Neuromyelitis optica in Austria in 2011: to bridge the gap between neuroepidemiological research and practice in a study population of 8.4 million people

Sex ratio and age of onset in AQP4 antibody-associated NMOSD: a review and meta-analysis

BACKGROUND

Aquaporin-4 (AQP4) antibody-associated neuromyelitis optica spectrum disorder (NMOSD) is an antibody-mediated inflammatory disease of the central nervous system. We have undertaken a systematic review and meta-analysis to ascertain the sex ratio and mean age of onset for AQP4 antibody associated NMOSD. We have also explored factors that impact on these demographic data.

METHODS

A systematic search of databases was conducted according to the PRISMA guidelines. Articles reporting sex distribution and age of onset for AQP4 antibody-associated NMSOD were reviewed. An initially inclusive approach involving exploration with regression meta-analysis was followed by an analysis of just AQP4 antibody positive cases.

RESULTS

A total of 528 articles were screened to yield 89 articles covering 19,415 individuals from 88 population samples. The female:male sex ratio was significantly influenced by the proportion of AQP4 antibody positive cases in the samples studied (p < 0.001). For AQP4 antibody-positive cases the overall estimate of the sex ratio was 8.89 (95% CI 7.78-10.15). For paediatric populations the estimate was 5.68 (95% CI 4.01-8.03) and for late-onset cases, it was 5.48 (95% CI 4.10-7.33). The mean age of onset was significantly associated with the mean life expectancy of the population sampled (p < 0.001). The mean age of onset for AQP4 antibody-positive cases in long-lived populations was 41.7 years versus 33.3 years in the remainder.

CONCLUSIONS

The female:male sex ratio and the mean age of onset of AQP4 antibody-associated NMOSD are significantly higher than MS. The sex ratio increases with the proportion of cases that are positive for AQP4 antibodies and the mean age of onset increases with population life expectancy.

Clinical features and prognosis of Tibetan patients with neuromyelitis optica spectrum disorder are different from those of Han Chinese patients

We compared the prognosis of Tibetan and Han Chinese patients with neuromyelitis optica spectrum disorder (NMOSD). The Expanded Disability Status Scale (EDSS) score at each attack, response to immunosuppressive therapy, risk of first relapse, severe attack, visual disability, motor disability, and total risk of disability were compared between Tibetan and Han Chinese patients. Tibetan patients showed higher EDSS during acute attacks. Annualized relapse rate did not differ between groups. Risk of severe attack, visual disability, and total risk of disability were higher in Tibetan patients. Tibetan patients with NMOSD have a higher risk of poor prognosis than Han Chinese patients.

Patterns of neuromyelitis optica spectrum disorder attacks in different age groups and sexes depending on the status of immunosuppressive therapy: A retrospective cohort study

BACKGROUND AND PURPOSE

The association between onset age and sex with relapse risk in neuromyelitis optica spectrum disorder (NMOSD) remains inconclusive. We aimed to describe the clinical features of patients with NMOSD in different age groups and sexes and to analyse relapse characteristics pre- and post-immunosuppressive therapy (IST).

METHODS

Patients with NMOSD were retrospectively reviewed from our clinical centre's database. Demographic and clinical data, attack presentation, and disease course pre- and post-IST were investigated. We also analysed the effect of onset age on the annualized relapse rate and relapse risk according to sex and IST status. Interactions on the additive scale between onset age and sex were analysed. A restricted cubic spline was used to analyse potential nonlinear correlations. Longitudinal changes in the Expanded Disability Status Scale score across NMOSD attacks were analysed using linear mixed-effect models.

RESULTS

In total, 533 patients experienced 1394 attacks pre-IST and 753 relapses post-IST. Older age at onset was correlated with more myelitis attacks but fewer optic neuritis attacks, with no sex-related differences in attack presentation. Pre-IST, relapse risk increased with age at onset in women, while a U-shaped correlation between onset age and relapse risk was found in men. Post-IST, an inverted U-shaped association between the predicted relapse risk and onset age was observed in women. Conversely, a negative correlation between the predicted relapse risk and onset age was found in men. Overall, a higher ratio of myelitis attacks was found post-IST.

CONCLUSIONS

Patients of different onset ages and sexes had different relapse patterns before and after IST.

Treatment of neuromyelitis optica spectrum disorder: revisiting the complement system and other aspects of pathogenesis

Neuromyelitis optica spectrum disorder (NMOSD) represents a rare neuroimmunological disease causing recurrent attacks and accumulation of permanent disability in affected patients. The discovery of the pathogenic IgG‑1 antibody targeting a water channel expressed in astrocytes, aquaporin 4, constitutes a milestone achievement. Subsequently, multiple pathophysiological aspects of this distinct disease entity have been investigated. Demyelinating lesions and axonal damage ensue from autoantibodies targeting an astroglial epitope. This conundrum has been addressed in the current disease model, where activation of the complement system as well as B cells and interleukin 6 (IL-6) emerged as key contributors. It is the aim of this review to address these factors in light of novel treatment compounds which reflect these pathophysiological concepts in aiming for attack prevention, thus reducing disease burden in patients with NMOSD.

Worldwide prevalence of neuromyelitis optica spectrum disorder (NMOSD) and neuromyelitis optica (NMO): a systematic review and meta-analysis

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a progressive demyelinating disease of the central nervous system that has overlapping symptoms with multiple sclerosis (MS) but differs from it in a variety of ways. Previous studies have reported conflicting results trying to estimate the number of individuals affected by them which is why we designed this systematic review and meta-analysis to estimate the worldwide prevalence and incidence of NMOSD/NMO based on current evidence.

METHODS

We searched PubMed, Scopus, EMBASE, Web of Science, and gray literature including references from the identified studies, review studies, and conference abstracts which were published up to February 1, 2022. We used all MeSH terms pertaining to "NMOSD," "NMO," and all the terms on "prevalence," "incidence," and "epidemiology" to identify the search components. Pooled effect sizes were measured using random-effect model by DerSimonian-Laird.

RESULTS

The prevalence and incidence rates of NMOSD/NMO ranged from 0.07 to 10 and 0.029 to 0.880 per 100,000 population, respectively. The overall pooled prevalence of NMO per 100,000 population was 1.54 (I²: 98.4%, 95% CI: 1.13-1.96, P< 0.001) based on the 2006 criteria, 1.51 (I²: 99.4%, 95% CI: 1.21-1.81, P < 0.001) based on the 2015 criteria and 2.16 (I²: 89.4%, 95% CI: 1.46-2.86, P < 0.001) based on the 2006/2015 criteria. The overall annual incidence of NMO per 100,000 population was 0.155 (I²: 95%, 95% CI: 0.115-0.195, P < 0.001) based on the 2006 criteria and 0.278 (I²: 100%, 95% CI: 0.135-0.420, P < 0.001) based on the 2015 criteria. The prevalence rates were highest in French West Indies and South Korea, and lowest in Cuba and Australia, based on the 2006 and 2015 criteria, respectively. Also, the highest annual incidence rates were obtained for Sweden and Slovak republic and the lowest for Cuba and Australia based on the 2006 and 2015 criteria, respectively. All estimated rates were higher among females compared to males.

CONCLUSION

Although rare, NMOSD/NMO impact affected individuals in devastating ways. Several large-scale prospective studies are required to reach a comprehension of the epidemiological aspects of these notorious demyelinating conditions.

Late-onset Neuromyelitis Optica Spectrum Disorder with Anti-AQP4 and Anti-MOG Antibodies

OBJECTIVE

This study aimed to evaluate the clinical characteristics and prognosis of late-onset (≥ 50 years) neuromyelitis optica spectrum disorder (LO-NMOSD), and compare them with those of early-onset (< 50 years) NMOSD (EO-NMOSD) and NMOSD with various antibody serostatuses.

METHODS

From January 2015 to December 2020, 360 anti-aquaporin-4 antibody (AQP4-ab)-positive and 130 anti-myelin oligodendrocyte glycoprotein antibody (MOG-ab)-positive patients presented to the Huashan Hospital, China. We retrospectively reviewed their medical records, including the Expanded Disability Status Scale (EDSS) score at each visit and the annualized relapse rate (ARR). Prognostic outcomes included the time to first relapse, blindness, motor dysfunction, severe motor dysfunction, and death. Correlations between the age at onset, lesion location, and clinical parameters were analyzed.

