title: Current concept of neuromyelitis optica (NMO) and NMO spectrum disorders.
abstract: Neuromyelitis optica (NMO) has been described as a disease clinically characterised by severe optic neuritis (ON) and transverse myelitis (TM). Other features of NMO include female preponderance, longitudinally extensive spinal cord lesions (>3 vertebral segments), and absence of oligoclonal IgG bands . In spite of these differences from multiple sclerosis (MS), the relationship between NMO and MS has long been controversial. However, since the discovery of NMO-IgG or aquaporin-4 (AQP4) antibody (AQP4-antibody), an NMO-specific autoantibody to AQP4, the dominant water channel in the central nervous system densely expressed on end-feet of astrocytes, unique clinical features, MRI and other laboratory findings in NMO have been clarified further. AQP4-antibody is now the most important laboratory finding for the diagnosis of NMO. Apart from NMO, some patients with recurrent ON or recurrent longitudinally extensive myelitis alone are also often positive for AQP4-antibody. Moreover, studies of AQP4-antibody-positive patients have revealed that brain lesions are not uncommon in NMO, and some patterns appear to be unique to NMO. Thus, the spectrum of NMO is wider than mere ON and TM. Pathological analyses of autopsied cases strongly suggest that unlike MS, astrocytic damage is the primary pathology in NMO, and experimental studies confirm the pathogenicity of AQP4-antibody. Importantly, therapeutic outcomes of some immunological treatments are different between NMO and MS, making early differential diagnosis of these two disorders crucial. We provide an overview of the epidemiology, clinical and neuroimaging features, immunopathology and therapy of NMO and NMO spectrum disorders.
authors.affiliation: Department of Neurology, The Walton Centre for Neurology and Neurosurgery, Liverpool, UK.
authors.forename: Anu
authors.initials: A
authors.lastname: Jacob
authors.forename: Andrew
authors.initials: A
authors.lastname: McKeon
authors.forename: Ichiro
authors.initials: I
authors.lastname: Nakashima
authors.forename: Douglas Kazutoshi
authors.initials: DK
authors.lastname: Sato
authors.forename: Liene
authors.initials: L
authors.lastname: Elsone
authors.forename: Kazuo
authors.initials: K
authors.lastname: Fujihara
authors.forename: Jerome
authors.initials: J
authors.lastname: de Seze
mesh_terms: D051401:Aquaporin 4 / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000276:immunology; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008279:Magnetic Resonance Imaging; D009471:Neuromyelitis Optica / Q000150:complications / Q000453:epidemiology / Q000473:pathology / Q000503:physiopathology / Q000534:rehabilitation* / Q000628:therapy*; D055502:Secondary Prevention
chemical_list: D051401:Aquaporin 4; D001323:Autoantibodies; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents
keywords: Multiple Sclerosis; Myelopathy; Neuroimmunology; Neuroophthalmology; Neuroradiology