International consensus diagnostic criteria for neuromyelitis optica spectrum disorders

What's new in neuromyelitis optica? A short review for the clinical neurologist

The evolution of neuromyelitis optica spectrum disorder (NMOSD) from a rare, incurable and misunderstood disease with almost universally poor outcomes to its present state in just over a decade is unprecedented in neurology and possibly in medicine. Our knowledge of NMOSD biology has led to the recognition of wider phenotypes, new disease mechanisms, and thus clinical trials of new and effective treatments. This article aims to update readers on the recent developments in NMOSD with particular emphasis on clinical advances, the 2015 diagnostic criteria, biomarkers, imaging, and therapeutic interventions.

Clinical Features of Patients with Multiple Sclerosis and Neuromyelitis Optica Spectrum Disorders

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) was long believed to be an aggressive form of multiple sclerosis (MS). This study aimed to describe the clinical features of patients with MS and NMOSD to assist in differential diagnoses in clinical practice.

METHODS

Data including the patients' serum and cerebrospinal fluid (CSF) tests, image findings, and clinical information from 175 patients with MS or NMOSD at Xuanwu Hospital, Capital Medical University from November 2012 to May 2014 were collected and analyzed retrospectively. An enzyme-linked immunosorbent assay was performed to detect the myelin oligodendrocyte glycoprotein (MOG) autoantibodies in CSF and serum. Cell-based assays were used to detect aquaporin-4-antibody (AQP4-Ab). The Chi-square test was used to compare the categorical variables. Wilcoxon rank sum test was performed to analyze the continuous variables.

RESULTS

Totally 85 MS patients (49%) and 90 NMOSD patients (51%) were enrolled, including 124 (71%) women and 51 (29%) men. Fewer MS patients (6%) had autoimmune diseases compared to NMOSD (19%) (Δ2 = 6.9, P < 0.01). Patients with NMOSD had higher Expanded Disability Status Scale scores (3.5 [3]) than MS group (2 [2]) (Z = -3.69, P < 0.01). The CSF levels of white cell count and protein in both two groups were slightly elevated than the normal range, without significant difference between each other. Positivity of serum AQP4-Ab in NMOSD patients was higher than that in MS patients (MS: 0, NMOSD: 67%; Δ2 = 63.9, P < 0.01). Oligoclonal bands in CSF among NMOSD patients were remarkably lower than that among MS (MS: 59%, NMOSD: 20%; Δ2 = 25.7, P < 0.01). No significant difference of MOG autoantibodies was found between the two groups.

CONCLUSION

The different CSF features combined with clinical, magnetic resonance imaging, and serum characteristics between Chinese patients with MS and NMOSD could assist in the differential diagnosis.

Interleukin-6 analysis of 572 consecutive CSF samples from neurological disorders: A special focus on neuromyelitis optica

BACKGROUND

Elevation of cerebrospinal fluid (CSF) interleukin (IL)-6 has been reported in various neurological disorders but has never been systematically analyzed. Our main objectives are to compare the CSF IL-6 levels among various neurological disorders and to evaluate the significance of CSF IL-6 measurements for the diagnosis of neuromyelitis optica (NMO).

METHODS

We retrospectively investigated the IL-6 levels of 572 consecutive CSF samples in patients with various neurological disorders. Additionally, the associations between clinical manifestations in NMO patients and CSF IL-6 levels were closely investigated.

RESULTS

Among the neurological disorders, patients with NMO had the highest CSF IL-6 level. Receiver operating characteristic analysis found the optimal cutoff CSF IL-6 value for diagnosing NMO as 7.8pg/ml, and the sensitivity and specificity were 0.7317 and 0.7694, respectively. In NMO, CSF IL-6 levels were correlated with the length of the spinal cord lesion and anti-aquaporin-4 antibody-positivity and decreased after treatment.

CONCLUSION

CSF IL-6 can be high in various inflammatory and non-inflammatory CNS disorders, but its upregulation appears to be the most remarkable in NMO.

Large-Scale in-House Cell-Based Assay for Evaluating the Serostatus in Patients with Neuromyelitis Optica Spectrum Disorder Based on New Diagnostic Criteria

BACKGROUND AND PURPOSE

The detection of aquaporin 4-IgG (AQP4-IgG) is now a critical diagnostic criterion for neuromyelitis optica spectrum disorder (NMOSD). To evaluate the serostatus of NMOSD patients based on the 2015 new diagnostic criteria using a new in-house cell-based assay (CBA).

METHODS

We generated a stable cell line using internal ribosome entry site-containing bicistronic vectors, which allow the simultaneous expression of two proteins (AQP4 and green fluorescent protein) separately from the same RNA transcript. We performed in-house CBA using serum from 386 patients: 178 NMOSD patients diagnosed according to the new diagnostic criteria without AQP4-IgG, 63 high risk NMOSD patients presenting 1 of the 6 core clinical characteristics of NMOSD but not fulfilling dissemination in space, and 145 patients with other neurological diseases, including 66 with multiple sclerosis. The serostatus of 111 definite and high risk NMOSD patients were also tested using a commercial CBA kit with identical serum to evaluate the correlation between the 2 methods. All assays were performed by two independent and blinded investigators.

RESULTS

Our in-house assay yielded a specificity of 100% and sensitivities of 80% (142 of 178) and 76% (48 of 63) when detecting definite- and high risk NMOSD patients, respectively. The comparison with the commercial CBA kit revealed a correlation for 102 of the 111 patients: no correlation was present in 7 patients who were seronegative using the commercial method but seropositive using the in-house method, and in 2 patients who were seropositive using the commercial method but seronegative using the in-house method.

CONCLUSIONS

These results demonstrate that our in-house CBA is a highly specific and sensitive method for detecting AQP4-IgG in NMOSD patients.

