Neuromyelitis optica (NMO) is an autoimmune inflammatory disease of the central nervous system that produces demyelinating lesions in spinal cord and optic nerve, and, to a lesser extent, in brain. Most NMO patients are seropositive for autoantibodies against aquaporin-4 (AQP4), a water-selective channel expressed in astrocytes throughout the central nervous system, as well as in epithelial cells in some peripheral organs including kidney and stomach [3]. Immunoglobulin G anti-AQP4 antibodies, called NMO-IgG (or AQP4-IgG), are pathogenic in NMO by a mechanism that involves binding to astrocyte AQP4, complement-dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC), and inflammation with a prominent granulocyte and macrophage response, which leads to secondary oligodendrocyte injury, demyelination and neuronal injury.