RESULTS

This study included 122 (24.9%) patients with LO-NMOSD, 101 with AQP4-ab and 21 with MOG-ab. Compared with EO-NMOSD patients, those with LO-NMOSD had higher EDSS scores, more frequent disease onset with transverse myelitis, blindness, motor dysfunction, and severe motor dysfunction. Compared with LO-NMOSD patients with MOG-ab, those with AQP4-ab had a worse prognosis. Age at disease onset had a significantly positive correlation with EDSS score at the last follow-up of all NMOSD patients, but a negative correlation with ARR-1 (ARR excluding the first attack, calculated from disease onset to final follow-up) in NMOSD patients with AQP4-ab.

CONCLUSIONS

Patients with LO-NMOSD, especially those with AQP4-ab, had a worse prognosis compared with patients with EO-NMOSD. Age at disease onset and antibody serostatus predicted blindness and motor dysfunction.

Clinical risk factors and prognostic model for idiopathic inflammatory demyelinating diseases after haploidentical hematopoietic stem cell transplantation in patients with hematological malignancies

Idiopathic inflammatory demyelinating diseases (IIDDs) of the central nervous system (CNS) are rare but serious neurological complications of haploidentical hematopoietic stem cell transplantation (haplo-HSCT). However, the risk factors and a method to predict the prognosis of post-transplantation CNS IIDDs are not available. This retrospective study first reviewed data from 4532 patients who received haplo-HSCT during 2008-2019 in our center, and 184 patients (4.1%) with IIDDs after haplo-HSCT were identified. Grades II to IV acute graft-versus-host disease (aGVHD) (p < 0.001) and chronic GVHD (cGVHD) (p = 0.009) were identified as risk factors for developing IIDDs after haplo-HSCT. We then divided the 184 IIDD patients into a derivation cohort and validation cohort due to transplantation time to develop and validate a model for predicting the prognosis of IIDDs. In the multivariate analysis of the derivation cohort, four candidate predictors were entered into the final prognostic model: cytomegalovirus (CMV) infection, Epstein-Barr virus (EBV) infection, IgG synthesis (IgG-syn) and spinal cord lesions. The prognostic model had an area under the receiver operating characteristic curve of 0.864 (95% CI: 0.803-0.925) in the internal validation cohort and 0.871 (95% CI: 0.806-0.931) in the external validation cohort. The calibration plots showed a high agreement between the predicted and observed outcomes. Decision curve analysis indicated that IIDD patients could benefit from the clinical application of the prognostic model. The identification of IIDD patients after allo-HSCT who have a poor prognosis might allow timely treatment and improve patient survival and outcomes.

[Epidemiology of neuromyelitis optica spectrum disorder]

Neuromyelitis optica spectrum disorder (NMOSD) is a group of rare and mostly severe autoimmune demyelinating central nervous system disorders which prevalence is 0.7-1 per 100.000 population and incidence is 0.037-0.73 per 100.000 person-years. NMOSD may present as a combination of uni- or bilateral optic neuritis, transverse myelitis or lesions of brain stem and other brain regions. The symptoms are mostly relapsing (up to 97.5%) and progressive. Occurrence of relapses is associated with seropositivity for aquaporin-4 (up to 80% of NMOSD patients) and bears a less favorable prognosis (mortality up to 32%). Women seropositive for aquaporin 4 constitute 90% of NMOSD patients. Compared to other demyelinating disorders, NMOSD is characterized by late onset (mean age is about 39 years) and association with other autoimmune disorders, including systemic lupus erythematosus, myasthenia gravis and Sjogren's syndrome. A genetic predisposition was found among Blacks and Asians, with HLA-DRB1*03:01 gene associated with higher risk of NMOSD in Asians. The course of the disease tends to be more severe in Blacks. There are clusters of an increased incidence of NMOSD in the Carribeans and in the Far East. Continued increase of prevalence and incidence of NMOSD worldwide compels continued epidemiological research in order to provide early diagnosis and treatment for this disorder.

Comparisons of clinical phenotype, radiological and laboratory features, and therapy of neuromyelitis optica spectrum disorder by regions: update and challenges

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system (CNS) associated with autoantibody (ab) to aquaporin-4 (AQP4). There is obvious variation between regions and countries in the epidemiology, clinical features and management in NMOSD. Based on published population-based observation and cohort studies, the different clinical pattern of NMOSD has been seen in several geographical regions and some of these patients with NMOSD-like features do not fully meet the current diagnostic criteria, which is needed to consider the value of recently revised diagnostic criteria. At present, all treatments applied in NMOSD have made great progress, however, these treatments failed in AQP4 ab negative and refractory patients. Therefore, it is necessary to turn into an innovative idea and to open a new era of NMOSD treatment to develop novel and diverse targets and effective therapeutic drugs in NMOSD and to conduct the trails in large clinical samples and case-control studies to confirm their therapeutic effects on NMOSD in the future, which still remain a challenge.

Incidence and prevalence of neuromyelitis optica spectrum disorders in Slovakia

OBJECTIVE

: Neuromyelitis optica spectrum disorders (NMOSDs) are a group of rare, inflammatory, demyelinating diseases that affect the central nervous system. Neither the incidence nor the prevalence of NMOSD has been determined in Slovakia thus far. The aim of this study was to determine both the incidence and the prevalence of NMOSD in Slovakia using the 2015 International Panel of NMOSD diagnosis (IPND) criteria.

METHODS

: We performed a population-based study in Slovakia to estimate both the incidence and the prevalence of NMOSD during the period from 1 January 2006 through 31 December 2019. NMOSD cases were reported from multiple sources and the diagnosis was subsequently verified using the IPND criteria by a joint commitee of three neurologists. The prevalence is reported as number of cases per 100,000 inhabitans and the incidence as number of new cases per 1,000,000 person-years. Age-adjusted rates to the WHO standard population 2005-2025 were also calculated.

RESULTS

: We identified 63 NMOSD cases. The crude point-prevalence rate was 1.37 (95% CI 1.03-1.71) per 100,000 inhabitants. The crude indidence rate was 0.88 (95% CI 0.65-1.12) per 1,000,000 person-years. The age-adjusted point-prevalence rate was 1.42 (95% CI 1.07-1.84) per 100,000 persons and the age-adjusted incidence rate was 0.96 (95% CI 0.72-1.25) per 1,000,000 person-years.

CONCLUSION

: The NMOSD epidemiological situation in Slovakia is comparable to those reported from other Caucasian populations.

Population-based head-to-head comparison of the clinical characteristics and epidemiology of AQP4 antibody-positive NMOSD between two European countries

BACKGROUND

Population-based clinical studies in neuromyelitis optica spectrum disorder (NMOSD) and epidemiological and clinical comparisons of White ethnicities are missing. In a large population-based international cohort, we extensively characterized aquaporin-4 antibody seropositive (AQP4-Ab+) NMOSD, and also compared the clinical, radiological and epidemiological features between two European populations residing in different areas.

METHODS

Between self-reported Danish and Hungarian ethnicities, we compared the population-based clinical features, disability outcomes, and death of 134 AQP4-Ab+ NMOSD cases fulfilling the 2015 International Panel for NMO Diagnosis (IPND) criteria. For precise comparison of epidemiology, we conducted a population-based head-to-head comparative study of the age-standardized prevalence (January 1, 2014) and incidence (2007-2013) of AQP4-Ab+ NMO/NMOSD among adults (≥16 years) in Denmark (4.6 million) and Hungary (6.4 million) by applying 2015 IPND (NMOSD) criteria and 2006 Wingerchuk (NMO).

RESULTS

Danes were more likely to present with transverse myelitis and were more affected by spinal cord damage on long-term disability. Hungarians presented most often with optic neuritis, although visual outcome was similar in the groups. No differences were observed in sex, disease course, relapse rate, autoimmune comorbidity, mortality, brain MRI, and treatment strategies. The age-standardized prevalence estimates of AQP4-Ab+ NMOSD (2015 IPND criteria) in Denmark vs. Hungary were 0.66 vs. 1.43 (/100,000) while incidence rates were 0.04 vs. 0.11 (/100,000 person-years); similar differences were found based on the 2006 NMO criteria.

