Background: Antibodies to aquaporin-4 (AQP4-Ab), known as NMO-IgG, are a sensitive and specific marker for neuromyelitis optica (NMO).
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.
BACKGROUND: Interferon-β-1b (IFNβ-1b) has been used to prevent exacerbation of relapsing-remitting multiple sclerosis (RRMS) including optic-spinal multiple sclerosis (OSMS) in Japan. We encountered 2 patients with OSMS with unexpectedly severe exacerbation soon after the initiation of IFNβ-1b therapy. The experience urged us to retrospectively review the patients with RRMS who had been treated with IFNβ-1b to identify similar cases.