Advances in Neuromyelitis Optica Spectrum Disorders (NMOSD)

Neuromyelitis optica spectrum disorders (NMOSD) is an autoimmune demyelinating disease, more specifically an astrocytopathy, of the central nervous system (CNS). The majority of NMOSD patients are women, and recent observations have shown that the age of onset is younger and the CNS is more commonly affected in Asian and black patients than in white patients, in whom the age of onset is typically around 40 years. Thus, progress in understanding the pathogenesis and in developing diagnostic and therapeutic strategies is critical. Formerly known as Devic's disease or neuromyelitis optica (NMO), NMOSD is characterized by demyelination primarily of the optic nerves and spinal cord. The discovery of NMO IgG directed against aquaporin-4 (AQP4) is a milestone in establishing diagnostic criteria for NMOSD and distinguishing it from other neuroimmune diseases, particularly multiple sclerosis (MS). More recently, it has been shown that about 30% of individuals with the NMOSD phenotype but negative AQP4 antibody have antibodies to myelin oligodendrocyte glycoprotein (MOG) and have a disease called MOG associated disease (MOGAD), which can look like NMOSD and is a major cause of ADEM in children

However, in the absence of a classic animal model for NMOSD, such as Experimental Autoimmune Encephalomyelitis (EAE) in MS, much of the pathogenesis of NMOSD remains unclear. Previous attempts to establish an NMOSD model were based on NMO-IgG and experimental autoimmune encephalomyelitis (EAE), but these do not reveal the whole picture of the disease. The relationship between NMO-IgG and MOG -IgG in NMOSD has not been fully elucidated, and the diagnostic and prognostic value of autoimmune antibodies is limited because it is not clear whether titers are related to relapse risk or disease severity. Furthermore, it is difficult to draw a clear line between NMOSD and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), especially when autoimmune antibodies with low affinity or low serum levels are not detected by conventional laboratory techniques. Therefore, it is necessary to develop diagnostic or prognostic strategies, such as the development of highly sensitive cell-based assays that can be used in clinical practice, or the identification of new potential biomarkers, etc. These advances in the validity and prognostic value of biomarkers will also help in the development of diagnostic criteria for NMOSD and MOGAD. In addition, there is an ongoing need for refinement and development of treatments for both diseases, especially in seronegative NMOSD patients.

This Research Topic aims to discuss new discoveries in the field of NMOSD. We welcome submissions of Original Research, Brief Research Reports, Reviews, Mini-Reviews and Opinions in the following areas:

- Molecular mechanism(s) and signaling pathways involved in the pathogenesis of NMOSD.
- Animal models and underlying immunopathogenesis of NMOSD.
- Evolution of diagnostic criteria for NMOSD, especially with MOG antibodies, and diagnostic workup of NMOSD mimics such as Sjogren's syndrome, sarcoid, lymphoma, MOGAD, etc.
- Comparison of autoimmunity between NMOSD and other autoimmune diseases like MS, MOGAD, autoimmune encephalitis, Sjogren's syndrome and systemic lupus erythematosus (SLE).
- Advances in MOGAD such as clinical presentation, diagnostic criteria, prognosis, treatment and related controversies.
- Identification of new serum biomarkers and prognostic factors, including markers that may predict impending relapse
- Development of highly sensitive laboratory techniques to detect low-affinity autoimmune antibodies or serum levels in NMOSD or MOGAD
- Innovative therapeutic approaches for NMOSD