CONCLUSIONS

This head-to-head comparative study indicates different disease characteristics and epidemiology among White populations in Europe, and substantiates the need for population-based genetic and environmental studies in NMOSD.

Early Treatment Initiation With Oral Prednisolone for Relapse Prevention Alleviates Depression and Fatigue in Aquaporin-4-Positive Neuromyelitis optica Spectrum Disorder

Background:Neuromyelitis optica spectrum disorder (NMOSD) is a relapsing autoimmune-related neurological disorder of the central nervous system. Most patients with NMOSD have serum anti-aquaporin-4 immunoglobulin G antibodies (AQP4-IgG). In addition to optic neuritis and myelitis, other insidious symptoms such as depressive state and chronic fatigue in NMOSD are gradually being recognized.

Methods: To elucidate the impact of low- to medium-dose oral prednisolone (PSL) as a relapse prevention therapy for psychiatric disturbances and chronic fatigue in NMOSD, we evaluated clinical data from 39 patients with AQP4-IgG-positive NMOSD, along with the details of present and cumulative oral PSL dosage.

Results: Thirty-six of the 39 patients were treated with low- to medium-dose oral PSL, and the mean and standard deviation of the present daily dose of oral PSL were 7.9 ± 4.0 mg/day. None of the patients were treated with a daily PSL dose of >15 mg. As a result, the disease duration and the untreated period before starting oral PSL showed weak to moderate correlations with the subsequent severities of psychiatric disturbance and fatigue level. Meanwhile, none of the other treatment-related variables evaluated, such as the present oral PSL daily dose, cumulative PSL dose, months of oral PSL administration, previous courses of steroid pulse therapy, and coadministered immunosuppressants, were correlated with these insidious symptoms.

Conclusion: Our results suggest that the use of long-term low- to medium-dose oral PSL ≤15 mg daily for relapse prevention in AQP4-IgG-positive NMOSD would not aggravate the psychiatric and fatigue conditions. On the contrary, early initiation of oral PSL for relapse prevention, together with significantly decreased relapse rate, alleviated the subsequent depressive state and fatigue from the disease.

Prevalence of neuromyelitis optica spectrum disorder in Belo Horizonte, Southeast Brazil

BACKGROUND

Studies on the prevalence of neuromyelitis optica spectrum disorder (NMOSD) are still scarce. The aim of the current study was to determine the prevalence rate of NMOSD in Belo Horizonte, southeast Brazil, where the prevalence rate of multiple sclerosis (MS) has already been established.

METHODS

For this observational study, eligible patients had to meet the 2015 International Panel for Neuromyelitis Optica Diagnosis, be seen at the study center between January 2000 and February 2019 and live in Belo Horizonte. The prevalence rate of NMOSD was estimated based on the number of MS and NMOSD patients seen at same Center during the same period, and the previously established prevalence of MS in Belo Horizonte.

RESULTS

During the study period, there were 69 patients with NMOSD, 60 (87.0%) of whom were females, and 44 (63.8%) non-whites. The median age at disease onset was 36.7 (4-72) years, the mean EDSS score 4.78±2.36, and the mean ARR 0.57±0.43. Anti-aquaporin-4 immunoglobulin testing was available for 61 (88.4%) patients, of whom 41 (67.2%) had a positive result. During the same period, 280 MS patients were seen. Considering the local known prevalence rate of MS of 18.1/100,000 inhabitants, the estimated NMOSD prevalence rate in Belo Horizonte was 4.52/100,000 (95% CI 3.72-5.43) inhabitants.

CONCLUSION

The prevalence rate of NMOSD in Belo Horizonte is high as compared with those found in most of the studies reported to date.

Clinical Characteristics of Chinese Male Patients with Aquaporin-4 Antibody-Positive Late-Onset Neuromyelitis Optica Spectrum Disorder

BACKGROUND AND OBJECTIVE

Limited studies are available for male patients with anti-aquaporin-4 antibody (AQP4-Ab)-positive late-onset neuromyelitis optica spectrum disease (LONMOSD). The aim of this study was to investigate the clinical characteristics of Chinese male patients with AQP4-Ab-positive LONMOSD.

METHODS

We retrospectively reviewed the medical records of 12 male patients with LONMOSD, 16 male patients with early-onset NMOSD (EONMOSD), and 64 female patients with LONMOSD. These enrolled patients were classified according to the age of onset: LONMOSD (≥50 years of age at onset) versus EONMOSD (<50 years of age at onset). Clinical characteristics and magnetic resonance imaging (MRI) findings were collected. All included patients were positive for AQP4 antibody.

RESULTS

Compared with female LONMOSD patients, male LONMOSD patients had less frequent transverse myelitis (TM) at onset (8.33 vs. 53.13%, p = 0.004) and lower Expanded Disability Status Scale (EDSS) scores (median 1 vs. 4, p = 0.036). Compared with male EONMOSD patients, male LONMOSD patients had a shorter time from onset to diagnosis (0.85 months vs. 6.00 months, p = 0.04).

CONCLUSION

Less common TM at onset, less disease severity, and shorter time from onset to diagnosis probably occur in male LONMOSD patients.

Worldwide Incidence and Prevalence of Neuromyelitis Optica: A Systematic Review

Objective

Since the last epidemiologic review of neuromyelitis optica/neuromyelitis optica spectrum disorder (NMO/NMOSD), 22 additional studies have been conducted. We systematically review the worldwide prevalence, incidence, and basic demographic characteristics of NMOSD and provide a critical overview of studies.

Methods

PubMed, Ovid MEDLINE, and Embase using Medical Subject Headings and keyword search terms and reference lists of retrieved articles were searched from 1999 until August 2019. We collected data on the country; region; methods of case assessment and aquaporin-4 antibody (AQP4-Ab) test; study period; limitations; incidence (per 100,000 person-years); prevalence (per 100,000 persons); and age-, sex-, and ethnic group–specific incidence or prevalence.

Results

We identified 33 relevant articles. The results indicated the highest estimates of incidence and prevalence of NMOSD in Afro-Caribbean region (0.73/100 000 person-years [95% CI: 0.45–1.01] and 10/100 000 persons [95% CI: 6.8–13.2]). The lowest incidence and prevalence of NMOSD were found in Australia and New Zealand (0.037/100 000 person-years [95% CI: 0.036–0.038] and 0.7/100,000 persons [95% CI: 0.66–0.74]). There was prominent female predominance in adults and the AQP4-Ab–seropositive subpopulation. The incidence and prevalence peaked in middle-aged adults. African ethnicity had the highest incidence and prevalence of NMOSD, whereas White ethnicity had the lowest. No remarkable trend of incidence was described over time.

Conclusion

NMOSD is a rare disease worldwide. Variations in prevalence and incidence have been described among different geographic areas and ethnicities. These are only partially explained by different study methods and NMO/NMOSD definitions, highlighting the need for specifically designed epidemiologic studies to identify genetic effects and etiologic factors.

Clinical and Radiological Characteristics of Neuromyelitis Optica Spectrum Disorder: The Experience from Saudi Arabia

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune astrocytopathy that affects several regions of the central nervous system (CNS) with a predilection for the optic nerves and spinal cord. Epidemiological studies of NMOSD are uncommon in the Middle East and up-to-date, there are no such data from Saudi Arabia. In this study, we aim to study the clinical pattern of NMOSD patients in Saudi Arabia.

METHODS

A retrospective multi-center observational study was conducted at King Abdulaziz Medical City in Jeddah and Riyadh, Saudi Arabia. The inclusion criteria consisted of all the patients with either neuromyelitis optica according to the 2006 criteria or NMOSD according to the 2015 criteria. The study period was 20 years.

