Updates in NMOSD and MOGAD Diagnosis and Treatment A Tale of Two Central Nervous System Autoimmune Inflammatory Disorders

The recent identification of AQP4+NMOSD and MOGAD as separate disorders has prompted the development of separate diagnostic criteria for MOGAD diagnosis. The stratification of patients based on the presence/absence of AQP4-IgG in NMOSD and stratification by antibody-titer in MOGAD represents the main differences between the two criteria. Using CBA in serum, AQP4-IgG and MOG-IgG are sensitive and highly specific but caution is needed with low-positive MOG-IgG, which is found in 1% to 2% of disease controls. In addition, specific MRI features of the diseases are described and included as supportive criteria in uncertain cases. NMOSD negative for AQP4-IgG and MOG-IgG likely represents a heterogenous group of disorders that should be a focus of research to potentially discover new antibodies that associate with demyelination. A number of highly effective attack-prevention treatments are now available for AQP4+NMOSD and should be started promptly at diagnosis. Empiric attack-prevention treatments in MOGAD are generally reserved for those with 2 or more attacks. However, level 1 evidence is lacking in MOGAD. The approach to developing treatments in AQP4+NMOSD will be a useful template for MOGAD and randomized clinical trials are now underway with the hope for a proven attackprevention treatment in the near future.