Medical University of Vienna
Center for Brain Research

Author Of 1 Presentation

Observational Studies Oral Presentation

PS02.04 - Relation between perivascular mononuclear infiltrates and plaque formation in the cortex and basal ganglia in progressive multiple sclerosis (MS).

Speakers
Presentation Number
PS02.04
Presentation Topic
Observational Studies
Lecture Time
10:57 - 11:09

Abstract

Background

Cortical plaque loads in primary progressive (PP) and secondary progressive MS (SP) appear equal whereas meningeal perivascular mononuclear/lymphocytic infiltration (PMI) may be more pronounced in SP. Basal ganglia may also be a predilection site in progressive MS.

Objectives

To compare cortical and basal ganglia plaque formation and PMI in large tissue areas from clinically well-defined PP and SP patients.

Methods

Large brain sections from clinically well-described patients with PP (N=12), SP (N=14) and 11 age-matched controls were stained with HE, Luxol-fast blue and in patients additionally for proteolipid protein and CD68. T- and B-cells were confirmed in PMI’s by CD3 and CD 20 in 3 PP and 3 SP patients. We measured total plaque, microglia-rimmed slowly expanding plaque and macrophage-filled filled active plaque area loads (% of cortex or basal ganglia area), PMI densities (#/Cm2 or #/Cm meningeal length) and mean PMI size. PMI’s with min. size score one had 3-4 perivascular cell rows and 20-50 cells whereas max. score six had >19 rows and >500 cells. In one PP patient, cortical slowly expanding rims were confirmed by immunofluorescence showing IgG. Expanded Disability Status Scale (EDSS) score was estimated by chart review in a blinded fashion among 20 patients (10 PP and 12SP) from whom charts were available from two time points including one within three yrs. before death. Among these, we calculated ΔEDSS/yr. before death.

Results

Tissue areas and meningeal lengths were similar in PP and SP. Both groups displayed similarly elevated cortical plaque loads and PMI densities in the cortex and meninges. However, meningeal PMI size as well as basal ganglia (6 SP vs 8 PP) plaque load and PMI density tended to be higher in SP vs PP. Meningeal PMI density correlated with total cortical plaque load while meningeal PMI size correlated with cortical slowly expanding plaque. Cortical PMI density and size correlated with active and slowly expanding (but not total) cortical plaque. PMI’s and plaque also correlated in the basal ganglia, albeit only in SP. Overall, age at death correlated negatively with PMI’s in the meninges, cortex and in the basal ganglia. Δ EDSS/yr. before death correlated with plaque load and tended to correlate with PMI’s, albeit only in the basal ganglia.

Conclusions

Perivascular immune activation in the meninges, cortex and basal ganglia may be pathogenic, driving grey matter demyelination in progressive MS.

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Author Of 3 Presentations

Pathogenesis – the Blood-Brain Barrier Poster Presentation

P0955 - Diffuse inflammation relates to demyelination and clinical parameters in primary (PP) and secondary progressive multiple sclerosis (SP). (ID 1181)

Speakers
Presentation Number
P0955
Presentation Topic
Pathogenesis – the Blood-Brain Barrier

Abstract

Background

In primary progressive MS (PP), brain plaques are smaller and remyelinate better than in secondary progressive MS (SP) yet prognosis and response to systemic immunotherapy in PP is poor.

Objectives

To investigate relations between inflammation and myelin injury in PP vs SP and find correlates of clinical progression.

Methods

Large brain sections from clinically well-described post-mortem cohorts (12 PP, 14 SP and 11 controls) were stained with HE and Luxol-fast blue (myelin). Patients were additionally stained for proteolipid protein and CD68. We measured area loads of total plaque, microglia-rimmed slowly expanding plaque and macrophage-filled filled active plaque (% of WM area). Myelin density in the white matter overall, the normally appearing (NAWM), and the diffusely injured white matter (DIWM) was assessed by densitometry in ImageJ. In white matter compartments, we measured the density and mean size of perivascular mononuclear infiltrates (PMI; #/Cm2). The minimal PMI (grade one) had 3-4 perivascular cell rows and 20-50 cells whereas max. grade six had >19 rows and >500 cells. T- and B-cells in PMI’s were confirmed by CD3 and CD20. EDSS was estimated by chart review in a blinded fashion among 20 patients (10 PP and 12SP) from whom charts were available from two time points including one within three yrs. before death. Among these, we calculated Δ EDSS/yr before death.

In parallel, in-vivo cohorts (26 PP, 26 SP and 24 controls) were analyzed for MRI lesions with/without Gadolinium-enhancement and cerebrospinal fluid (CSF)-biomarkers of demyelination (MBP), axonal damage (NFL) and inflammation.

