[Devic's neuromyelitis optica and related neurological disorders]

Devic's neuromyelitis optica (DNMO) is a demyelinating and inflammatory disease of the central nervous system (CNS) essentially restricted to the spinal cord and the optic nerves. It is a rare disorder. Since the first description by Eugène Devic in 1894, the relationship between DNMO and multiple sclerosis (MS) has been controversial. Recent clinical, epidemiological, pathological and immunological data suggest that MS and DNMO are distinct entities. This distinction between DNMO and MS is however crucial, as prognosis and treatment are indeed different. The clinical course of NMO deteriorates rapidly without appropriate treatment. Severe disability develop during attacks but is not driven by a progressive phase. Only early immunosuppressive treatment seems effective in NMO, and the standard immunomodulator treatments for MS (e.g., interferon-beta and glatiramer acetate) appear ineffective, and even positively harmful. DNMO is now considered to be an auto-immune, antibody-mediated disease especially since the identification of a specific serum autoantibody, NMO-IgG directed against Aquaporin-4. This antibody was initially proposed to differentiate DNMO and MS. Furthermore, NMO-IgG have enlarged the clinical spectrum of DNMO and could also be helpful to predict relapses or conversion to DNMO after a first episode of longitudinally extensive transverse myelitis or isolated optic neuritis. Finally, NMO-IgG, which seems to be directly pathogenic, might be a clue for a better understanding of intimate DNMO immunopathology.