Abstract
This study examined the roles of microglia and monocytes in myelin destruction in patients with early multiple sclerosis (MS). Twenty-two cases were studied; the clinical duration was <9 ...weeks in 10 cases. Twenty myeloid cell subtypes or categories were identified including 2 cell types not known previously to occur in demyelinating diseases. Commencing myelin breakdown in plaques and in perivascular and subpial tissues occurred in the immediate presence of infiltrating monocytes and was effected by a homogeneous population of IgG-positive Fc receptor-bearing early phagocytes interacting with abnormal myelin. Oligodendrocyte apoptosis was observed in intact myelinated tissue bordering areas of active demyelination. Capillaries in the cerebral cortex plugged by large numbers of monocytes were common in acute cases of MS and in a patient with a neuromyelitis optica variant and extreme systemic recruitment of monocytes. In an MS patient with progressive disease, microglial nodules centered on MHC-II-positive capillaries plugged by monocytes were present in the cerebral cortex. This constitutes a new gray matter lesion in MS.
There is little agreement among neuropathologists regarding the timing and nature of oligodendrocyte loss in multiple sclerosis (MS). This review describes changes that accompany acute ...oligodendrocyte loss in new lesions. Included is a description of the immunopathology of new lesions in 23 severe early cases selected from a bank of 300 MS autopsies. Oligodendrocytes in prephagocytic lesions exhibit cytopathic changes that include apoptosis of oligodendrocytes immunoreactive for caspase 3, phagocytosis of apoptotic oligodendrocytes, swelling of cells with abnormal nuclei, complement deposition, and lysis. These are nonspecific changes that provide no clue as to the cause of oligodendrocyte injury. Associated changes include the presence of enlarged immunoglobulin (IgG)+ microglia and early macrophages, the presence nearby of a focus of inflammatory demyelination, an open blood–brain barrier, and the presence of rare CD8 T cells. Myelin contacted by IgG+ macrophages is immunoreactive for complement but not for IgG. It is likely that macrophage activity in evolving white and gray matter plaques is scavenging activity directed at nonvital myelin secondary to oligodendrocytes loss. One feature of MS that is not understood is the extraordinarily close resemblance the disease shows pathologically to neuromyelitis optica (NMO), including that demyelination in both is secondary to a loss of caspase 3‐positive apoptotic oligodendrocytes. These similarities raise the possibility that like NMO, MS is an autoimmune disease in which oligodendrocyte apoptosis is determined by injury to some other glial or mesenchymal component. Ann Neurol 2012;72:18–31
Objective
CD4 T‐cell–dependent macrophage activation directed against a myelin or oligodendrocyte antigen is generally thought to be the mechanism causing myelin destruction in multiple sclerosis ...(MS). However, areas within expanding MS lesions may exhibit prominent oligodendrocyte loss and apoptosis in the absence of infiltrating lymphocytes. The present study was designed to further investigate the inflammatory profile of different regions within rapidly expanding MS lesions.
Methods
Twenty‐six active lesions from 11 patients with early MS were serially sectioned and immunostained for T and B cells, plasma cells, ramified microglia, macrophages, monocytes, and CD209‐positive dendritic cells. Cell counts were compared in prephagocytic, phagocytic, and immediately postphagocytic areas.
Results
Parenchymal T and B cells were largely absent in areas of initial oligodendrocyte loss and in areas of degenerate and dead myelin infiltrated by myelin phagocytes. In contrast, trailing areas of complete demyelination packed with lipid macrophages, and, in some lesions, regenerating oligodendrocytes, showed large numbers of T cells, B cells, and immunoglobulin G (IgG)‐positive plasma cells. Lesions in 2 exceptionally early cases contained relatively few T and B cells, and no IgG‐positive plasma cells.
Interpretation
Early loss of oligodendrocytes is a prominent feature in tissue bordering rapidly expanding MS lesions. Macrophage activity is largely an innate scavenging response to the presence of degenerate and dead myelin. Adaptive immune activity involving T and B cells is conspicuous chiefly in recently demyelinated tissue, which may show signs of oligodendrocyte regeneration. The findings suggest that plaque formation has some basis other than destructive cell‐mediated immunity directed against a myelin or oligodendrocyte antigen. Ann Neurol 2009;66:739–753
Background:
Recognizing the cause of optic neuritis (ON) affects treatment decisions and visual outcomes.