RESULTS

A total of 23 patients were included in the study. Four were males (17.4%) and 19 were females (82.6%). The attack type was optic neuritis in 3 patients (13.0%), transverse myelitis in 15 patients (65.2%), and both in 5 patients (21.7%). All patients (100%) received pulse steroid therapy (intravenous methylprednisolone 1 g for 5 days) at the onset of the disease. Fifteen patients had plasma exchange therapy (65.2%). All patients received maintenance immunosuppressive treatment except 1 (4.3%).

CONCLUSION

NMOSD is a rare, broad-spectrum, polyphasic, rare disorder primarily affecting the optic pathway and the spinal cord either in isolation or simultaneously. Unfortunately, there are no adequate studies that assess NMOSD cohorts in Saudi Arabia despite the increased number of diagnosed cases. In addition, there is no registry for this disorder with only a few specialized centers dealing with its management. It is time to establish specialized demyelinating disease centers and build expertise in both common and rare diseases in this category.

Neuromyelitis optica spectrum disorders

The disease concept of Neuromyelitis Optica Spectrum Disorders(NMOSD) has undergone a significant change over the last two decades including the detection of Myelin Oligodendrocyte Glycoprotein(MOG) antibody in patients who are seronegative for aquaporin-4 antibody. Aquaporin-4 antibody positive NMOSD is now regarded as an immune astrocytopathy. Conversely, MOG antibody associated disease is known to target myelin rather than astrocytes, leading to an NMOSD syndrome with distinct clinical and radiological features. Incorporation of clinical features like area postrema syndrome, brainstem syndrome, diencephalic syndrome and cortical manifestations as core clinical characteristics into the revised diagnostic criteria has widened the clinical spectrum of NMOSD. With the development of these criteria, it is possible to make the diagnosis at an earlier stage so that effective immunosuppression can be instituted promptly for a better long-term prognosis. Newer therapeutic agents have been introduced for aquaporin-4 seropositive NMOSD disease; however, challenges remain in treating seronegative disease because of limited treatment options.

Neuromyelitis optica

Neuromyelitis optica (NMO; also known as Devic syndrome) is a clinical syndrome characterized by attacks of acute optic neuritis and transverse myelitis. In most patients, NMO is caused by pathogenetic serum IgG autoantibodies to aquaporin 4 (AQP4), the most abundant water-channel protein in the central nervous system. In a subset of patients negative for AQP4-IgG, pathogenetic serum IgG antibodies to myelin oligodendrocyte glycoprotein, an antigen in the outer myelin sheath of central nervous system neurons, are present. Other causes of NMO (such as paraneoplastic disorders and neurosarcoidosis) are rare. NMO was previously associated with a poor prognosis; however, treatment with steroids and plasma exchange for acute attacks and with immunosuppressants (in particular, B cell-depleting agents) for attack prevention has greatly improved the long-term outcomes. Recently, a number of randomized controlled trials have been completed and the first drugs, all therapeutic monoclonal antibodies, have been approved for the treatment of AQP4-IgG-positive NMO and its formes frustes.

Safety and efficacy of plasma exchange for the treatment of optic neuritis in neuromyelitis optica spectrum disorders: A protocol for systematic review and meta-analysis

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) is an inflammatory and heterogeneous astrocyte disorder of the central nervous system (CNS), concerned because of its high pathogenicity, high risk of recurrence, and poor prognosis. Optic neuritis (ON) is the first manifestation in 30% to 50% of NMOSD patients, and eventually involved optic nerve in 70% of patients. The idiopathic ON associated with NMO is called NMO-associated ON(NMO-ON). There are substantial costs to the countries and individuals associated with treatment of NMO-ON. Intravenous corticosteroids (IVCSs), as the first-line therapy, leads to unsatisfactory outcomes for NMO-ON and is associated with potential adverse events (AEs). Emerging evidences have proved the important value and potential prospect of plasma exchange (PLEX) in NMO-ON. Although PLEX is increasingly used in NMO-ON, its therapeutic effect and safety are still controversial. There are no systematic reviews yet that evaluated the effects of PLEX against other therapies in patients with NMO-NO. It is therefore timely to perform a systematic review to assess the efficacy and safety of PLEX on current research for its potential use in clinical practice in treating NMO-ON.

METHODS

The systematic review will include all of the randomized controlled trials (RCT) on the efficacy and safety of PLEX for NMO-ON. A relevant literature search by sensitive search strategies was conducted using the following electronic databases from their inception to November 30, 2019: PubMed, Web of Science, EMBASE, the Cochrane Library, China National Knowledge Infrastructure (CNKI), Wanfang Database, China Science and Technology Journal database (VIP) and CBM. We will also search registers of clinical trials, potential gray literature, and conference abstracts. There are no limits on language and publication status. The literature screening, data extraction, and quality assessment will be conducted by 2 reviewers independently. The reporting quality and risk of bias will be assessed by other 2 researchers. Best-corrected visual acuity (BCVA), annualized relapse rate (ARR), the frequency and extent of adverse events (AEs) will be evaluated as the primary outcome. The secondary outcomes will include expanded disability status scales (EDSS), relapse-free rate, peri-papillary retinal nerve fibers layer (pRNFL) or macular volume, visual electrophysiology examinations, standard automated perimetry examinations, time to the next attack. Meta-analysis will be performed using RevMan5.3 software provided by the Cochrane Collaboration and Stata 12.0.

RESULTS

This study will provide a comprehensive review based on current evidence of PLEX treatment for NMO-ON in several aspects, including BCVA, ARR, the frequency and extent of adverse events (AEs), EDSS, relapse-free rate, etc. CONCLUSION:: The conclusion of this study will provide evidence to determine whether PLEX is an effective and safe intervention for patients with NMO-ON.

ETHICS AND DISSEMINATION

It is not necessary to obtain ethical approval for this study, given that this protocol is for a systematic review. The systematic review will be published in a peer-reviewed journal, presented at conferences and will be shared on social media platforms.

PROSPERO REGISTRATION NUMBER

PROSPERO CRD 42020162585.

Epidemiology of Neuromyelitis Optica Spectrum Disorder and Its Prevalence and Incidence Worldwide

Neuromyelitis optica spectrum disorder (NMOSD) is an uncommon inflammatory disease of the central nervous system, manifesting clinically as optic neuritis, myelitis, and certain brain and brainstem syndromes. Cases clinically diagnosed as NMOSD may include aquaporin 4 (AQP4)-antibody-seropositive autoimmune astrocytopathic disease, myelin oligodendrocyte glycoprotein (MOG)-antibody-seropositive inflammatory demyelinating disease, and double-seronegative disease. AQP4-antibody disease has a high female-to-male ratio (up to 9:1), and its mean age at onset of ~40 years is later than that seen in multiple sclerosis. For MOG-antibody disease, its gender ratio is closer to 1:1, and it is more common in children than in adults. Its clinical phenotypes differ but overlap with those of AQP4-antibody disease and include acute disseminated encephalomyelitis, brainstem and cerebral cortical encephalitis, as well as optic neuritis and myelitis. Double-seronegative disease requires further research and clarification. Population-based studies over the past two decades report the prevalence and incidence of NMOSD in different populations worldwide. One relevant finding is the varying prevalence observed in different racial groups. Consistently, the prevalence of NMOSD among Whites is ~1/100,000 population, with an annual incidence of <1/million population. Among East Asians, the prevalence is higher, at ~3.5/100,000 population, while the prevalence in Blacks may be up to 10/100,000 population. For MOG-antibody disease, hospital-based studies largely do not observe any significant racial preponderance so far. This disorder comprises a significant proportion of NMOSD cases that are AQP4-antibody-seronegative. A recent Dutch nationwide study reported the annual incidence of MOG-antibody disease as 1.6/million population (adult: 1.3/million, children: 3.1/million). Clinical and radiological differences between AQP4-antibody and MOG-antibody associated diseases have led to interest in the revisions of NMOSD definition and expanded stratification based on detection of a specific autoantibody biomarker. More population-based studies in different geographical regions and racial groups will be useful to further inform the prevalence and incidence of NMOSD and their antibody-specific subgroups. Accessibility to AQP4-antibody and MOG-antibody testing, which is limited in many centers, is a challenge to overcome. Environmental and genetic studies will be useful accompaniments to identify other potential pathogenetic factors and specific biomarkers in NMOSD.