Results

Densities and sizes of PMI’s in NAWM as well as CSF-markers of inflammation (e.g. IgG-indices, CXCL13, MMP9) were equally increased in PP and SP and equally large PMI’s located to periventricular zones (median gr 1,8 IQR 1,5-2,1). Active and total lesion formation were higher in SP than in PP in both post-mortem and in-vivo cohorts and (post-mortem) juxtacortical and meningeal PMI’s were larger in SP than PP. By contrast, more DIWM-pathology was found in PPMS than in SPMS. The overall myelin density (post-mortem) and NAWM magnetic-transfer-ratio (in-vivo) were equally reduced while MBP and NFL levels in the CSF (in-vivo) were equally increased in both groups.

Plaque-distant (NAWM/DIWM) PMI-density (post-mortem cohort) and CSF-inflammation (in-vivo cohort) correlated with active lesion formation in SP, but not in PP. PMI-density and size in NAWM and in the white matter overall correlated with shorter survival. PMI-density in the white matter overall also correlated with slowly exp. plaque load, which in turn, correlated with Δ EDSS/yr before death in PP and in SP.

Conclusions

Perivascular inflammation is pathogenic and may contribute to white matter demyelination in PP and SP. Inflammatory demyelination in the white matter may not differ greatly but may be more diffuse and less focal in PP compared to SP.

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Pathogenesis – Immunology Poster Presentation

P0993 - Reconstitution of a pathogenic antibody of a unique case of human autoimmune encephalitis (ID 248)

Speakers
Presentation Number
P0993
Presentation Topic
Pathogenesis – Immunology

Abstract

Background

Multiple sclerosis is a chronic inflammatory demyelinating disease potentially driven by autoimmunity. Active immunization of humans with brain tissue, as shown following rabies vaccination or misguided “cell therapeutic” approaches, can trigger autoimmune encephalomyelitis, which in rare cases may reflect the pathology of multiple sclerosis (Höftberger et al 2015). The specific brain autoantigen(s) recognized by the immune system in such a condition are presently unknown.

Objectives

Aim of our study was to reconstruct dominant auto-antibodies from formalin fixed paraffin embedded brain material of such a case and to test immunoreactivity and pathogenicity of the respective reconstructed recombinant antibodies.

Methods

RNA was isolated of three different lesions sites of this case with large B lineage cell infiltrates for generating libraries for antibody repertoire analysis. Clonally expanded heavy and light immunoglobulin chains were cloned and antibodies were produced and purified using the ExPi293 expression system. Flow cytometry was used to test antibody binding to either full length human, rat or mouse myelin oligodendrocyte glycoprotein (MOG) and different MOG mutants were used to determine the specific antibody binding site. Immunohistochemistry was performed on human brain tissue to confirm the Flow Cytometry data. Finally, we tested the demyelinating activity of the reconstructed recombinant antibody after transfer into rats with T-cell mediated brain inflammation.

Results

We identified clonal expansion of one heavy and one light immunoglobulin chain, which together form a functional antibody (the “hAE antibody”). This antibody recognized human, rat and mouse full length MOG and shared some but not all binding sites to MOG with the 8-18C5 recombinant anti-MOG antibody. The antibody bound to myelin in tissue sections of humans, mice and rats and induced specific primary demyelination with complement activation after passive transfer in rats in vivo.

Conclusions

Our study shows that it is possible to resurrect a disease promoting antibody from formaldehyde fixed and paraffin embedded autopsy tissue of a patient, who died more than 60 years ago. It further shows that like in rodents and primates auto-immunization of humans with brain tissue induces a pathogenic auto-antibody response, which can amplify demyelination in the context of brain inflammation.

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Invited Presentations Invited Abstracts

TC09.02 - What is the pathological substrate of progressive MS (ID 615)

Speakers
Authors
Presentation Number
TC09.02
Presentation Topic
Invited Presentations