Combined brain and anterior visual pathways' MRIs assist in early identification of neuromyelitis optica spectrum disorder at onset of optic neuritis

Acute optic neuritis (ON) is the initial presentation in half of neuromyelitis optica spectrum disorder (NMO-SD) cases. Our objective was to evaluate accuracy of combined MRIs of the anterior visual pathways and of the brain to correctly identify NMO-SD among patients with acute ON. We performed a retrospective study on patients with acute ON in NMO-SD (16 episodes) and first-event non-NMO-SD (32 episodes). All MRIs included exams of the brain and anterior visual pathways using T2-weighted and post-gadolinium T1-weighted coronal thin slices. Images were reviewed by a neuroradiologist who was blinded to the final diagnosis. There were no multiple sclerosis (MS)-like lesions with dissemination in space (DIS) with NMO-SD (0 vs. 53%, p < 0.01). Non-NMO-SD ON usually spared the chiasma (3 vs. 44%, p < 0.01) and the optic tracts (0 vs. 19%, p < 0.01). Optic nerve lesions were longer [median (range) 26 mm (14-64) vs. 13 mm [8-36], p < 0.01] and the number of segments involved higher (3 [1-8] vs. 1 [1-4], p < 0.01) in NMO-SD. Bilateral optic nerve involvement, or involvement of ≥3 segments, or involvement of the chiasma, or optic tracts in the absence of MS-like lesions with DIS were suggestive of NMO-SD with a sensitivity of 69% (CI 95% 41-89) and a specificity of 97% (CI 95% 84-99) (p < 0.01). Combining brain and anterior visual pathways' MRIs seems efficient for detecting acute ON patients who are at high risk for NMO-SD.

Ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorders

OBJECTIVE

We assessed the frequency and characteristics of ring-enhancing spinal cord lesions in neuromyelitis optica spectrum disorder (NMOSD) myelitis and myelitis of other cause.

METHODS

We reviewed spinal cord MRIs for ring-enhancing lesions from 284 aquaporin-4 (AQP4)-IgG seropositive patients at Mayo Clinic from 1996 to 2014. Inclusion criteria were as follows: (1) AQP4-IgG seropositivity, (2) myelitis attack and (3) MRI spinal cord demonstrating ring-enhancement. We identified two groups of control patients with: (1) longitudinally extensive myelopathy of other cause (n=66) and (2) myelitis in the context of a concurrent or subsequent diagnosis of multiple sclerosis (MS) from a population-based cohort (n=30).

RESULTS

Ring-enhancement was detected in 50 of 156 (32%) myelitis episodes in 41 patients (83% single; 17% multiple attacks). Ring-enhancement was noted on sagittal and axial images in 36 of 43 (84%) ring enhancing myelitis episodes and extended a median of two vertebral segments (range, 1-12); in 21 of 48 (44%) ring enhancing myelitis episodes, the ring extended greater than or equal to three vertebrae. Ring-enhancement was accompanied by longitudinally extensive (greater than or equal to three vertebral segments) T2-hyperintensity in 44 of 50 (88%) ring enhancing myelitis episodes. One case of a spinal cord biopsy during ring-enhancing myelitis revealed tissue vacuolation and loss of AQP4 immunoreactivity with preserved axons. The clinical characteristics of ring-enhancing myelitis episodes did not differ from non-ring-enhancing episodes. Ring-enhancing spinal cord lesions were more common in NMOSD than other causes of longitudinally extensive myelopathy (50/156 (32%) vs 0/66 (0%); p≤0.001) but did not differ between NMOSD and MS (50/156 (32%) vs 6/30 (20%); p=0.20).

CONCLUSIONS

Spinal cord ring-enhancement accompanies one-third of NMOSD myelitis episodes and distinguishes NMOSD from other causes of longitudinally extensive myelopathies but not from MS.

Pseudotumoral brain lesions: MRI review

Single or multiple space-occupying lesions on brain MRI, with or without contrast enhancement and/or perilesional oedema, evoke a neoplastic origin. However, a multitude of non-neoplastic disorders can simulate cerebral neoplasia. In this review, we will discuss the MRI characteristics of non-neoplastic disorders that can mimic cerebral neoplasia. Distinguishing MRI characteristics are discussed for each of these non-neoplastic disorders.

Pediatric Autoimmune Epileptic Encephalopathies

Pediatric autoimmune epileptic encephalopathies are predominantly characterized by the presence of autoantibodies to the surface of neuronal proteins, for example, N-methyl-d-aspartate (NMDA) receptor antibodies, but also include diseases with non-cell surface antibodies (eg, anti-Hu, glutamic-acid decarboxylase antibodies). In some cases with distinct clinical and para-clinical features, an autoimmune epileptic encephalopathy can be diagnosed without the presence of an antibody and will also respond favorably to immunotherapy. In this review, we summarize the common presentations of pediatric autoimmune epileptic encephalopathies, treatments, and outcomes, and report recent findings in the field of epilepsy, encephalopathy, and the immune system.

Different Phenotypes at Onset in Neuromyelitis Optica Spectrum Disorder Patients with Aquaporin-4 Autoimmunity

Background

Although rare, brain abnormalities without optic neuritis (ON) or transverse myelitis (TM) diagnosed with neuromyelitis optica spectrum disorder (NMOSD) have been reported in patients positive for the aquaporin-4 (AQP4) antibody.

Objective

To analyze demographic and clinical differences among NMOSD patients without ON or TM, those with either ON or TM, and patients with simultaneous ON and TM at disease onset.

Methods

In this retrospective study, patients who were positive for the AQP4 antibody, as detected using a cell-based assay, at the Second Affiliated Hospital of Guangzhou Medical University in China were recruited. Demographic and clinical data were obtained from each patient’s medical record.