Clinical and radiological profile of neuromyelitis optica spectrum disorders in an Ecuadorian cohort

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is a complex disease characterized by a severe inflammation of the central nervous system (CNS). This disease typically manifests with recurrent optic neuritis (ON) and acute transverse myelitis (ATM). The clinical and radiological spectrum of NMOSD is little known in Latin America (LATAM) and few reports have been published in the literature so far. In Ecuador, no reports on NMOSD have been published. For this reason we aimed to assess the demographic, clinical and imaging characteristics of patients with NMOSD from third level hospitals from Ecuador.

METHODS

This is a descriptive study in which we assessed medical reports of patients with inflammatory demyelinating diseases who were attended in third level hospitals from Ecuador in 2017. Then we applied the 2015 diagnostic criteria, those patients who met the new NMOSD diagnostic criteria were selected and analyzed. Additionally, exploratory sub-analyses were subsequently carried out.

RESULTS

We identified 59 patients with NMOSD, the relative frequency of NMOSD was 15.9%. The multiple sclerosis (MS) /NMOSD ratio was 5.2:1. Twenty four percent of patients were newly defined as having NMOSD when 2015 criteria was applied. The median time to diagnoses was shorter by the 2015 criteria than 2006 criteria (p<0.001). NMOSD was more prevalent in women (female/male ratio 4.4:1). The disease onset was more frequent at the fourth decade of life. The most common symptoms at the disease onset were ON and the association of ON with ATM. The mean of expanded disability status scale (EDSS) was 4.8 (SD±1.8). Concomitant autoimmune diseases were infrequent in this population (11.9%). The brain magnetic resonance imaging (MRI) abnormalities were present in 25.7% of patients at disease onset. Spinal cord MRI showed longitudinally extensive transverse myelitis (LETM) in 91.5% of cases. Recurrent NMOSD was frequent in this cohort (88%). Positivity for antibodies against aquaporin-4 (AQP4-IgG) which was measured through indirect immunofluorescence assay (IIF) was identified in 81% of the patients tested. Patients with seronegative AQP4-IgG had higher grade of disability than seropositive patients (p<0.05). Ninety eight percent of patients received treatment with immunosuppressive drugs. Three patients died due to gastric cancer (1 patient) and infectious diseases (2 patients).

CONCLUSIONS

This is the first descriptive study in an Ecuadorian cohort of patients with NMOSD. We show a wide epidemiological, clinical and radiological spectrum of NMOSD.

Neuromyelitis optica: a pilot study of clinical presentation and status of serological biomarker AQP4 among patients admitted to a tertiary centre in NCNS, Sudan

Background

Neuromyelitis optica (NMO) is a demyelinating disease primarily affecting the optic nerves and spinal cord. It is distinguished from other demyelinating conditions by the presence of AQP4-IgG and serum aquaporin 4 (AQP4), found mainly in the blood–brain barrier. This descriptive study was conducted from January 2015 to June 2018 at the National Center for Neurological Sciences (NCNS) in Khartoum, Sudan. All participants were Sudanese patients diagnosed with NMO. In our study the selection of cases was based on Dean Wingerchuk diagnostic criteria (2006), which states that the diagnosis of NMO should meet two absolute criteria and two supportive criteria. The absolute criteria are myelitis and optic neuritis, whereas supportive criteria include radiological findings obtained from brain and spinal cord MRI. Furthermore, AQP4-IgG levels were measured from cerebrospinal fluid (CSF) and serum using immunofluorescence. Data were collected by a pre-designed questionnaire and analyzed using SPSS version 17. A p value < 0.05 was considered statistically significant.

Results

A total of 31 patients were enrolled in this study [6 male (19.4%) and 25 female (80.6%)]. The mean age was 38 ± 12.8 years. Motor and visual difficulties were the initial symptoms and occurred in 21 (67.7%) and 10 (32.3%) patients, respectively. Fundoscopy confirmed optic atrophy in 22 (71.0%) patients. The course of the disease revealed one relapse in 21 patients (67.7%). Seropositive AQP4-IgG were seen in 23 patients (79.31%). There was a significant correlation between AQP4 and response to treatment (p ≤ 0.038). The correlation between serum AQP4-IgG, showed that, complete improvement was detected in 2 patients (6.9%) one of them was positive and the other was negative, 20 (69.0%) patients presented with some disability, among them 18 (62.1%) were positive and 2 (6.9%) were negative, while 7 patients showed no improvement (24.1%) 4 out of them were positive (13.8%) and 3 were negative (10.3%).

Conclusion

At the initial presentation of NMO, longitudinal myelitis was observed more frequently than optic neuritis. More than two third of the patients showed strong seropositivity for serum AQP4. Most seropositive patients showed a good response to treatment but with residual disabilities.

Neuromyelitis optica spectrum disorders in the Arabian Gulf: challenges and growing experience

Neuromyelitis optica spectrum disorders (NMOSD) have been studied in different ethnic groups, including Asians, African-Americans, and Caucasians. Demonstrating the clinical features among diverse communities is important to understand the variable disease phenotypes, which will lead to further classification and better clinical management. Testing for antibody against aquaporin-4 (AQP4), the most common target antigen in NMOSD, is not available in many countries and tests use different methods, with variable sensitivity. With negative antibody results, the diagnosis of NMOSD becomes challenging and may affect the outcomes of patients with NMOSD. There are no adequate studies that assess NMOSD cohorts in the Arabian Gulf region, despite the increasing number of diagnosed cases. It is worth assessing NMOSD cohorts in the Arabian Gulf population to study the natural history of disease and to establish an epidemiological background for future perspectives. Various challenges to implement such a mission are outlined, including disease rarity, overlapping presenting symptoms and signs, which posed the issue of mimickers in the differential diagnosis, lack of specialized clinics, absence of highly sensitive testing methods for diagnosis, and the indefinite agreement on the negative AQP4 NMOSD criteria. Collaborative efforts started to take a place among many experts in the region to establish a registry of NMOSD patients for better perception of the disease pattern.

Two Cases of Very-Late-Onset Neuromyelitis Optica Spectrum Disorder (NMOSD) in Patients over the Age of 80

We report two cases of very-late-onset neuromyelitis optica spectrum disorder (NMOSD) in patients over the age of 80 with transverse myelopathy as the initial manifestation. In both cases, the patients presented with paraplegia and sensory, bladder, and rectal disturbances. Thoracic magnetic resonance imaging showed longitudinal high-intensity signals on a T2-weighted image. The patients received high-dose methylprednisolone. Their serum was positive for anti-AQP4 antibody (cell-based assay) during the clinical course. They were diagnosed with NMOSD and treated with immunoadsorption, plasmapheresis, and followed up with daily prednisolone. Very-late-onset NMOSD in patients over the age of 80 has only rarely been reported. The present cases suggest that NMOSD should be considered for elderly patients presenting with transverse myelitis. Early diagnosis and treatment are important.

Neuromyelitis optica spectrum disorders in Arabian Gulf (NMOAG); establishment and initial characterization of a patient registry

OBJECTIVE

To describe the clinical and radiological characteristics of neuromyelitis optica spectrum disorders (NMOSD) patients from the Arabian Gulf relative to anti-aquaporin 4 antibody serostatus.

METHODS

Retrospective multicentre study of hospital records of patients diagnosed with NMOSD based on 2015 International Panel on NMOSD Diagnosis (IPND) consensus criteria.

RESULTS

One hundred forty four patients were evaluated, 64.3% were anti-AQP4 antibody positive. Mean age at onset and disease duration were 31±12 and 7 ± 6 years respectively. Patients were predominantly female (4.7:1). Overall; relapsing course (80%) was more common than monophasic (20%). Optic neuritis was the most frequent presentation (48.6%), regardless of serostatus. The proportion of patients (54.3%) with visual acuity of ≤ 0.1 was higher in the seropositive group (p = 0.018). Primary presenting symptoms of transverse myelitis (TM) were observed in 29% of patients, and were the most significant correlate of hospitalization (p<0.001). Relative to anti-APQ4 serostatus, there were no significant differences in terms of age of onset, course, relapse rates or efficacy outcomes except for oligoclonal bands (OCB), which were more often present in seronegative patients (40% vs.22.5%; p = 0.054). Irrespective of serostatus, several disease modifying therapies were instituted including steroids or immunosuppressives, mostly, rituximab and azathioprine in the cohort irrespective of serostatus. The use of rituximab resulted in reduction in disease activity.

