Is Neuromyelitis Optica Distinct From Multiple Sclerosis?

The neuro-ophthalmological manifestations of NMOSD and MOGAD-a comprehensive review

Optic neuritis (ON) is one of the most frequently seen neuro-ophthalmic causes of vision loss worldwide. Typical ON is often idiopathic or seen in patients with multiple sclerosis, which is well described in the landmark clinical trial, the Optic Neuritis Treatment Trial (ONTT). However, since the completion of the ONTT, there has been the discovery of aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibodies, which are biomarkers for neuromyelitis optica spectrum disorder (NMOSD) and MOG antibody-associated disease (MOGAD), respectively. These disorders are associated with atypical ON that was not well characterised in the ONTT. The severity, rate of recurrence and overall outcome differs in these two entities requiring prompt and accurate diagnosis and management. This review will summarise the characteristic neuro-ophthalmological signs in NMOSD and MOGAD, serological markers and radiographic findings, as well as acute and long-term therapies used for these disorders.

Myelinoclastic diffuse sclerosis (Schilder's disease) is immunologically distinct from multiple sclerosis: results from retrospective analysis of 92 lumbar punctures

BACKGROUND

Myelinoclastic diffuse sclerosis (MDS; also termed Schilder's disease) is a rare inflammatory demyelinating disorder of the central nervous system characterised by demyelination of vast areas of the white matter. It is unclear whether MDS is a variant of multiple sclerosis (MS) or a disease entity in its own right.

OBJECTIVE

To compare the cerebrospinal fluid (CSF) features of MDS with those of MS.

METHODS

Retrospective analysis of the CSF profile of all patients with MDS reported in the medical literature between 1960 and 2018.

RESULTS

The most striking finding was a substantial lack of oligoclonal bands (OCBs) in MDS, which were absent in at least 77% (30/39) of all lumbar punctures (LP) in the total cohort and in 86% in the subgroup of patients with normal very long-chain fatty acid serum ratios (VLCFA). Almost all cases published in the past 15 years were negative for OCBs. These findings are in contrast to MS, in which OCBs are present in up to 98% of cases (p < 0.00001 when compared with reference works in MS; both in adult and in pediatric patients). CSF pleocytosis was absent in at least 79% (46/58) of all LP (p < 0.0001 vs. MS) and in 92% (24/26) of LPs in the VLCFA-tested subgroup. CSF total protein levels were elevated in 56% of all LPs (p < 0.0001 vs. MS) and in 63% of LPs in the VLCFA-tested subgroup and were often higher than in typical MS (> 100 mg/dL in 13/22; up to 220 mg/dL). EBV serum antibodies, which are present in virtually all patients with MS, and the so-called MRZ (measles/rubella/zoster) reaction, a highly specific marker of MS, were absent in all of the few patients tested. In addition, we discuss further differences between MS and MDS, taking into account also Schilder's original comprehensive case description from 1912.

CONCLUSION

In the majority of patients diagnosed with MDS, CSF features differ significantly from those typically found in MS and are more similar to those previously reported in patients with myelin oligodendrocyte glycoprotein-immunoglobulin G (IgG)-positive encephalomyelitis, aquaporin-4-IgG-positive neuromyelitis optica spectrum disorders or Baló's concentric sclerosis. Our data suggest that MDS and MS are immunopathologically distinct entities in the majority of cases.

Passively transferred human NMO-IgG exacerbates demyelination in mouse experimental autoimmune encephalomyelitis

BACKGROUND

Neuromyelitis optica (NMO) is a devastating inflammatory disorder of the optic nerves and spinal cord characterized by frequently recurring exacerbations of humoral inflammation. NMO is associated with the highly specific NMO-IgG biomarker, an antibody that binds the aquaporin-4 water channel. Aquaporin-4 is present on glial endfeet in the central nervous system (CNS). In humans, the NMO-IgG portends more frequent exacerbations and a worse long-term clinical outcome.

METHODS

We tested the longer-term outcome of mice with EAE injected with NMO-IgG and followed them for 60 days. Clinical exams and pathology of the spinal cord and optic nerves were compared to mice that received control human IgG.

RESULTS

Passively transferred human NMO-IgG leads to more severe neurology disability over two months after onset of disease. Clinical worsening is associated with an increased concentration of large demyelinating lesions primarily to subpial AQP4-rich regions of the spinal cord.

CONCLUSIONS

NMO-IgG is pathogenic in the context of EAE in mice.