Results

A total of 292 patients were included in this study and were divided into four subgroups based on their initial manifestations: (i) NMOSD without ON or TM (NMOSD-ON⁻TM⁻, n = 70); (ii) NMOSD with ON (NMOSD-ON⁺, n = 95); (iii) NMOSD with TM (NMOSD-TM⁺, n = 116); and (iv) simultaneous ON and TM [neuromyelitis optica (NMO), n = 11]. We found that age at onset was lower in the NMOSD-ON⁻TM⁻ group than that in the other groups. The interval from the first episode to relapse was shorter in the NMOSD-ON⁻TM⁻ group than that in NMOSD-TM⁺ group. Cerebral spinal fluid white cell counts and protein levels were significantly higher in the NMOSD-ON⁻TM⁻ group than those in the other groups. Lower Expanded Disability Status Scale scores were observed in the NMOSD-ON⁻TM⁻ group. Brain abnormalities, including in area postrema and hemisphere lesions, were more frequent in the NMOSD-ON⁻TM⁻ group. Kaplan–Meier analysis showed that patients in the NMOSD-ON⁻TM⁻ group experienced earlier relapse than those in other groups. Conversion to NMO in the NMOSD-ON⁺ group was greater than that in the other groups. Only 14 patients (4.8%, 14/292) had pure brain abnormalities, of which 12 had disease duration of several more years and 8 (57.1%) experienced relapses.

Conclusion

NMOSD patients with different initial manifestations present with significant differences in clinical features during follow-up. Patients with long-term AQP4 autoimmunity in the brain in the absence of ON or TM are not common.

[A case of neuromyelitis optica spectrum disorder (NMOSD) with Sjögren's syndrome manifested only brain involvement by preceding parotitis]

A 33 year-old woman presented with intentional incontinence, motor aphasia, supranuclear gaze palsy, and spasticity after parotitis. Brain magnetic resonance images (MRI) showed abnormal signaling in long corticospinal tract involving internal capsules and cerebral peduncles, middle cerebellar peduncle, and frontal subcortical white matter lesions. She had a long history of dry eye and mouth. Immunoserological study showed that she was positive for anti-SS-A, aquaporin 4 (AQP4), and AQP5 antibodies. She clinically showed not only Sjögren's syndrome but also neuromyelitis optica spectrum disorder (NMOSD) without optic neuritis or myelitis. She responded to steroid followed by plasma exchange dramatically. Thereafter, the relapse of brain lesion was once detected while tapering of steroid, but her symptoms have been stable for several years after administration of immunosuppressant. This case suggested that salivary gland inflammation might be associated with the pathogenesis of NMOSD.

Normal-appearing white matter demyelination in neuromyelitis optica spectrum disorder

BACKGROUND AND PURPOSE

Increasing evidence suggests the presence of demyelination in the normal-appearing white matter (NAWM) of patients with neuromyelitis optica spectrum disorder (NMOSD). The objective was to determine the presence of subclinical demyelination in the NAWM of patients with NMOSD using myelin water imaging (MWI).

METHODS

Whole brain and regions-of-interest (ROIs) analyses, including the centrum semiovale, corona radiata, genu and splenium of the corpus callosum, and optic radiation, were conducted in the NAWM of 28 NMOSD patients and 18 healthy controls (HCs) using two MWI modalities: conventional MWI and direct visualization of short transverse relaxation time component (ViSTa) MWI.

RESULTS

Conventional myelin water fractions (MWFs) of the global NAWM and three ROIs (centrum semiovale, corona radiata, and genu of the corpus callosum) were slightly lower in NMOSD patients than in HCs, although not statistically significant. On the other hand, ViSTa MWF values of the global NAWM and all ROIs except the genu of the corpus callosum were significantly lower in NMOSD patients relative to HCs. In particular, the MWF in the optic radiation was significantly reduced in NMOSD patients relative to HCs in both MWI methods, even in patients who had no brain involvement. Additionally, patients with optic neuritis showed lower MWF than patients without optic neuritis and a negative correlation was identified between the MWF of the optic radiation and visual functional system score.

CONCLUSIONS

This study identified the presence of widespread demyelination in the NAWM of NMOSD patients and highlighted the optic radiation as a site of marked demyelination.

Fast multiple sclerosis progression in North Africans

Objective:

To compare multiple sclerosis (MS) disability progression among North Africans (NAs) living in France (NAF) and in Tunisia (NAT) and Caucasian patients born and living in France (CF).

Methods:

Patients with MS admitted to the day hospital in the Neurology Department at Pitié-Salpêtrière Hospital (France) and Razi Hospital (Tunisia) were questioned on their place of birth and the place of birth of their parents. To compare delay to outcomes, log-rank tests were used. Univariate and multivariate Cox models were used to determine factors influencing time to Expanded Disability Status Scale (EDSS) 6.

Results:

We consecutively included 462 patients: 171 CF, 151 NAT, and 140 NAF. Sex ratio, disease forms, and delay from disease onset to diagnosis were similar between the groups. NAF differed from other groups, with a shorter median time to reach EDSS 3, 4, and 6, and a more frequent incomplete recovery after first relapse (p < 0.0001). Furthermore, the NA second-generation group showed the youngest median age at onset (26.5 ± 8.8 years, p = 0.001), the shortest median time to EDSS 6 in relapsing-remitting patients, and an increased mean number of relapses during the first 5 years of the disease (6.1 ± 3.7, p = 0.01) compared to CF. The Cox proportional hazard models demonstrate that (1) NA ethnicity is a significant predictor of fast progression even when adjusting for major covariates and (2) treatment did not influence the models.

Conclusion:

Our study further supports severity of MS in NAs and unravels the particular severity in NAs living in France, mainly for the second generation.

Microstructural visual system changes in AQP4-antibody-seropositive NMOSD

Objective:

To trace microstructural changes in patients with aquaporin-4 antibody (AQP4-ab)-seropositive neuromyelitis optica spectrum disorders (NMOSDs) by investigating the afferent visual system in patients without clinically overt visual symptoms or visual pathway lesions.

Methods:

Of 51 screened patients with NMOSD from a longitudinal observational cohort study, we compared 6 AQP4-ab–seropositive NMOSD patients with longitudinally extensive transverse myelitis (LETM) but no history of optic neuritis (ON) or other bout (NMOSD-LETM) to 19 AQP4-ab–seropositive NMOSD patients with previous ON (NMOSD-ON) and 26 healthy controls (HCs). Foveal thickness (FT), peripapillary retinal nerve fiber layer (pRNFL) thickness, and ganglion cell and inner plexiform layer (GCIPL) thickness were measured with optical coherence tomography (OCT). Microstructural changes in the optic radiation (OR) were investigated using diffusion tensor imaging (DTI). Visual function was determined by high-contrast visual acuity (VA). OCT results were confirmed in a second independent cohort.