CONCLUSION

This is the first descriptive NMOSD cohort in the Arabian Gulf region. Seropositive patients were more prevalent with female predominance. Relapsing course was more common than monophasic. However, anti-AQP4 serostatus did not impact disease duration, relapse rate or therapeutic effectiveness. These findings offer new insights into natural history of NMOSD in patients of the Arabian Gulf and allow comparison with patient populations in different World regions.

Neuromyelitis Optica Spectrum Disorder and Anti-MOG Syndromes

Neuromyelitis optica spectrum disorder (NMOSD) and anti-myelin oligodendrocyte glycoprotein (anti-MOG) syndromes are immune-mediated inflammatory conditions of the central nervous system that frequently involve the optic nerves and the spinal cord. Because of their similar clinical manifestations and habitual relapsing course they are frequently confounded with multiple sclerosis (MS). Early and accurate diagnosis of these distinct conditions is relevant as they have different treatments. Some agents used for MS treatment may be deleterious to NMOSD. NMOSD is frequently associated with antibodies which target aquaporin-4 (AQP4), the most abundant water channel in the CNS, located in the astrocytic processes at the blood-brain barrier (BBB). On the other hand, anti-MOG syndromes result from damage to myelin oligodendrocyte glycoprotein (MOG), expressed on surfaces of oligodendrocytes and myelin sheaths. Acute transverse myelitis with longitudinally extensive lesion on spinal MRI is the most frequent inaugural manifestation of NMOSD, usually followed by optic neuritis. Other core clinical characteristics include area postrema syndrome, brainstem, diencephalic and cerebral symptoms that may be associated with typical MRI abnormalities. Acute disseminated encephalomyelitis and bilateral or recurrent optic neuritis are the most frequent anti-MOG syndromes in children and adults, respectively. Attacks are usually treated with steroids, and relapses prevention with immunosuppressive drugs. Promising emerging therapies for NMOSD include monoclonal antibodies and tolerization.

Epidemiology of NMOSD in Sweden from 1987 to 2013: A nationwide population-based study

Objective

To report the yearly incidence rate and prevalence of neuromyelitis spectrum disorder (NMOSD) in Sweden and to investigate clinical characteristics, treatment, and outcome.

Methods

We conducted a retrospective study of hospital case records of 294 individuals diagnosed with neuromyelitis optica (NMO) (G36.0 ICD-10, 341.0 ICD-9) in the Swedish National Patient Register from 1987 to end of 2013 or detected by the presence of aquaporin-4 (AQP4) immunoglobulin G (IgG) in serum during the study period. Ninety-two patients (51 NMO and 41 NMOSD) met the 2006 Wingerchuk criteria and were included in the study. Ten patients with an onset of NMO prior to 1987 and alive at the end of 2013 were included when estimating the prevalence.

Results

The average yearly incidence rate per 1,000,000 individuals increased significantly from 0.30 (confidence interval [CI] 0.19–0.41) between 1987 and 2006 to 0.79 (CI 0.55–1.03) between 2007 and 2013. The prevalence was 10.4 (CI 8.5–12.6) per 1,000,000 individuals at end of 2013. The median time from onset to first relapse was 1.42 years (range 0.58–3.90). The probability of relapse was 60% and 75% after 5 and 10 years after onset. More than 80% were treated with immunosuppressive drugs. Three patients died during the study period.

Conclusion

The increased incidence rate during the study period was likely due to heightened awareness and increased access to MRI and AQP4-IgG analysis. Incidence and prevalence of NMO in Sweden correspond to other countries with a predominately Caucasian population. We found that most patients were treated with immunosuppressant drugs, presumably resulting in low mortality among the detected cases.

The Cerebrospinal Fluid in Multiple Sclerosis

Investigation of cerebrospinal fluid (CSF) in the diagnostic work-up in suspected multiple sclerosis (MS) patients has regained attention in the latest version of the diagnostic criteria due to its good diagnostic accuracy and increasing issues with misdiagnosis of MS based on over interpretation of neuroimaging results. The hallmark of MS-specific changes in CSF is the detection of oligoclonal bands (OCB) which occur in the vast majority of MS patients. Lack of OCB has a very high negative predictive value indicating a red flag during the diagnostic work-up, and alternative diagnoses should be considered in such patients. Additional molecules of CSF can help to support the diagnosis of MS, improve the differential diagnosis of MS subtypes and predict the course of the disease, thus selecting the optimal therapy for each patient.

Clinical and radiological characteristics of neuromyelitis optica spectrum disorder in the North Egyptian Nile Delta

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disorder of the central nervous system that was previously thought to be a subtype of multiple sclerosis (MS). Epidemiology studies of NMOSD are rare in both Middle East and North African countries. To our knowledge, there are no such studies in Egypt. Herein, we describe a case series of NMOSD patients from North Egyptian Nile Delta region and compare them to NMOSD in other parts in the Middle East and the world.

METHODS

This is a case series study of NMOSD patients who were seen at the neuroimmunology clinic, Elhadara Hospital, University of Alexandria, Egypt, from January 2017 to January 2018. We describe their clinical, serological and radiological features.

RESULTS

Our study identified twenty Egyptian patients, all of who fulfilled the 2015 international NMOSD diagnostic criteria. Ten tested positive for AQP4 antibodies in the serum while the other ten were seronegative. The mean age at onset was 27.8 years with an average disease duration of 6.8 years. There was a strong female predominance with a ratio of 5.6:1. We identified clinical features of the cohort that differ from those reported in other worldwide studies.

INTERPRETATION

This is the first NMOSD case series in Egypt. Despite some limitation in testing and access to care, there are features of our NMOSD cases that appear to be different from other worldwide cohorts reported in the literature.

Nationwide prevalence and incidence study of neuromyelitis optica spectrum disorder in Denmark

Objectives

To estimate the nationwide population-based incidence, prevalence, and geographical distribution of neuromyelitis optica (NMO) spectrum disorder (NMOSD) in Denmark based on the 2015 International Panel for NMO Diagnosis (IPND) criteria.

Methods

We conducted a multicentre, historically prospective study. Data were sourced from the Danish National Patient Registry, the Danish Multiple Sclerosis Registry, departments of neurology, and laboratories providing aquaporin-4 antibody test. Cases were selected based on the 2006 Wingerchuk and the 2015 IPND criteria and were individually validated by an expert panel.

Results

We confirmed NMO in 30 cases (2006 criteria) and NMOSD in 56 cases (2015 IPND criteria) between 2007 and 2014. Defined by the 2006 criteria, the incidence of NMO was 0.029 per 100,000 person-years (95% confidence interval [CI] 0.014–0.051), and the prevalence (aged 16 years and older) was 0.566 per 100,000 (95% CI 0.370–0.830). Based on the 2015 IPND criteria, the incidence of NMOSD was 0.070 per 100,000 person-years (95% CI 0.046–0.102), and the prevalence (aged 16 years and older) was 1.09 per 100,000 (95% CI 0.808–1.440), without regional differences.

Conclusions

Our estimates of incidence and prevalence are similar to other Caucasian population–based studies using the 2015 IPND criteria. We found no geographical clustering in Denmark.

Diagnosis and Treatment of NMO Spectrum Disorder and MOG-Encephalomyelitis

Neuromyelitis optica spectrum disorders (NMOSD) are autoantibody mediated chronic inflammatory diseases. Serum antibodies (Abs) against the aquaporin-4 water channel lead to recurrent attacks of optic neuritis, myelitis and/or brainstem syndromes. In some patients with symptoms of NMOSD, no AQP4-Abs but Abs against myelin-oligodendrocyte-glycoprotein (MOG) are detectable. These clinical syndromes are now frequently referred to as "MOG-encephalomyelitis" (MOG-EM). Here we give an overview on current recommendations concerning diagnosis of NMOSD and MOG-EM. These include antibody and further laboratory testing, MR imaging and optical coherence tomography. We discuss therapeutic options of acute attacks as well as longterm immunosuppressive treatment, including azathioprine, rituximab, and immunoglobulins.

