Some important aspects in NMO pathophysiology revealed in this study were findings of either necrosis of astrocytes associated with complement deposition in their plasma membrane, findings of an apoptosis-like process in astrocytes (clasmatodendrosis), which was associated with internalization of AQP4 and AQP1, and astrocyte apoptosis in the absence of complement activation. Here, AQP4 is linked to neuromyelitis optica.