New evidence and consensus has led to further revision of the McDonald Criteria for diagnosis of multiple sclerosis. The use of imaging for demonstration of dissemination of central nervous system lesions in space and time has been simplified, and in some circumstances dissemination in space and time can be established by a single scan. These revisions simplify the Criteria, preserve their diagnostic sensitivity and specificity, address their applicability across populations, and may allow earlier diagnosis and more uniform and widespread use.

/pdf/diagnostic-criteria-for-multiple-sclerosis-2010-revisions-to-24iph50480.pdf

Diagnostic criteria for multiple sclerosis: 2010 Revisions to the McDonald criteria

New diagnostic criteria for multiple sclerosis integrating magnetic resonance image assessment with clinical and other paraclinical methods were introduced in 2001. The "McDonald Criteria" have been extensively assessed and used since 2001. New evidence and consensus now strengthen the role of these criteria in the multiple sclerosis diagnostic workup to demonstrate dissemination of lesions in time, to clarify the use of spinal cord lesions, and to simplify diagnosis of primary progressive disease. The 2005 Revisions to the McDonald Diagnostic Criteria for MS should simplify and speed diagnosis, whereas maintaining adequate sensitivity and specificity.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/ana.20703

Diagnostic criteria for multiple sclerosis: 2005 revisions to the "McDonald Criteria".

The 2010 McDonald criteria for the diagnosis of multiple sclerosis are widely used in research and clinical practice. Scientific advances in the past 7 years suggest that they might no longer provide the most up-to-date guidance for clinicians and researchers. The International Panel on Diagnosis of Multiple Sclerosis reviewed the 2010 McDonald criteria and recommended revisions. The 2017 McDonald criteria continue to apply primarily to patients experiencing a typical clinically isolated syndrome, define what is needed to fulfil dissemination in time and space of lesions in the CNS, and stress the need for no better explanation for the presentation. The following changes were made: in patients with a typical clinically isolated syndrome and clinical or MRI demonstration of dissemination in space, the presence of CSF-specific oligoclonal bands allows a diagnosis of multiple sclerosis; symptomatic lesions can be used to demonstrate dissemination in space or time in patients with supratentorial, infratentorial, or spinal cord syndrome; and cortical lesions can be used to demonstrate dissemination in space. Research to further refine the criteria should focus on optic nerve involvement, validation in diverse populations, and incorporation of advanced imaging, neurophysiological, and body fluid markers.

/pdf/diagnosis-of-multiple-sclerosis-2017-revisions-of-the-55ct02l5o1.pdf

Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria

Neuromyelitis optica (NMO) is an inflammatory CNS syndrome distinct from multiple sclerosis (MS) that is associated with serum aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). Prior NMO diagnostic criteria required optic nerve and spinal cord involvement but more restricted or more extensive CNS involvement may occur. The International Panel for NMO Diagnosis (IPND) was convened to develop revised diagnostic criteria using systematic literature reviews and electronic surveys to facilitate consensus. The new nomenclature defines the unifying term NMO spectrum disorders (NMOSD), which is stratified further by serologic testing (NMOSD with or without AQP4-IgG). The core clinical characteristics required for patients with NMOSD with AQP4-IgG include clinical syndromes or MRI findings related to optic nerve, spinal cord, area postrema, other brainstem, diencephalic, or cerebral presentations. More stringent clinical criteria, with additional neuroimaging findings, are required for diagnosis of NMOSD without AQP4-IgG or when serologic testing is unavailable. The IPND also proposed validation strategies and achieved consensus on pediatric NMOSD diagnosis and the concepts of monophasic NMOSD and opticospinal MS.

https://n.neurology.org/content/neurology/85/2/177.full.pdf

International consensus diagnostic criteria for neuromyelitis optica spectrum disorders

A serum autoantibody marker of neuromyelitis optica : distinction from multiple sclerosis

