Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune demyelinating disorder of the optic nerves and the spinal cord that is linked to the presence of anti-aquaporin (AQP4) autoantibodies. Satralizumab, a humanized anti-IL-6 receptor (IL-6R) antibody, has been approved for the treatment of NMOSD but the effects of IL-6R inhibition in myelitis severity have not been fully explored.