The ratio of sGFAP/sNfL is especially promising for differentiating seropositive NMOSD from MOGAD and MS (15, 16, 20), with a sGFAP/sNfL quotient above 5.71 being 73% sensitive and 75.8% specific for AQP4-IgG-positive NMOSD compared to MS (15). This evidence concerns the gene AQP4 and myeloid sarcoma.