Objective:
We aimed to define radiological features of first-episode demyelinating ON.
...Methods:
We performed blinded radiological assessment of 50 patients presenting with first-episode myelin oligodendrocyte glycoprotein (MOG) antibody-associated ON (MOG-ON; n=19), aquaporin-4 (AQP4) antibody-associated ON (AQP4-ON; n=11), multiple sclerosis (MS)-associated ON (MS-ON; n=13), and unclassified ON (n=7).
Results:
Bilateral involvement was more common in MOG-ON and AQP4-ON than MS-ON (84% vs. 82% vs. 23%), optic nerve head swelling was more common in MOG-ON (53% vs. 9% vs. 0%), chiasmal involvement was more common in AQP4-ON (5% vs. 64% vs. 15%), and bilateral optic tract involvement was more common in AQP4-ON (0% vs. 45% vs. 0%). Retrobulbar involvement was more common in MOG-ON, whereas intracranial involvement was more common in AQP4-ON. MOG-ON and AQP4-ON had longer lesion lengths than MS-ON. The combination of two predictors, the absence of magnetic resonance imaging brain abnormalities and a higher lesion extent score, showed a good ability to discriminate between an autoantibody-associated ON (MOG or AQP4) and MS. AQP4-ON more frequently had severe and sustained visual impairment.
Conclusion:
MOG-ON and AQP4-ON are more commonly bilateral and longitudinally extensive. MOG-ON tends to involve the anterior optic pathway, whereas AQP4-ON the posterior optic pathway.
We have compared five different assays for antibodies to aquaporin-4 in 181 cases of suspected Neuromyelitis optica spectrum disorders (NMOSD) and 253 controls to assess their relative utility. As ...part of a clinically-based survey of NMOSD in Australia and New Zealand, cases of suspected NMOSD were referred from 23 centers. Clinical details and magnetic imaging were reviewed and used to apply the 2015 IPND diagnostic criteria. In addition, 101 age- and sex-matched patients with multiple sclerosis were referred. Other inflammatory disease (
n
= 49) and healthy controls (
n
= 103) were also recruited. Samples from all participants were tested using tissue-based indirect immunofluorescence assays and a subset were tested using four additional ELISA and cell-based assays. Antibodies to myelin oligodendrocyte glycoprotein (MOG) were also assayed. All aquaporin-4 antibody assays proved to be highly specific. Sensitivities ranged from 60 to 94%, with cell-based assays having the highest sensitivity. Antibodies to MOG were detected in 8/79 (10%) of the residual suspected cases of NMOSD. Under the 2015 IPND diagnostic criteria for NMOSD, cell-based assays for aquaporin-4 are sensitive and highly specific, performing better than tissue-based and ELISA assays. A fixed cell-based assay showed near-identical results to a live-cell based assay. Antibodies to MOG account for only a small number of suspected cases.
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.
Objective
To identify evidence of a discrete, specific immune response in multiple sclerosis (MS) by analyzing the distribution of immunoglobulins and complement in tissue derived from cases of MS, ...and from control inflammatory white matter diseases known to express viral and autoantigens in the brain and spinal cord.
Methods
Autopsy tissue from 25 MS patients and 24 patients with other neurological diseases was examined immunohistochemically for immunoglobulins and activated complement (C3d and C9neo).
Results
In tissue remote from focal lesions in MS and other neurological diseases, IgG was detected in many normal structures but not in myelin or ramified microglia. Disrupted myelin in areas of active myelin breakdown and in phagocytes stained positively for C3d and C9neo, and equivocally for IgG in MS and all other neurological diseases examined, including ischemic infarcts. Disease‐specific deposits of IgG or complement were detected in virus‐infected cells in progressive multifocal leukoencephalopathy, subacute sclerosing panencephalitis, and cytomegalovirus encephalitis; in glial‐limiting membranes in neuromyelitis optica; and in senile plaques in Alzheimer's dementia. Specific to MS were unusual microglial nodules containing short, linear deposits of activated complement (C3d) on partly demyelinated axons located in normal‐appearing periplaque white matter.
