AQP4 and neuromyelitis optica: Through exposing astrocytes and oligodendrocytes from primary cultures and rat optic nerves for 24 h to (NMO)-IgG in the absence of the complement, researchers found the complement-independent effect of NMO-IgG/AQP4 antibody on astrocytes, with secondary damage to oligodendrocytes (Marignier et al., 2010).