Results:

FT was reduced in both patients with NMOSD-LETM (p = 3.52e⁻¹⁴) and NMOSD-ON (p = 1.24e⁻¹⁶) in comparison with HC. Probabilistic tractography showed fractional anisotropy reduction in the OR in patients with NMOSD-LETM (p = 0.046) and NMOSD-ON (p = 1.50e⁻⁵) compared with HC. Only patients with NMOSD-ON but not NMOSD-LETM showed neuroaxonal damage in the form of pRNFL and GCIPL thinning. VA was normal in patients with NMOSD-LETM and was not associated with OCT or DTI parameters.

Conclusions:

Patients with AQP4-ab–seropositive NMOSD without a history of ON have microstructural changes in the afferent visual system. The localization of retinal changes around the Müller-cell rich fovea supports a retinal astrocytopathy.

Impact of the anti-aquaporin-4 autoantibody on inner retinal structure, function and structure-function associations in Japanese patients with optic neuritis

PURPOSE

An autoantibody against aquaporin-4 (AQP4 Ab) is highly specific for neuromyelitis optica spectrum disorder and plays a pathogenic role in this disease. The purpose of this study was to investigate the impact of AQP4 Ab on inner retinal structure, function, and the structure-function relationships in eyes with optic neuritis.

METHODS

Thirty five eyes from 25 cases who had received visual function tests and RTVue optical coherence tomography (OCT) measurement at least six months after the latest episode of optic neuritis were enrolled. Patients with multiple sclerosis were excluded. AQP4 Ab was measured using a cell-based assay. Visual acuity, mean deviation (MD) of the Humphrey visual field SITA standard 30-2 tests, retinal nerve fiber layer (RNFL), ganglion cell complex (GCC) thicknesses, and other clinical variables were compared between the AQP4 Ab-positive and -negative groups. Parameters associated with visual functions were evaluated by generalized estimating equation (GEE) models.

RESULTS

The AQP4 Ab-positive group (20 eyes from 12 cases) had a higher proportion of bilateral involvement and longer duration of follow-up than the AQP4 Ab-negative group (15 eyes from 13 cases). Linear mixed effect models revealed worse MD and visual acuity in AQP4 Ab-positive eyes than those in AQP4 Ab-negative eyes after adjusting for within-patient inter-eye dependence, whereas there were no differences in RNFL and GCC thickness between the two groups. In seropositive eyes, GEE regression analyses revealed that depending on age and the number of recurrences of ON episodes, OCT parameters correlated strongly with MD and more weakly with visual acuity.

CONCLUSIONS

Reductions in RNFL and GCC thickness were proportional to the visual field defect in eyes with AQP4 Ab but not in eyes without AQP4 Ab. The presence of AQP4 Ab probably plays a critical role in retinal ganglion cell loss in optic neuritis.

Upregulation of Bcl-2 and Its Promoter Signals in CD4+ T Cells during Neuromyelitis Optica Remission

The homeostatic balance between production and elimination of CD4+ T cells in peripheral blood plays an important role in patients with neuromyelitis optica (NMO). The objective of the present study was to evaluate the anti-apoptosis genes Bcl-2 and its promoter signal (nuclear factor kappa-light-chain-enhancer of activated B cells, NFκB) in CD4+ T cells. Healthy subjects (HS, n = 25) and patients with multiple sclerosis (MS) (n = 25) and NMO (n = 30) in remission were consecutively enrolled in this prospective study between May and December 2015. CD4+ T cells were isolated using magnetic beads coated with anti-CD4 monoclonal antibodies, and gene expression of Bcl-2, NFκB, phosphatidylinositol-4, 5-bisphosphate 3-kinase/protein kinase B (PI3K/Akt), and MAP kinase kinase kinase 7 (MAP3K7) was measured by real-time reverse transcription-polymerase chain reaction (rt-PCR). Cytokines of tumor necrosis factor (TNF)-α and interleukin (IL)-1β were detected using human cytokine multiplex assay. Bcl-2 and NFκB gene expressions were elevated in NMO patients (1.63 ± 0.25; 2.35 ± 0.25) compared with those of HS (0.90 ± 0.11; 1.42 ± 0.22) and/or MS patients (1.03 ± 0.18; 1.55 ± 0.20) (P < 0.05). MAP3K7, but not Akt, was increased in NMO patients (1.23 ± 0.18; 1.56 ± 0.22) (P < 0.01) and was a significant factor related to elevated NFκB gene expressions (P < 0.001). On the other hand, IL-1β and TNF-α were also detected in the study and the results showed that both were elevated in NMO patients (23.84 ± 1.81; 56.40 ± 2.45) (P < 0.01; P < 0.05, respectively). We propose that MAP3K7 induced by IL-1β and TNF-α but not Akt promotes NFκB expression and, in turn, prolongs Bcl-2-mediated survival of CD4+ T cells in NMO patients.

Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica (NMO) is clinically characterized by severe optic neuritis and transverse myelitis, but recent studies with anti-aquaporin-4-antibody specific to NMO have revealed that the clinical spectrum is wider than previously thought. International consensus diagnostic criteria propose NMO spectrum disorders (NMOSD) as the term to define the entire spectrum including typical NMO, optic neuritis, acute myelitis, brain syndrome, and their combinations. NMOSD is now divided into anti-aquaporin-4-antibody-seropositive NMOSD and -seronegative NMOSD (or unknown serostatus). MR imaging and optical coherence tomography are indispensable in the diagnosis and evaluation of NMOSD. This article reviews the clinical and MR imaging findings of anti-aquaporin-4-antibody-seropositive and anti-myelin oligodendrocyte glycoprotein-antibody-seropositive NMOSD.

