AQP4 and myeloid sarcoma: Future studies are needed to further confirm the role of the AQP1-Abs as biomarkers and pathogens in NMOSD, to characterize in depth the clinical phenotype of the AQP1-NMOSD subtype, and to determine the effect of the known therapies for AQP4-NMOSD cases, versus those for MS, in AQP1-NMOSD cases.