Neuromyelitis optica (NMO) is characterized by severe optic neuritis and transverse myelitis. The relationship of NMO to multiple sclerosis (MS) has long been debated. With the discovery of an NMO-specific autoantibody to aquaporin 4 (AQP4), the clinical, radiological, and laboratory findings have clarified the differences between NMO and MS, and NMO spectrum disorders (NMOSD) have been proposed as the unifying term for the entire clinical entity including brain syndromes. Pathological studies in NMO showed loss of immunoreactivity to AQP4 and glial fibrillary acidic protein, but a relative preservation of myelin basic protein, especially at the lesions with perivascular deposition of immunoglobulins and complements. AQP4 antibody-positive NMOSD is now considered an autoimmune astrocytopathic disease. In addition, the definite diagnosis should be made initially from the therapeutic viewpoint, because there have been several AQP4 antibody-positive NMOSD cases exacerbated by disease-modifying drugs for MS. In recent years, the antibody against myelin oligodendrocyte glycoprotein (MOG) has been studied for its association with other types of acute demyelinating diseases, such as acute or multiphasic disseminated encephalomyelitis, optic neuritis, NMOSD and brainstem or cerebral cortical encephalomyelitis. Recent brain biopsied MOG antibody-positive case reports have suggested the dominance of humoral immunity, but it is not well elucidated whether the cellular immune responses against MOG could develop perivenous inflammatory demyelination like classical acute disseminated encephalomyelitis pathology. In the present review, we focus on two distinct diseases, aquaporin 4 antibody-related NMOSD and MOG antibody-related diseases, both of which were recently differentiated from MS by means of the disease-specific autoantibodies and the distinct pathophysiologies.
- acute disseminated encephalomyelitis
- aquaporin 4 antibody
- multiple sclerosis
- myelin oligodendrocyte glycoprotein
- neuromyelitis optica spectrum disorder