Modulation of Neuroinflammation in the Central Nervous System: Role of Chemokines and Sphingolipids

Neuroinflammation is a process involved in the pathogenesis of different disorders, both autoimmune, such as neuropsychiatric systemic lupus erythematosus, and degenerative, such as Alzheimer's and Parkinson's disease. In the central nervous system, the local milieu is tightly regulated by different mediators, among which are chemoattractant cytokines, also known as chemokines. These small molecules are able to modulate trafficking of immune cells in the course of nervous system development or in response to tissue damage, and different patterns of chemokine molecule and receptor expression have been described in several neuroinflammatory disorders. In recent years, a number of studies have highlighted a pivotal role of sphingolipids in regulating neuroinflammation. Sphingolipids have different functions, among which are the control of leukocyte egress from lymphonodes into inflamed tissues, the expression of various mediators of inflammation and a direct effect on the cells of the central nervous system as regulators of neuroinflammation. In the future, a better knowledge of these two groups of mediators could provide insight into the pathogenesis of neuroinflammatory disorders and could help develop novel diagnostic tools and therapeutic strategies.

Neuromyelitis optica: phenotypic characteristics in a Brazilian case series

ABSTRACT The definition of neuromyelitis optica (NMO) is still evolving. In 2015, the International Panel for NMO Diagnosis was convened to develop revised diagnostic criteria. There have been few studies on NMO in the Brazilian population. Objective To describe the characteristics of 34 Brazilian NMO patients. To evaluate the contribution of the 2015 criteria to the diagnosis of NMO spectrum disorders (NMOSD) in 40 patients with longitudinal extensive transverse myelitis (LEMT). Methods This is a retrospective, descriptive and analytic study. Results Among NMO patients, there was a predominance of women, with onset in the fourth decade of life, and AQP4-IgG seropositivity in 73.5%. The diagnosis of NMOSD was established in 37.5% of LETM patients according to AQP4-IgG positivity and in 5% of LETM patients if the AQP4-IgG result was unknown. Conclusions The characteristics of this series are similar to those of other Western populations. The AQP4-IgG testing assists in the diagnosis of NMOSD.

Brain lesion distribution criteria distinguish MS from AQP4-antibody NMOSD and MOG-antibody disease

IMPORTANCE

Neuromyelitis optica spectrum disorders (NMOSD) can present with very similar clinical features to multiple sclerosis (MS), but the international diagnostic imaging criteria for MS are not necessarily helpful in distinguishing these two diseases.

OBJECTIVE

This multicentre study tested previously reported criteria of '(1) at least 1 lesion adjacent to the body of the lateral ventricle and in the inferior temporal lobe; or (2) the presence of a subcortical U-fibre lesion or (3) a Dawson's finger-type lesion' in an independent cohort of relapsing-remitting multiple sclerosis (RRMS) and AQP4-ab NMOSD patients and also assessed their value in myelin oligodendrocyte glycoprotein (MOG)-ab positive and ab-negative NMOSD.

DESIGN

Brain MRI scans were anonymised and scored on the criteria by 2 of 3 independent raters. In case of disagreement, the final opinion was made by the third rater.

PARTICIPANTS

112 patients with NMOSD (31 AQP4-ab-positive, 21 MOG-ab-positive, 16 ab-negative) or MS (44) were selected from 3 centres (Oxford, Strasbourg and Liverpool) for the presence of brain lesions.

RESULTS

MRI brain lesion distribution criteria were able to distinguish RRMS with a sensitivity of 90.9% and with a specificity of 87.1% against AQP4-ab NMOSD, 95.2% against MOG-ab NMOSD and 87.5% in the heterogenous ab-negative NMOSD cohort. Over the whole NMOSD group, the specificity was 89.7%.

CONCLUSIONS

This study suggests that the brain MRI criteria for differentiating RRMS from NMOSD are sensitive and specific for all phenotypes.

Neurodegeneration in multiple sclerosis and neuromyelitis optica

Multiple sclerosis (MS) and neuromyelitis optica (NMO) are autoimmune demyelinating diseases of the central nervous system (CNS), having distinct immunological and pathological features. They have two pathogenic components, 'inflammation' and 'neurodegeneration', with different degrees of severity and pathogenetic mechanisms. The target antigen of autoimmunity in NMO is the water channel aquaporin-4 (AQP4), and antibodies directed against this antigen result in astrocyte damage. MS is a disease primarily affecting myelin and oligodendrocytes, but thus far, no MS-specific autoantigen has been identified. The distinct inflammatory processes in these diseases may trigger cascades of events leading to disease-specific neurodegeneration. Damage of the CNS tissue appears to be amplified by mechanisms that are in part shared by the two conditions and involve oxidative burst activation in microglia/macrophages, mitochondrial damage and axonal energy failure, Wallerian degeneration and meningeal inflammation. However, they appear to differ regarding the nature of the inflammatory response, the type and extent of cortical injury, and the type of astrocyte reaction and damage. Here, we provide a detailed comparison of the pathology between MS and NMO, which may help to define shared and disease-specific mechanisms of neurodegeneration in these diseases.

The neuromyelitis optica presentation and the aquaporin-4 antibody in HIV-seropositive and seronegative patients in KwaZulu-Natal, South Africa

Background

The association of the anti-aquaporin-4 (AQP-4) water channel antibody with neuromyelitis optica (NMO) syndrome has been described from various parts of the world. There has been no large study describing this association from southern Africa, an HIV endemic area. HIV patients often present with visual disturbance or features of a myelopathy but seldom both either simultaneously or consecutively. We report our experience of NMO in the era of AQP-4 testing in HIV-positive and HIV-negative patients seen in KwaZulu-Natal, South Africa.

Methods

A retrospective chart review was undertaken of NMO cases seen from January 2005 to April 2016 in two neurology units serving a population of 7.1 million adults. The clinical, radiological and relevant laboratory data were extracted from the files and analysed.

