Background: Neuromyelitis optica (NMO) is characterized by severe optic neuritis and longitudinally extended transverse myelitis. A serum autoantibody against aquaporin-4 (AQP4), a water channel densely expressed on astrocytes, has been detected exclusively in NMO and the high-risk syndrome. Pathologically, an extensive loss of AQP4 with perivascular depositions of activated complements (C9neo) as well as immunoglobulins is seen in NMO lesions, and infiltration of neutrophils is not uncommon in those lesions.
OBJECTIVE: The serum of most neuromyelitis optica (NMO) patients contains autoantibodies (NMO-IgGs) directed against the aquaporin-4 (AQP4) water channel located on astrocyte foot processes in the perivessel and subpial areas of the brain. Our objectives were to determine the source of central nervous system (CNS) NMO-IgGs and their role in disease pathogenesis. METHODS: Fluorescence-activated cell sorting and single-cell reverse transcriptase polymerase chain reaction were used to identify overrepresented plasma cell immunoglobulin (Ig) sequences in the cerebrospinal fluid (CSF) of an NMO patient after a first clinical attack
Neuromyelitis optica (NMO; Devic’s disease) and the NMO spectrum disorders are idiopathic inflammatory demyelinating disorders that affect the central nervous system and have a predilection for optic nerves and spinal cord. The identification of NMO-IgG as a disease-specific marker and aquaporin 4 as the target antigen has renewed interest in NMO.