A nationwide epidemiological study on the prevalence of multiple sclerosis and neuromyelitis optica spectrum disorder with important multi-ethnic differences in Malaysia

OBJECTIVES

This study looked at observed crude prevalence/incidence of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) in Malaysia and identified any inter-ethnic differences for MS/NMOSD.

METHODS

This was a nationwide tertiary hospital-based retrospective cross-sectional study using the capture-recapture method. It looked at the estimated crude prevalence of confirmed MS and NMOSD and annual incidence on 29 December 2017. Recapture of data was done between February and March 2018 on 1 March 2018. Public and referring private institutions were accessed.

RESULTS

The survey identified 767 MS and 545 NMOSD subjects, with crude prevalence rates of 2.73 per 100,000 (95% confidence interval (CI): 2.53; 2.92 per 100,000 population) and 1.94 per 100,000 (95% CI: 1.77; 2.10 per 100,000 population) with observed crude annual incidence of 0.55 (95% CI: 0.43; 0.58) for MS and 0.39 per 100,000 (95% CI: 0.35; 0.47) for NMOSD. The MS:NMOSD ratios were 1.4:1.0. The capture-recapture method revealed 913 MS (95% CI: 910; 915.9) and 580 (95% CI: 578.8; 581.2) NMOSD with prevalence per 100,000 of 3.26 (95% CI: 3.05; 3.47) and 2.07 (95% CI: 1.90; 2.24), respectively. In the MS group, 59.4% were Malay, 16.6% Chinese, 20.5% Indian, and 3.5% were from indigenous groups. In the NMOSD group, 47.3% were Malay, 46.9% Chinese, 3.5% Indian, and 2.3% were from other indigenous groups. The ratio of NMOSD to MS among the Chinese was 2:1, but the ratio of MS to NMOSD among the Malays was 1.8:1, and that in Indians was 8.3:1.

CONCLUSION

There is a modest increase in the prevalence of MS and NMOSD in Malaysia with inter-ethnic differences for MS/NMOSD.

Central nervous system neuroinflammatory disorders in Asian/Pacific regions

PURPOSE OF REVIEW

The discovery of aquaporin-4 (AQP4) antibodies with high specificity for neuromyelitis optica spectrum disorder (NMOSD) has induced tremendous changes in the approach and management of central nervous system (CNS) neuroinflammatory disorders. Owing to the increasing availability of the AQP4 antibody assay and evolution of diagnostic criteria for multiple sclerosis and NMOSD, recent studies have reevaluated CNS neuroinflammatory disorders. This review describes recent advances in the understanding of CNS neuroinflammatory disorders in Asian/Pacific regions.

RECENT FINDINGS

Although multiple sclerosis prevalence is lower in Asian countries than in Western countries, the overall clinical features of multiple sclerosis are comparable between these countries. Hospital-based studies have reported that the frequency of NMOSD is higher in Asian populations (22-42%) than in white populations (2-26%). Despite improvements in the AQP4 antibody assay, AQP4 antibodies are not detected in certain patients with NMOSD. Recently, myelin oligodendrocyte glycoprotein (MOG) antibodies have been identified in AQP4 antibody-negative patients with the NMOSD phenotype, and the clinical features differ slightly between MOG antibody-positive patients and AQP4 antibody-positive patients.

SUMMARY

The understanding of CNS neuroinflammatory disorders in Asian/Pacific regions continues to evolve owing to the discovery of new biological markers and recognition of broader clinical phenotypes.

Neuromyelitis Optica (Devic's Syndrome): an Appraisal

Neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD), previously known as Devic's syndrome, are a group of inflammatory disorders of the central nervous system (CNS) characterized by severe, immune-mediated demyelination and axonal damage, predominantly targeting optic nerves and the spinal cord typically associated with a disease-specific serum NMO-IgG antibody that selectively binds aquaporin-4 (AQP4). The classic and best-defined features of NMOSD include acute attacks of bilateral or rapidly sequential optic neuritis (leading to visual loss) or transverse myelitis (often causing limb weakness and bladder dysfunction) or both with a typically relapsing course. The diagnosis of NMO/NMOSD requires a consistent history and examination with typical clinical presentations, findings on spinal cord neuroimaging with MRI, cerebrospinal fluid analysis along with determination of AQP4-IgG serum autoantibody status, and exclusion of other disorders. Two major advances in this field has been the development of diagnostic criteria and treatment recommendations. Consensus diagnostic criteria have been established and were recently revised and published in 2015, enhancing the ability to make a diagnosis and appropriately evaluate these disorders. Expert recommendations and uncontrolled trials form the basis of treatment guidelines. All patients with suspected NMOSD should be treated for acute attacks as soon as possible with high-dose intravenous methylprednisolone -1 gram daily for three to five consecutive days and in some cases, plasma exchange should be used. It is recommended that every patient with NMOSD be started on an immunosuppressive agent, such as, azathioprine, methotrexate, or mycophenolate and in some cases, rituximab, soon after the acute attack and usually be treated for about 5 years after the attack. These advances have helped improve the prognosis and outcome in these disorders.

Prevalence of neuromyelitis optica spectrum disorder in the multi-ethnic Penang Island, Malaysia, and a review of worldwide prevalence

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) occurs worldwide in all ethnicities. Recently, population-based studies have shown that NMOSD is more common among non-White populations. There is scarce data about NMOSD prevalence in South East Asian populations.

METHODS

(1) A population-based study was undertaken to estimate NMOSD prevalence in the multi-ethnic Penang Island, Malaysia, comprising Chinese, Malays, and Indians. Medical records of NMOSD patients followed up at the Penang General Hospital (the neurology referral centre in Penang Island) were reviewed. The 2015 diagnostic criteria of the International Panel for NMO Diagnosis were used for case ascertainment. (2) A review of population-based prevalence studies of NMOSD worldwide was carried out. PubMed and conference proceedings were searched for such studies.

RESULTS

Of the 28 NMOSD patients, 14 were residents of Penang Island on prevalence day [13 (93%) Chinese and one (7%) Malay]. All 14 patients were females and aquaporin 4 seropositive. The prevalence of NMOSD in Penang Island was 1.99/100,000 population; according to ethnicities, the prevalence in Chinese was significantly higher than in Malays (3.31/100,000 vs 0.43/100,000, respectively, p = 0.0195).

CONCLUSION

Based on our and other population-based studies, among Asians, East Asian origin populations (Chinese and Japanese) appear to have higher NMOSD prevalence than other Asian ethnic groups. Worldwide, Blacks seem to have the highest NMOSD prevalence. More studies in different geographical regions and ethnic groups will be useful to further inform about potential factors in NMOSD pathogenesis.

Cervical cord myelin water imaging shows degenerative changes over one year in multiple sclerosis but not neuromyelitis optica spectrum disorder

Spinal cord pathology is a feature of both neuromyelitis optica spectrum disorder (NMOSD) and relapsing-remitting multiple sclerosis (MS). While subclinical disease activity has been described in MS using quantitative magnetic resonance imaging measures, current evidence suggests that neurodegeneration is absent between relapses in NMOSD, although most evidence comes from brain studies. We aimed to assess cross-sectional differences and longitudinal changes in myelin integrity in relapse-free MS and NMOSD subjects over one year. 15 NMOSD, 15 MS subjects, and 17 healthy controls were scanned at 3 T using a cervical cord mcDESPOT protocol. A subset of 8 NMOSD, 11 MS subjects and 14 controls completed follow-up. Measures of the myelin water fraction (f_M) within lesioned and non-lesioned cord segments were collected. At baseline, f_M in lesioned and non-lesioned segments was significantly reduced in MS (lesioned: p = 0.002; non-lesioned: p = 0.03) and NMOSD (lesioned: p = 0.0007; non-lesioned: p = 0.002) compared to controls. Longitudinally, f_M decreased within non-lesioned cord segments in the MS group (− 7.3%, p = 0.02), but not in NMOSD (+ 5.8%, p = 0.1), while change in lesioned segments f_M did not differ from controls' in either patient group. These results suggest that degenerative changes outside of lesioned areas can be observed over a short time frame in MS, but not NMOSD, and support the use of longitudinal myelin water imaging for the assessment of pathological changes in the cervical cord in demyelinating diseases.