Results

There were 12 HIV-positive patients (mean age 33 years), 9 (75%) were women and all 12 were black patients. Of the 17 HIV-negative patients (mean age 32 years), 15 (88%) were women and 10 (59%) were black people. The clinical features in the two groups ranged from isolated optic neuritis, isolated longitudinally extensive myelitis or combinations. Recurrent attacks were noted in six HIV-positive patients and six HIV-negative patients. The AQP-4 antibody was positive in 4/10 (40%) HIV-positive patients and 11/13 (85%) HIV-negative patients. The radiological changes ranged from longitudinal hyperintense spinal cord lesions and long segment enhancing lesions of the optic nerves. Three patients, all HIV-positive, had tumefactive lesions with incomplete ring enhancement.

Conclusion

This study confirms the presence of AQP-4-positive NMO in southern Africa in both HIV-positive and HIV-negative patients. The simultaneous or consecutive occurrence of optic neuritis and myelitis in an HIV-positive patient should alert the clinician to test for the AQP-4 antibody. It is important to recognise this clinical syndrome as specific therapy is available. We further postulate that HIV itself may act as a trigger for an autoimmune process.

No association of AQP4 polymorphisms with neuromyelitis optica and multiple sclerosis

Multiple sclerosis (MS) and neuromyelitis optica (NMO) are inflammatory demyelinating disorders of the central nervous system (CNS). Various genetic and environmental factors have been identified to contribute to etiology of MS and NMO. Aquaporin 4 (AQP4), is the most abundant water channel in CNS. AQP4 is expressed in astrocytes of the brain, spinal cord, optic nerve and supportive cells in sensory organs. In contrast to MS, immunoreactivity of AQP4 is abolished in NMO lesions. However, conflicting results have been reported regarding the association between AQP4 polymorphisms and demyelinating disorders. Considering the ethnic differences of genetic variations, replications in other cohorts are required. In this study, single nucleotide polymorphisms (SNPs) of AQP4 gene in patients with NMO/neuromyelitis optica spectrum disorders (NMOSD), and MS in the Northern Han Chinese population were examined. Six selected AQP4 SNPs were genotyped by high-resolution melting (HRM) method. Compared with healthy control (HC), there was no significant difference of AQP4 allele and genotype frequency in MS or NMO/NMOSD group. This study showed no significant association of common AQP4 SNPs with MS or NMO/NMOSD, strongly suggesting that polymorphisms of AQP4 gene are unlikely to confer MS or NMO/NMOSD susceptibility, at least in Northern Han Chinese population.

Rituximab therapy in pemphigus and other autoantibody-mediated diseases

Rituximab, a monoclonal antibody targeting the B cell marker CD20, was initially approved in 1997 by the United States Food and Drug Administration (FDA) for the treatment of non-Hodgkin lymphoma. Since that time, rituximab has been FDA-approved for rheumatoid arthritis and vasculitides, such as granulomatosis with polyangiitis and microscopic polyangiitis. Additionally, rituximab has been used off-label in the treatment of numerous other autoimmune diseases, with notable success in pemphigus, an autoantibody-mediated skin blistering disease. The efficacy of rituximab therapy in pemphigus has spurred interest in its potential to treat other autoantibody-mediated diseases. This review summarizes the efficacy of rituximab in pemphigus and examines its off-label use in other select autoantibody-mediated diseases.

Retinal Nerve Fiber Layer May Be Better Preserved in MOG-IgG versus AQP4-IgG Optic Neuritis: A Cohort Study

Background

Optic neuritis (ON) in patients with anti-myelin oligodendrocyte glycoprotein (MOG)-IgG antibodies has been associated with a better clinical outcome than anti-aquaporin 4 (AQP4)- IgG ON. Average retinal nerve fiber layer thickness (RNFL) correlates with visual outcome after ON.

Objectives

The aim of this study was to examine whether anti-MOG-IgG ON is associated with better average RNFL compared to anti-AQP4-IgG ON, and whether this corresponds with a better visual outcome.

Methods

A retrospective study was done in a consecutive cohort of patients following anti-AQP4-IgG and anti-MOG-IgG ON. A generalized estimating equation (GEE) models analysis was used to compare average RNFL outcomes in ON eyes of patients with MOG-IgG to AQP4-IgG-positive patients, after adjusting for the number of ON events. The final mean visual field defect and visual acuity were compared between ON eyes of MOG-IgG and AQP4-IgG-positive patients. A correlation between average RNFL and visual function was performed in all study eyes.

Results

Sixteen patients were analyzed; ten AQP4-IgG-positive and six MOG-IgG-positive. The six patients with MOG-IgG had ten ON events with disc edema, five of which were bilateral. In the AQP4-IgG-positive ON events, 1/10 patients had disc edema. Final average RNFL was significantly better in eyes following MOG-IgG-ON (75.33μm), compared to 63.63μm in AQP4-IgG-ON, after adjusting for the number of ON attacks (GEE, p = 0.023). Mean visual field defects were significantly smaller (GEE, p = 0.046) among MOG-IgG positive ON eyes compared to AQP-IgG positive ON eyes, but last visual acuity did not differ between the groups (GEE, p = 0.153). Among all eyes, average RNFL positively correlated with mean visual field defect (GEE, p = 0.00015) and negatively correlated with final visual acuity (GEE, p = 0.00005).

Conclusions

Following ON, RNFL is better preserved in eyes of patients with MOG-IgG antibodies compared to those with AQP4-IgG antibodies, correlating with better visual outcomes.

