The intervals between attacks and lumbar punctures (days, mean±SD) were 18.4±14.0 in AQP4-Ab–positive NMOSD, 23.6±12.0 in seronegative NMOSD, 19.0±11.0 in MOG-Ab–positive NMOSD, and 24.3±8.4 in MS. The gene discussed is AQP4; the disease is myeloid sarcoma.