Abstract

Abstract

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Active demyelination and ongoing neurodegeneration are invariably associated with inflammation, irrespective of the clinical course of the disease. The inflammatory reaction in the CNS in all disease stages is dominated by CD8+ T-lymphocytes, B-cells and plasma cells. In active phases of the disease high numbers of CD20+ B-cells are seen, while plasma blasts and plasma cells increase with chronicity of the disease. The CD8+ T-cells display a phenotype of tissue resident memory cells, which show focally and temporally restricted activation. While new contrast enhancing lesions dominate the pathology of early stages of MS, the chronic active and / or slowly expanding lesions are a characteristic feature of the pathology in the white matter in patients with progressive disease. Serial MRI scans at 7T show that such lesions gradually expand over a time period of more than 5 years. Another characteristic feature of progressive MS is the accumulation of widespread subpial demyelinated lesions in the cerebral and cerebellar cortex and on the surface of the brain stem and spinal cord. Such lesions are similar to slowly expanding lesions in the white matter and, when active, are associated with meningeal inflammation. Thus, pathology suggests that the substrate of disease progression in MS is the slow expansion of pre-existing lesions in the grey and white matter, which is likely to be driven by a compartmentalized inflammatory reaction, mainly located in the meninges and the large perivascular Virchow Robin spaces. This progressive injury gives rise to secondary Wallerian degeneration throughout the brain and spinal cord, followed by atrophy and, when it has passed the threshold of functional compensation, is reflected by slow and uninterrupted clinical disease progression.

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Presenter Of 1 Presentation

Invited Presentations Invited Abstracts

TC09.02 - What is the pathological substrate of progressive MS (ID 615)

Speakers
Authors
Presentation Number
TC09.02
Presentation Topic
Invited Presentations

Abstract

Abstract

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Active demyelination and ongoing neurodegeneration are invariably associated with inflammation, irrespective of the clinical course of the disease. The inflammatory reaction in the CNS in all disease stages is dominated by CD8+ T-lymphocytes, B-cells and plasma cells. In active phases of the disease high numbers of CD20+ B-cells are seen, while plasma blasts and plasma cells increase with chronicity of the disease. The CD8+ T-cells display a phenotype of tissue resident memory cells, which show focally and temporally restricted activation. While new contrast enhancing lesions dominate the pathology of early stages of MS, the chronic active and / or slowly expanding lesions are a characteristic feature of the pathology in the white matter in patients with progressive disease. Serial MRI scans at 7T show that such lesions gradually expand over a time period of more than 5 years. Another characteristic feature of progressive MS is the accumulation of widespread subpial demyelinated lesions in the cerebral and cerebellar cortex and on the surface of the brain stem and spinal cord. Such lesions are similar to slowly expanding lesions in the white matter and, when active, are associated with meningeal inflammation. Thus, pathology suggests that the substrate of disease progression in MS is the slow expansion of pre-existing lesions in the grey and white matter, which is likely to be driven by a compartmentalized inflammatory reaction, mainly located in the meninges and the large perivascular Virchow Robin spaces. This progressive injury gives rise to secondary Wallerian degeneration throughout the brain and spinal cord, followed by atrophy and, when it has passed the threshold of functional compensation, is reflected by slow and uninterrupted clinical disease progression.

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Moderator Of 2 Sessions

Burning Debate Fri, Sep 11, 2020
Session Type
Burning Debate
Date
Fri, Sep 11, 2020
Teaching Course Fri, Sep 11, 2020
Session Type
Teaching Course
Date
Fri, Sep 11, 2020

Invited Speaker Of 1 Presentation

Invited Presentations Invited Abstracts

TC09.02 - What is the pathological substrate of progressive MS (ID 615)

Speakers
Authors
Presentation Number
TC09.02
Presentation Topic
Invited Presentations

Abstract

Abstract

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). Active demyelination and ongoing neurodegeneration are invariably associated with inflammation, irrespective of the clinical course of the disease. The inflammatory reaction in the CNS in all disease stages is dominated by CD8+ T-lymphocytes, B-cells and plasma cells. In active phases of the disease high numbers of CD20+ B-cells are seen, while plasma blasts and plasma cells increase with chronicity of the disease. The CD8+ T-cells display a phenotype of tissue resident memory cells, which show focally and temporally restricted activation. While new contrast enhancing lesions dominate the pathology of early stages of MS, the chronic active and / or slowly expanding lesions are a characteristic feature of the pathology in the white matter in patients with progressive disease. Serial MRI scans at 7T show that such lesions gradually expand over a time period of more than 5 years. Another characteristic feature of progressive MS is the accumulation of widespread subpial demyelinated lesions in the cerebral and cerebellar cortex and on the surface of the brain stem and spinal cord. Such lesions are similar to slowly expanding lesions in the white matter and, when active, are associated with meningeal inflammation. Thus, pathology suggests that the substrate of disease progression in MS is the slow expansion of pre-existing lesions in the grey and white matter, which is likely to be driven by a compartmentalized inflammatory reaction, mainly located in the meninges and the large perivascular Virchow Robin spaces. This progressive injury gives rise to secondary Wallerian degeneration throughout the brain and spinal cord, followed by atrophy and, when it has passed the threshold of functional compensation, is reflected by slow and uninterrupted clinical disease progression.

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