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Is Asian type MS an MS phenotype, an NMO spectrum disorder, or a MOG-IgG related disease?
Regina Maria Papais Alvarenga1, Ana Carolina Ribeiro de Araújo E Araújo1, Anna Christiany Brandão Nascimento2
1Serviço de Neurologia, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, Brazil; Hospital Federal da Lagoa, Rio de Janeiro, Brazil.
Background:
A specific particularity of neurological diseases in Asia is the relative commonality of neuromyelitis optica (NMO) and Asian type MS (OSMS). Both conditions also occur in South American patients. The Brazilian population differs from the European and the Asian populations due to the mixture of ancestralities between European colonizers and African slaves. To better know the clinical characteristics of Brazilian patients with Asian type MS this study aimed to analyze the clinical, radiological and serological data that would help to distinguish between OSMS and NMO and clarify, in a Non-Asian population, if OSMS is an MS phenotype, an NMO spectrum disorder by 2015 classification, or a complement activating antibody to myelin oligodendrocyte glycoprotein (MOG-IgG) antibody-related disease.
Methods:
We selected cases retrospectively with NMO and OSMS in the medical registry of patients with idiopathic inflammatory demyelinating diseases under follow-up since 1997 in Federal Hospital da Lagoa, the principal reference center for MS treatment in Rio de Janeiro, Brazil. OSMS has selective involvement of the optic nerve and spinal cord with no cerebral or cerebellar symptoms associated with small spinal cord lesions and negativity for the aquaporin-4 antibody (AQP4-IgG). NMO full-filled the revised criteria (2006) associated with longitudinally extensive transverse myelitis (LETM). We recorded the following data: ethnicity/skin color, neurologic impairment "at nadir" and "at recovery" of the index events (optic neuritis and transverse myelitis), long term disability, mortality, health quality of life scores by the SF-36 questionnaire, CSF IgG oligoclonal bands and serological AQP4-IgG and MOG-IgG antibodies tested by Cell-based assay. The last brain MRIs were classified as either satisfying or not satisfying MAGNIMS radiologic criteria for MS or typical or not typical for NMOSD. The new classification of NMO spectrum disorders (2015) was applied.
Results:
Forty-one OSMS and 122 NMO cases were analyzed. OSMS affected mainly young white women, causing unilateral optic neuritis and partial myelitis with excellent recovery. After a mean disease duration of 20 years, 90% of the patients had free ambulation, and 70% had a mild disability or no disability. Only 7.2% presented a secondary progressive course, and no deaths occurred. All cases had negativity to AQP4-IgG and MOG-IgG biomarkers. 95% had resonance criteria for MS. OSMS differed from NMO by ethnicity, morbidity, and mortality: most were African descendants, with severe motor and visual dysfunction, and one third died. Only NMO cases full-filled the new NMOSD classification (52 AQP4-IgG positive, 29 AQP4-IgG negative, and 41 AQP4-IgG unknown).
Conclusion:
In Brazilian patients, OSMS and NMO are different immune-mediated diseases. OSMS is a milder MS phenotype.
Insights
Asian type Multiple Sclerosis (OSMS) in Brazil is a distinct, milder phenotype of MS, differing significantly from Neuromyelitis Optica (NMO) in clinical presentation, ethnicity, and outcomes.
Area of Science:
- Neuroimmunology
- Neurology
- Demyelinating Diseases
Background:
- Neuromyelitis Optica (NMO) and Asian type MS (OSMS) are common in Asia and also seen in South America.
- The Brazilian population's mixed ancestry may influence neurological disease presentation.
- Distinguishing OSMS from NMO in non-Asian populations is crucial for accurate diagnosis and treatment.
Purpose of the Study:
- To analyze clinical, radiological, and serological data of Brazilian patients with OSMS.
- To differentiate OSMS from NMO in a non-Asian population.
- To determine if OSMS is an MS phenotype, an NMO spectrum disorder, or MOG-IgG related disease.
Main Methods:
- Retrospective analysis of patients with NMO and OSMS from 1997 onwards.
- OSMS defined by optic nerve/spinal cord involvement, negative AQP4-IgG, and no cerebral symptoms.
- NMO defined by revised 2006 criteria and longitudinally extensive transverse myelitis (LETM).
- Data collected included demographics, clinical outcomes, quality of life, CSF analysis, and serological testing for AQP4-IgG and MOG-IgG.
Main Results:
- OSMS predominantly affected young white women, presenting with unilateral optic neuritis and partial myelitis with excellent recovery.
- After 20 years, 90% of OSMS patients retained ambulation, with mild or no disability and no deaths.
- OSMS cases were negative for AQP4-IgG and MOG-IgG, with 95% meeting MS MRI criteria.
- NMO cases, often in African descendants, showed severe dysfunction and higher mortality, fulfilling NMOSD criteria.
Conclusions:
- In Brazil, OSMS and NMO represent distinct immune-mediated diseases.
- OSMS is characterized as a milder phenotype of Multiple Sclerosis (MS).
- The findings support classifying OSMS as MS rather than an NMO spectrum disorder in this population.
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