Background: The authors previously proposed diagnostic criteria for neuromyelitis optica (NMO) that facilitate its distinction from prototypic multiple sclerosis (MS) However, some patients with otherwise typical NMO have additional symptoms not attributable to optic nerve or spinal cord inflammation or have MS-like brain MRI lesions Furthermore, some patients are misclassified as NMO by the authors’ earlier proposed criteria despite having a subsequent course indistinguishable from prototypic MS A serum autoantibody marker, NMO-IgG, is highly specific for NMO The authors propose revised NMO diagnostic criteria that incorporate NMO-IgG status Methods: Using final clinical diagnosis (NMO or MS) as the reference standard, the authors calculated sensitivity and specificity for each criterion and various combinations using a sample of 96 patients with NMO and 33 with MS The authors used likelihood ratios and logistic regression analysis to develop the most practical and informative diagnostic model Results: Fourteen patients with NMO (146%) had extra-optic-spinal CNS symptoms NMO-IgG seropositivity was 76% sensitive and 94% specific for NMO The best diagnostic combination was 99% sensitive and 90% specific for NMO and consisted of at least two of three elements: longitudinally extensive cord lesion, onset brain MRI nondiagnostic for MS, or NMO-IgG seropositivity Conclusions: The authors propose revised diagnostic criteria for definite neuromyelitis optica (NMO) that require optic neuritis, myelitis, and at least two of three supportive criteria: MRI evidence of a contiguous spinal cord lesion 3 or more segments in length, onset brain MRI nondiagnostic for multiple sclerosis, or NMO-IgG seropositivity CNS involvement beyond the optic nerves and spinal cord is compatible with NMO

https://n.neurology.org/content/neurology/66/10/1485.full.pdf

Revised diagnostic criteria for neuromyelitis optica

Devic's disease [neuromyelitis optica (NMO)] is an idiopathic inflammatory demyelinating disease of the CNS, characterized by attacks of optic neuritis and myelitis. The mechanisms that result in selective localization of inflammatory demyelinating lesions to the optic nerves and spinal cord are unknown. Serological and clinical evidence of B cell autoimmunity has been observed in a high proportion of patients with NMO. The purpose of this study was to investigate the importance of humoral mechanisms, including complement activation, in producing the necrotizing demyelination seen in the spinal cord and optic nerves. Eighty-two lesions were examined from nine autopsy cases of clinically confirmed Devic's disease. Demyelinating activity in the lesions was immunocytochemically classified as early active (21 lesions), late active (18 lesions), inactive (35 lesions) or remyelinating (eight lesions) by examining the antigenic profile of myelin degradation products within macrophages. The pathology of the lesions was analysed using a broad spectrum of immunological and neurobiological markers, and lesions were defined on the basis of myelin protein loss, the geography and extension of plaques, the patterns of oligodendrocyte destruction and the immunopathological evidence of complement activation. The pathology was identical in all nine patients. Extensive demyelination was present across multiple spinal cord levels, associated with cavitation, necrosis and acute axonal pathology (spheroids), in both grey and white matter. There was a pronounced loss of oligodendrocytes within the lesions. The inflammatory infiltrates in active lesions were characterized by extensive macrophage infiltration associated with large numbers of perivascular granulocytes and eosinophils and rare CD3(+) and CD8(+) T cells. There was a pronounced perivascular deposition of immunoglobulins (mainly IgM) and complement C9neo antigen in active lesions associated with prominent vascular fibrosis and hyalinization in both active and inactive lesions. The extent of complement activation, eosinophilic infiltration and vascular fibrosis observed in the Devic NMO cases is more prominent compared with that in prototypic multiple sclerosis, and supports a role for humoral immunity in the pathogenesis of NMO. Based on this study, future therapeutic strategies designed to limit the deleterious effects of complement activation, eosinophil degranulation and neutrophil/macrophage/microglial activation are worthy of further investigation.