Review of Animal Models of Neuromyelitis Optica

Neuromyelitis optica (NMO) is a recurrent neuroinflammatory disease of the optic nerves and spinal cord associated with the anti-aquaporin-4 (AQP4) antibody biomarker, NMO-IgG. As clinical and scientific research interest in NMO grows, the need for an animal model becomes more urgent. Over the past few years, several groups have developed rodent models that partially represent human NMO disease. Passive transfer of the NMO-IgG is not pathogenic alone, but in certain contexts can recruit granulocytes and lead to increased inflammation. Studies of the cellular immune response against AQP4 have also shed light on the roles of B and T cells in NMO, especially focusing on the role of Th17 T helper cells. This review discusses the contribution of the available NMO animal models to the understanding of NMO disease pathogenesis.

NMO in pediatric patients: brain involvement and clinical expression

OBJECTIVE

To analyze the clinical, neuroimaging characteristics and positivity of the acquaporin water channel (NMO-IgG) in pediatric patients with neuromyelitis optica (NMO). This disorder could have a variable clinical expression. To address such variability, the term NMO spectrum has been suggested.

METHOD

We evaluated six pediatric patients, with a median age of 11 years at the time of the study, with the diagnosis of NMO by the Wingerchuck criteria.

RESULTS

All the cases exhibited bilateral optic neuritis (ON). Four patients had abnormalities on brain MRI from the onset,although only three of them developed symptoms correlated to those lesions during the course of their disorder. NMO-IgG was positive in 80%.

CONCLUSION

Optic neuropathy is the most impaired feature in NMO patients. Brain MRI lesions are not compatible with multiple sclerosis and positivity of the NMO-IgG are also present in NMO pediatric patients, confirming the heterogeneity in the expression of this disorder.

Serum lipoprotein levels in patients with neuromyelitis optica elevated but had little correlation with clinical presentations

OBJECTIVE

To explore the relationship between serum lipoproteins and clinical presentations of NMO patients. To investigate the differences of serum lipoprotein levels between NMO and MS patients.

PATIENTS AND METHODS

Serum lipoprotein levels were measured in 56 NMO patients, 53 MS patients and 54 health subjects. Serum lipoprotein levels in all participants and relevant clinical parameters of NMO patients were investigated. Statistical analyses were performed using the SPSS statistical software.

RESULTS

NMO patients had significantly higher serum cholesterol (TC), triglyceride, low-density lipoprotein cholesterol, apolipoprotein B (apoB), lipoprotein (a) levels and TC/HDL-C, apoB/apoA-1 ratios than health control group. NMO patients had significantly higher serum apoB level and apoB/apoA-1 ratio than MS patients. There was little correlation between serum lipoproteins and NMO presentations.

CONCLUSION

The elevated lipoprotein levels in NMO patients could be just secondary changes with limited value in clinical prediction. However, elevated apoB level and apoB/apoA-1 ratio in NMO might indicate severer disability and might provide some useful information in the differential diagnosis with MS.

Spectrum of pediatric neuromyelitis optica

OBJECTIVE

Our goal was to describe the spectrum of clinical phenotypes, laboratory and imaging features, and treatment in pediatric patients with neuromyelitis optica.

PATIENTS AND METHODS

The study consisted of a retrospective chart review of patients followed in a pediatric multiple sclerosis center with a diagnosis of neuromyelitis optica spectrum disorder.

RESULTS

Nine patients with neuromyelitis optica spectrum disorders were included, all of whom were female. There were 4 black children, 2 Latin American children, 2 white children, and 1 child of mixed Latin American/white heritage. Median age at initial attack was 14 years (range: 1.9-16 years). Median disease duration was 4 years (range: 0.6-9 years). Tests for neuromyelitis optica immunoglobulin G were positive for 7 patients. Eight patients had transverse myelitis and optic neuritis, and 1 patient had longitudinally extensive transverse myelitis without optic neuritis but had a positive neuromyelitis optica immunoglobulin G antibody titer. Cerebral involvement on MRI was found in all subjects, 5 of whom were symptomatic with encephalopathy, seizures, hemiparesis, aphasia, vomiting, or hiccups. Immunosuppressive therapy reduced attack frequency and progression of disability.

CONCLUSIONS

Pediatric neuromyelitis optica has a diverse clinical presentation and may be difficult to distinguish from multiple sclerosis in the early stages of the disease. The recognition of the broad spectrum of this disease to include signs and symptoms of brain involvement is aided by the availability of a serum biomarker: neuromyelitis optica immunoglobulin G. Early diagnosis and immunosuppresive treatment may help to slow the accumulation of severe disability.

Multiple sclerosis findings in the spinal cord

The spinal cord is commonly affected by acute demyelinating lesions, chronic tissue loss and atrophy in multiple sclerosis, and is a clinically eloquent site. Historically, however, more attention has been focussed on the analysis and contribution of brain lesions. In this review, we discuss some of the key findings from MRI analysis and histopathological examination of the spinal cord, and how they relate to the clinical characteristics of this common and disabling disease.