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MS and NMOSD subjects underwent longitudinal cervical cord myelin water imaging.

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Reduced myelin water fraction in MS and NMOSD normal-appearing and lesioned areas

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Decrease in myelin in normal-appearing tissue over 1 year in MS, but not NMOSD

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Further evidence that disease progression is absent between relapses in NMOSD.

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.

Characterization of the binding pattern of human aquaporin-4 autoantibodies in patients with neuromyelitis optica spectrum disorders

BACKGROUND

The discovery of a highly specific antibody against the aquaporin-4 (AQP4) water channel (AQP4-IgG) unified the spectrum of neuromyelitis optica spectrum disorders (NMOSD), which are considered to be antibody-mediated autoimmune diseases. The AQP4 water channel is located on astrocytic end-feet processes and consists of six transmembrane helical domains forming three extracellular loops A, C, and E in which defined amino acids were already proven to be critical for AQP4-IgG binding. However, the clinical relevance of these findings is unclear. Therefore, we have characterized the epitope specificity of AQP4-IgG-positive NMOSD patients.

METHODS

We established a cell-based flow cytometry assay for the quantitative detection of AQP4-IgG-positive serum samples. Human embryonic kidney (HEK) cells were transiently transfected with an EmGFP-tagged AQP4-M23, AQP4-M1, or six AQP4-M23 extracellular loop mutants including two mutations in loop A (serial AA substitution, insertion of a myc-tag), two in loop C (N153Q, insertion of a myc-tag), and two in loop E (H230G, insertion of a myc-tag). Fourty-seven baseline and 49 follow-up serum samples and six paired cerebrospinal fluid (CSF) baseline samples of 47 AQP4-IgG-positive Austrian NMOSD patients were then tested for their binding capability to AQP4-M1 and AQP4-M23 isoforms and these six extracellular loop mutants.

RESULTS

Overall, we could identify two broad patterns of antibody recognition based on differential sensitivity to mutations in extracellular loop A. Pattern A was characterized by reduced binding to the two mutations in loop A, whereas pattern B had only partial or no reduced binding to these mutations. These two patterns were not associated with significant differences in demographic and clinical parameters or serum titers in this retrospective study. Interestingly, we found a change of AQP4-IgG epitope recognition pattern in seven of 20 NMOSD patients with available follow-up samples. Moreover, we found different binding patterns in five of six paired CSF versus serum samples, with a predominance of pattern A in CSF.

CONCLUSIONS

Our study demonstrates that AQP4-IgG in sera of NMOSD patients show distinct patterns of antibody recognition. The clinical and diagnostic relevance of these findings have to be addressed in prospective studies.

Incidence of AQP4-IgG seropositive neuromyelitis optica spectrum disorders in the Netherlands: About one in a million

Neuromyelitis optica (NMO) is a rare autoimmune disease affecting the optic nerves and spinal cord. In the majority of NMO patients anti-aquaporin-4 antibodies (AQP4-IgG) are detected. Here we assessed a nationwide incidence of AQP4-IgG-seropositive NMO spectrum disorders (NMOSD) in the Netherlands based on results of one central laboratory. Data were collected since the introduction of the highly sensitive cell-based assay for six consecutive years. Samples from 2795 individual patients have been received; of them 94 (3.4%) were seropositive. Based on the Dutch population with 16.6 million inhabitants, the mean incidence of AQP4-IgG-seropositive NMOSD was calculated at 0.09 per 100,000 people.

Central Nervous System Idiopathic Inflammatory Demyelinating Disorders in South Americans: A Descriptive, Multicenter, Cross-Sectional Study

The idiopathic inflammatory demyelinating disease (IIDD) spectrum has been investigated among different populations, and the results have indicated a low relative frequency of neuromyelitis optica (NMO) among multiple sclerosis (MS) cases in whites (1.2%-1.5%), increasing in Mestizos (8%) and Africans (15.4%-27.5%) living in areas of low MS prevalence. South America (SA) was colonized by Europeans from the Iberian Peninsula, and their miscegenation with natives and Africans slaves resulted in significant racial mixing. The current study analyzed the IIDD spectrum in SA after accounting for the ethnic heterogeneity of its population. A cross-sectional multicenter study was performed. Only individuals followed in 2011 with a confirmed diagnosis of IIDD using new diagnostic criteria were considered eligible. Patients’ demographic, clinical and laboratory data were collected. In all, 1,917 individuals from 22 MS centers were included (73.7% female, 63.0% white, 28.0% African, 7.0% Mestizo, and 0.2% Asian). The main disease categories and their associated frequencies were MS (76.9%), NMO (11.8%), other NMO syndromes (6.5%), CIS (3.5%), ADEM (1.0%), and acute encephalopathy (0.4%). Females predominated in all main categories. The white ethnicity also predominated, except in NMO. Except in ADEM, the disease onset occurred between 20 and 39 years old, early onset in 8.2% of all cases, and late onset occurred in 8.9%. The long-term morbidity after a mean disease time of 9.28±7.7 years was characterized by mild disability in all categories except in NMO, which was scored as moderate. Disease time among those with MS was positively correlated with the expanded disability status scale (EDSS) score (r=0.374; p=<0.001). This correlation was not observed in people with NMO or those with other NMO spectrum disorders (NMOSDs). Among patients with NMO, 83.2% showed a relapsing-remitting course, and 16.8% showed a monophasic course. The NMO-IgG antibody tested using indirect immunofluorescence (IIF) with a composite substrate of mouse tissues in 200 NMOSD cases was positive in people with NMO (95/162; 58.6%), longitudinally extensive transverse myelitis (10/30; 33.3%) and bilateral or recurrent optic neuritis (8/8; 100%). No association of NMO-IgG antibody positivity was found with gender, age at onset, ethnicity, early or late onset forms, disease course, or long-term severe disability. The relative frequency of NMO among relapsing-remitting MS (RRMS) + NMO cases in SA was 14.0%. Despite the high degree of miscegenation found in SA, MS affects three quarters of all patients with IIDD, mainly white young women who share similar clinical characteristics to those in Western populations in the northern hemisphere, with the exception of ethnicity; approximately one-third of all cases occur among non-white individuals. At the last assessment, the majority of RRMS patients showed mild disability, and the risk for secondary progression was significantly superior among those of African ethnicity. NMO comprises 11.8% of all IIDD cases in SA, affecting mostly young African-Brazilian women, evolving with a recurrent course and causing moderate or severe disability in both ethnic groups. The South-North gradient with increasing NMO and non-white individuals from Argentina, Paraguay, Brazil and Venezuela confirmed previous studies showing a higher frequency of NMO among non-white populations.

Very late-onset neuromyelitis optica spectrum disorder beyond the age of 75

Aquaporin-4 antibody (AQP4-Ab)-positive neuromyelitis optica spectrum disorder (NMOSD) is a rare but often severe autoimmune disease with median onset around 40 years of age. We report characteristics of three very-late-onset NMOSD (including complete NMO) patients >75 years of age, in whom this diagnosis initially seemed unlikely because of their age and age-associated concomitant diseases, and briefly review the literature. All three patients, aged 79, 82 and 88 years, presented with a spinal cord syndrome as the first clinical manifestation of AQP4-Ab-positive NMOSD. They all had severe relapses unless immunosuppressive therapy was initiated, and one untreated patient died of a fatal NMOSD course. Two patients developed side effects of immunosuppression. We conclude that a first manifestation of NMOSD should be considered even in patients beyond the age of 75 years with a compatible syndrome, especially longitudinally extensive myelitis. Early diagnosis and treatment are feasible and highly relevant. Special attention is warranted in the elderly to recognize adverse effects of immunosuppressive therapies as early as possible.