AQP4 and neuromyelitis optica: Autoimmune myelopathies are a heterogeneous group of immune-mediated spinal cord disorders encompassing myelopathies with an immune attack on the spinal cord (e.g., aquaporin-4-IgG seropositive neuromyelitis optica), myelopathies occurring with systemic autoimmune disorders, paraneoplastic autoimmune myelopathies, postinfectious autoimmune myelopathies, and myelopathies considered to be immune related (e.g., multiple sclerosis and sarcoidosis) (71).