Deletional tolerance prevents AQP4-directed autoimmunity in mice

Neuromyelitis optica (NMO) is an autoimmune disorder of the central nervous system (CNS) mediated by antibodies to the water channel protein AQP4 expressed in astrocytes. The contribution of AQP4‐specific T cells to the class switch recombination of pathogenic AQP4‐specific antibodies and the inflammation of the blood–brain barrier is incompletely understood, as immunogenic naturally processed T‐cell epitopes of AQP4 are unknown. By immunizing Aqp4^−/− mice with full‐length murine AQP4 protein followed by recall with overlapping peptides, we here identify AQP4(201‐220) as the major immunogenic IA^b‐restricted epitope of AQP4. We show that WT mice do not harbor AQP4(201–220)‐specific T‐cell clones in their natural repertoire due to deletional tolerance. However, immunization with AQP4(201–220) of Rag1^−/− mice reconstituted with the mature T‐cell repertoire of Aqp4^−/− mice elicits an encephalomyelitic syndrome. Similarly to the T‐cell repertoire, the B‐cell repertoire of WT mice is “purged” of AQP4‐specific B cells, and robust serum responses to AQP4 are only mounted in Aqp4^−/− mice. While AQP4(201–220)‐specific T cells alone induce encephalomyelitis, NMO‐specific lesional patterns in the CNS and the retina only occur in the additional presence of anti‐AQP4 antibodies. Thus, failure of deletional T‐cell and B‐cell tolerance against AQP4 is a prerequisite for clinically manifest NMO.

LETM presented with causalgia and ensued by sudden death

BACKGROUND

Longitudinally Extensive Transverse Myelitis LETM is a specific pattern of myelitis wherein at least three continuous vertebral segments are involved. Characteristically, it is a defining feature of neuromyelitis optica NMO. However, it is described in many other etiologies.

CASE PRESENTATION

We present a case of 60 year old male who presented with symptoms and signs of regional sympathetic dystrophy RSD followed by symptoms of myelitis. Spinal cord MRI revealed cervical LETM extending to the brainstem. In spite of serological negativity, treatment of suspected neuromyelitis optica spectrum disorder NMOSD was initiated and resulted in symptom relief. Meanwhile, sudden death occurred and autonomic dysreflexia was the main culprit.

CONCLUSIONS

This case suggests that RSD could be the mere primary presentation of LETM, discusses the differential diagnoses of LETM in elderly patients, and suggests the possible risk of autonomic dysreflexia in such patients.

The Prevalence of Anti-Aquaporin 4 Antibody in Patients with Idiopathic Inflammatory Demyelinating Diseases Presented to a Tertiary Hospital in Malaysia: Presentation and Prognosis

Background. There have been inconsistent reports on the prevalence and pathogenicity of anti-Aquaporin 4 (AQP4) in patients presented with idiopathic inflammatory demyelinating diseases (IIDDs). Objective. To estimate the prevalence of anti-AQP4 antibody in patients with IIDDs presented to University Malaya Medical Centre in terms of patients' clinical and radiological presentations and prognoses. Methods. Retrospective data review of IIDDs patients presented from 2005 to 2015. Patients were classified into classical multiple sclerosis (CMS), opticospinal (OS) presentation, optic neuritis (ON), transverse myelitis (TM), brainstem syndrome (BS), and tumefactive MS. Anti-Aquaporin 4 antibody was tested using the Indirect Immunofluorescence Test (IIFT) cell-based assay. Statistical analysis was done using the SPSS version 20. Results. Anti-AQP4 antibody was detected in 53% of patients presented with IIDDs. CMS was more common in the seronegative group, 27/47 (57.45%; p < 0.001). Conversely, OS involvement was more common in the seropositive group, 26/53 (49.06%; p < 0.001). Longitudinally extensive spinal cord lesions (LESCLs) on MRI were also more common in the seropositive group, 29/40 (72.50%; p = 0.004). Only 2/40 (5.00%) had MRI evidence of patchy or multiple short-segment spinal cord lesions in the AQP4-positive group (p = 0.003). The relapse rate and Expanded Disability Status Scale (EDSS) were also higher in the seropositive group (5.43 versus 3.17, p = 0.005; 4.07 versus 2.51, p = 0.006, resp.). Typical clinical presentations that defined NMO were also seen in the seronegative patients, but in a lower frequency. Conclusion. Our cohort of patients had a higher prevalence of seropositivity of anti-AQP4 antibody as compared to those in Western countries. This was also associated with a more typical presentation of opticospinal involvement with LESCLs on MRI, a higher rate of relapse, and EDSS.

MOG antibody-positive, benign, unilateral, cerebral cortical encephalitis with epilepsy

Objective:

To describe the features of adult patients with benign, unilateral cerebral cortical encephalitis positive for the myelin oligodendrocyte glycoprotein (MOG) antibody.

Methods:

In this retrospective, cross-sectional study, after we encountered an index case of MOG antibody–positive unilateral cortical encephalitis with epileptic seizure, we tested for MOG antibody using our in-house, cell-based assay in a cohort of 24 consecutive adult patients with steroid-responsive encephalitis of unknown etiology seen at Tohoku University Hospital (2008–2014). We then analyzed the findings in MOG antibody–positive cases.

Results:

Three more patients, as well as the index case, were MOG antibody–positive, and all were adult men (median age 37 years, range 23–39 years). The main symptom was generalized epileptic seizure with or without abnormal behavior or consciousness disturbance. Two patients also developed unilateral benign optic neuritis (before or after seizure). In all patients, brain MRI demonstrated unilateral cerebral cortical fluid-attenuated inversion recovery hyperintense lesions, which were swollen and corresponded to hyperperfusion on SPECT. CSF studies showed moderate mononuclear pleocytosis with some polymorphonuclear cells and mildly elevated total protein levels, but myelin basic protein was not elevated. A screening of encephalitis-associated autoantibodies, including aquaporin-4, glutamate receptor, and voltage-gated potassium channel antibodies, was negative. All patients received antiepilepsy drugs and fully recovered after high-dose methylprednisolone, and the unilateral cortical MRI lesions subsequently disappeared. No patient experienced relapse.

Conclusions:

These MOG antibody–positive cases represent unique benign unilateral cortical encephalitis with epileptic seizure. The pathology may be autoimmune, although the findings differ from MOG antibody–associated demyelination and Rasmussen and other known immune-mediated encephalitides.

Predictors of response to first-line immunosuppressive therapy in neuromyelitis optica spectrum disorders

Background:

Azathioprine (AZA) and mycophenolate mofetil (MMF) are the most commonly used first-line therapies for patients with neuromyelitis optica spectrum disorders (NMOSD). However, some patients experience a relapse following AZA or MMF treatment.

