T, Fujihara K, Itoyama Y, Lassmann H. Neuromyelitis optica: pathogenicity of patient immunoglobulin in vivo. Ann Neurol 2009; 66:630-43. [PMID: 19937948 DOI: 10.1002/ana.21837] [Citation(s) in RCA: 422] [Impact Index Per Article: 28.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Severe inflammation and astrocyte loss with profound demyelination in spinal cord and optic nerves are typical pathological features of neuromyelitis optica (NMO). A diagnostic hallmark of this disease is the presence of serum autoantibodies against the water channel aquaporin-4 (AQP-4) on astrocytes. METHODS We induced acute T-cell-mediated experimental autoimmune encephalomyelitis in Lewis rats and confronted the animals with an additional application of immunoglobulins from AQP-4 antibody-positive and -negative NMO patients, multiple sclerosis patients, and control subjects. RESULTS The immunoglobulins from AQP-4 antibody-positive NMO patients are pathogenic. When they reach serum titers in experimental animals comparable with those seen in NMO patients, they augment clinical disease and induce lesions in the central nervous system that are similar in structure and distribution to those seen in NMO patients, consisting of AQP-4 and astrocyte loss, granulocytic infiltrates, T cells and activated macrophages/microglia cells, and an extensive immunoglobulin and complement deposition on astrocyte processes of the perivascular and superficial glia limitans. AQP-4 antibody containing NMO immunoglobulin injected into naïve rats, young rats with leaky blood-brain barrier, or after transfer of a nonencephalitogenic T-cell line did not induce disease or neuropathological alterations in the central nervous system. Absorption of NMO immunoglobulins with AQP-4-transfected cells, but not with mock-transfected control cells, reduced the AQP-4 antibody titers and was associated with a reduction of astrocyte pathology after transfer. INTERPRETATION Human anti-AQP-4 antibodies are not only important in the diagnosis of NMO but also augment disease and induce NMO-like lesions in animals with T-cell-mediated brain inflammation.
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Affiliation(s)
- Monika Bradl
- Department of Neuroimmunology, Medical University Vienna, Center for Brain Research, Vienna, Austria
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440
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Abstract
This article is based on the ECTRIMS lecture given at the 25( th) ECTRIMS meeting which was held in Dusseldorf, Germany, from 9 to 12 September 2009. Five challenges have been identified: (1) safeguarding the principles of medical ethics; (2) optimizing the risk/benefit ratio; (3) bridging the gap between multiple sclerosis and experimental autoimmune encephalitis; (4) promoting neuroprotection and repair; and (5) tailoring multiple sclerosis therapy to the individual patient. Each of these challenges will be discussed and placed in the context of current research into the pathogenesis and treatment of multiple sclerosis.
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Affiliation(s)
- Reinhard Hohlfeld
- Institute of Clinical Neuroimmunology, Ludwig Maximilians University of Munich, München, Germany.
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