/pdf/a-role-for-humoral-mechanisms-in-the-pathogenesis-of-devic-s-28ehcynvgi.pdf

A role for humoral mechanisms in the pathogenesis of Devic’s neuromyelitis optica

Background: Autoantibody specific for the aquaporin-4 astrocytic water channel is restricted to serum and CSF of patients with neuromyelitis optica (NMO) and related CNS inflammatory demyelinating disorders (relapsing optic neuritis and longitudinally extensive transverse myelitis). NMO-typical lesions are distinct from MS-typical lesions. Aquaporin-4 is lost selectively at vasculocentric sites of edema/inflammation coinciding with focal deposits of immunoglobulins (Ig) G, M, and terminal complement products, with and without myelin loss. Evidence for antigen-specific autoantibody pathogenicity is lacking. Methods: We used confocal microscopy and flow cytometry to evaluate the selectivity and immunopathological consequences of Ig binding to surface epitopes of living target cells expressing aquaporin-4 fused at its cytoplasmic N-terminus with GFP. We tested serum, IgG-enriched and IgG-depleted serum fractions, and CSF from patients with NMO, neurologic control patients, and healthy subjects. We also analyzed aquaporin-4 immunoreactivity in myelinated adult mouse optic nerves and spinal cord, and plasma cell Ig isotypes in archived brain tissue from an NMO patient. Results: Serum IgG from patients with NMO binds to the extracellular domain of aquaporin-4; it is predominantly IgG 1 , and it initiates two potentially competing outcomes, aquaporin-4 endocytosis/degradation and complement activation. Serum and CSF lack aquaporin-4-specific IgM, and plasma cells in CNS lesions of NMO contain only IgG. Paranodal astrocytic endfeet highly express aquaporin-4. Conclusions: NMO patients’ serum IgG has a selective pathologic effect on cell membranes expressing aquaporin-4. IgG targeting astrocytic processes around nodes of Ranvier could initiate demyelination.

Pathogenic potential of IgG binding to water channel extracellular domain in neuromyelitis optica

Neuromyelitis optica (NMO)-immunoglobulin G (IgG) is a clinically validated serum biomarker that distinguishes relapsing central nervous system (CNS) inflammatory demyelinating disorders related to NMO from multiple sclerosis. This autoantibody targets astrocytic aquaporin-4 (AQP4) water channels. Clinical, radiological, and immunopathological data suggest that NMO-IgG might be pathogenic. Characteristic CNS lesions exhibit selective depletion of AQP4, with and without associated myelin loss; focal vasculocentric deposits of IgG, IgM, and complement; prominent edema; and inflammation. The effect of NMO-IgG on astrocytes has not been studied. In this study, we demonstrate that exposure to NMO patient serum and active complement compromises the membrane integrity of CNS-derived astrocytes. Without complement, astrocytic membranes remain intact, but AQP4 is endocytosed with concomitant loss of Na+-dependent glutamate transport and loss of the excitatory amino acid transporter 2 (EAAT2) . Our data suggest that EAAT2 and AQP4 exist in astrocytic membranes as a macromolecular complex. Transport-competent EAAT2 protein is up-regulated in differentiating astrocyte progenitors and in nonneural cells expressing AQP4 transgenically. Marked reduction of EAAT2 in AQP4-deficient regions of NMO patient spinal cord lesions supports our immunocytochemical and immunoprecipitation data. Thus, binding of NMO-IgG to astrocytic AQP4 initiates several potentially neuropathogenic mechanisms: complement activation, AQP4 and EAAT2 down-regulation, and disruption of glutamate homeostasis.

https://rupress.org/jem/article-pdf/205/11/2473/1196193/jem_20081241.pdf

C. F. Lucchinetti

Papers

A serum autoantibody marker of neuromyelitis optica : distinction from multiple sclerosis

Revised diagnostic criteria for neuromyelitis optica

A role for humoral mechanisms in the pathogenesis of Devic’s neuromyelitis optica

Pathogenic potential of IgG binding to water channel extracellular domain in neuromyelitis optica

Aquaporin-4–binding autoantibodies in patients with neuromyelitis optica impair glutamate transport by down-regulating EAAT2