Objectives:

To identify factors that predict a response to AZA or MMF in NMOSD.

Methods:

We retrospectively evaluated medical records from 116 patients who were initially treated with AZA or MMF for at least 6 months. Poor response was defined as ⩾2 relapses or ⩾1 severe relapse.

Results:

Among the 116 patients, 40 (34%) were classified as poor responders. Logistic regression analyses revealed that a poor response was independently associated with a pre-treatment history of a severe attack ( p < 0.001) and a younger age at disease onset ( p = 0.022). Among the 40 patients with a poor response, 29 (73%) switched to rituximab, and only 3 (10%) had a poor response to rituximab.

Conclusion:

Patients with a pre-treatment history of a severe attack and a younger age of onset exhibited an increased risk of a poor response to AZA or MMF therapy. Identifying patients who are unlikely to respond to AZA or MMF therapy may allow for treatment with more potent therapies that improve treatment outcomes.

Screening for onconeural antibodies in neuromyelitis optica spectrum disorders

Background

Some so-called “non-classical” paraneoplastic neurological syndromes (PNS), namely optic neuritis and myelitis, clinically overlap with neuromyelitis optica spectrum disorders (NMOSD), and conversely, in cancer-associated NMOSD, a paraneoplastic etiology has been suggested in rare cases. Therefore, we retrospectively investigated the prevalence of onconeural antibodies, which are highly predictive for a paraneoplastic etiology, and the prevalence of malignancies in NMOSD patients.

Methods

We retrospectively screened 23 consecutive patients from our clinic with NMOSD (13 were anti-aquaporin-4 [AQP4] antibody positive, 10 were AQP4 negative) for onconeural antibodies using an immunoblot.

Results

All patients were negative for a broad spectrum of antibodies targeting intracellular onconeural antigens (Hu, Yo, Ri, CV2/CRMP5, Ma1, Ma2, Zic4, SOX1, Tr, and amphiphysin). Notably, only two patients had a malignancy. However, neoplastic entities (astrocytic brain tumor and acute myeloid leukemia) were not typical for PNS.

Conclusions

Our data suggest that there is no need to routinely screen anti-AQP4 antibody positive NMOSD patients with a typical presentation for onconeural antibodies. Furthermore, absence of these antibodies in NMOSD, which is typically non-paraneoplastic, confirms their high specificity for PNS.

Short segment myelitis as a first manifestation of neuromyelitis optica spectrum disorders

BACKGROUND

Some patients with neuromyelitis optica spectrum disorders (NMOSD) present with spinal cord lesions extending fewer than three vertebral segments (short transverse myelitis, STM), hindering an early diagnosis.

OBJECTIVE

We investigated the frequency and imaging characteristics of STM lesions in patients presenting with myelitis as an initial manifestation of NMOSD.

METHODS

Patients seen at three referral hospitals in Korea between June 2005 and March 2015 who met the following inclusion criteria were recruited for review: seropositivity for aquaporin-4 antibody, initial presentation with myelitis and spinal cord magnetic resonance imaging (MRI) performed within 1 month of initial myelitis onset.

RESULTS

Of the 76 enrolled patients, 65 (85.5%) collectively had 69 longitudinally extensive transverse myelitis lesions, while the remaining 11 (14.5%) had a total of 15 STM lesions. Of the 15 STM lesions, 5 spanned 2.5 vertebral segments, 6 were continuous over two segments, 3 showed a length of 1.5 segments and 1 was confined to a single segment. On axial imaging, all of the STM lesions involved the central grey matter.

CONCLUSION

These MRI findings suggested that STM does not preclude the possibility of an NMOSD diagnosis.

Clinical characteristics of late-onset neuromyelitis optica spectrum disorder: A multicenter retrospective study in Korea

Background:

There are currently few studies regarding late-onset neuromyelitis optica spectrum disorder (LO-NMOSD).

Objective:

We aimed to describe the characteristic features of patients with LO-NMOSD in Korea.

Methods:

Anti-aquaporin-4 antibody-positive patients with neuromyelitis optica spectrum disorder (NMOSD) from nine tertiary hospitals were reviewed retrospectively. The patients were divided into two groups based on age of onset: LO-NMOSD (⩾50 years of age at onset) versus early-onset neuromyelitis optica spectrum disorder (EO-NMOSD) (<50 years of age at onset). Clinical, laboratory, and magnetic resonance imaging (MRI) parameters were investigated.

Results:

Among a total of 147 patients (125 female; age of onset, 39.4 ± 15.2 years), 45 patients (30.6%) had an age of onset of more than 50 years. Compared to patients with EO-NMOSD, patients with LO-NMOSD had more frequent isolated spinal cord involvement at onset (64.4% vs 37.2%, p = 0.002), less frequent involvement of the optic nerve (40.0% vs 67.7%, p = 0.002), and less frequent brain MRI lesions (31.1% vs 50.0%, p = 0.034). Furthermore, there was a significant positive correlation between age of onset and Expanded Disability Status Scale (EDSS) score at last follow-up ( r = 0.246, p = 0.003).

Conclusion:

Age of onset could be an important predictor of lesion location and clinical course of patients with NMOSD.

Anti Myelin Oligodendrocyte Glycoprotein associated Immunoglobulin G (AntiMOG-IgG)-associated Neuromyelitis Optica Spectrum Disorder with Persistent Disease Activity and Residual Cognitive Impairment

Antibodies targeting myelin oligodendrocyte glycoprotein (MOG) have been recently reported in association with idiopathic inflammatory central nervous system disorders. Initially believed to be a benign disorder, anti MOG-IgG was noted to cause steroid responsive recurrent optic neuritis and isolated longitudinally extensive myelitis. However, there is growing evidence that the disease may be predominantly relapsing, often producing severe visual loss and involving regions other than the spinal cord and optic nerve. We report an adolescent male with an aggressive disease course previously undescribed in anti MOG-IgG-associated disease that left him with residual cognitive dysfunction.