Interpretation
IgG and complement immunostaining of disrupted myelin in MS lesions, frequently cited as an indication of pathogenic anti‐myelin antibodies, is a nonspecific feature that cannot be interpreted as evidence of a distinct pathogenesis or serve to define particular variants of the disease. The unusual microglial nodules described in this study may constitute a specific biomarker with pathogenetic significance in MS. Ann Neurol 2009;65:32–46
Fibrosis of the Choroid Plexus Filtration Membrane Prineas, John W; Parratt, John D. E; Kirwan, Paul D
Journal of neuropathology and experimental neurology,
2016-September, Letnik:
75, Številka:
9
Journal Article
Recenzirano
Odprti dostop
We report a previously undescribed inflammatory lesion consisting of deposition of activated complement (C3d and C9neo) in association with major histocompatibility complex type II (MHC2)-positive ...activated microglia in choroid plexus villi exhibiting classical fibrous thickening of the pericapillary filtration membrane. The proportion of villi affected ranged from 5% to 90% in 56 adult subjects with diseases of the CNS and 11 subjects with no preexisting disease of the CNS. In 3 of the 4 children studied, 2% or less of examined villi showed stromal thickening, complement deposition, and the presence of MHC2-positive microglia; in adults, the proportion of villi affected increased with age. Other features of the lesion included loss of capillaries and failure by macrophages to clear extracellular particulate electron-dense material by clathrin-mediated phagocytosis. This choroid plexus lesion may relate pathogenetically to age-related macular degeneration and to Alzheimer disease, 2 other conditions with no known risk factors other than increasing age. All 3 conditions are characterized by the presence of damaged capillaries, inflammatory extracellular aggregates of mixed molecular composition and defective clearance of the deposits by macrophages.
The neuro-otology of Susac syndrome Hardy, Todd A.; Taylor, Rachael L.; Qiu, Jessica ...
Journal of neurology,
12/2020, Letnik:
267, Številka:
12
Journal Article
Recenzirano
Objective
We characterised the clinical and neuro-otological characteristics of patients with Susac syndrome.
Methods
The medical records of 30 patients with Susac syndrome were reviewed for details ...of their clinical presentation and course, neuro-otological symptoms, investigation results including audiology and vestibular function tests, treatment and outcomes.
Results
Our findings demonstrate that 29 of our 30 patients with Susac syndrome developed neuro-otological symptoms such as hearing loss, disequilibrium, tinnitus or vertigo during their disease course. Hearing loss was the most common neuro-otological symptom occurring in 93% of patients. A rising configuration of low-frequency greater than the high-frequency sensorineural hearing loss was the most characteristic finding on audiological testing (37% of reviewed audiograms). Disproportionately poor speech discrimination was identified in 20% of cases, and one case demonstrated a retrocochlear pattern on electrophysiological testing. Four patients required hearing aids and a further two patients required a cochlear implant due to severe hearing loss. Two out of two treated patients had improvements in hearing after the prompt administration of corticosteroids, indicating the potential for recoverable hearing loss if relapses are treated early. Effects on vestibular function were variable in ten patients who were tested, with most showing preservation of function despite significant hearing loss.
Conclusions
Neuro-otological symptoms in Susac syndrome are almost universal. In the correct clinical context, a rising configuration of low to high-frequency sensorineural hearing loss should prompt consideration of Susac syndrome. Treatment of inner ear symptoms in Susac syndrome requires further research as early immunotherapy may be beneficial.
Susac’s syndrome is a rare and debilitating disease characterized by the triad of encephalopathy, branch retinal artery occlusions, and sensorineural hearing loss. All manifestations may not be ...clinically apparent at presentation resulting in delayed diagnosis. Early recognition of the syndrome may prevent disease sequelae such as permanent cognitive, visual, and hearing loss. We present such a case of Susac’s syndrome that was also refractory to conventionally prescribed combination of immunosuppressive treatments including high-dose potent corticosteroids, intravenous cyclophosphamide, methotrexate, plasma exchange, rituximab, and mycophenolate. His disease was stabilized with infliximab in combination with a tapering course of low-dose prednisone. After 2 years of remission with TNF treatment, consideration is being given to ceasing therapy. He has the sequelae of bilateral sensorineural hearing loss but no visual impairment or cognitive deficits on follow-up with neuropsychometric testing. This is the first case report to our knowledge of the successful use of infliximab for a patient with Susac’s syndrome that was necessary following treatment with cyclophosphamide and then rituximab.
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