Since then, it has been suggested that the disruption of astrocytes by complement-dependent cytotoxicity (CDC) induced by NMO-IgG binding to AQP4 is the initial event of NMOSD, identified by using in vitro, ex vivo, and in vivo models [4,5,6,7,8,9,10,11] as well as by analyzing patients’ tissues [12,13]. Here, AQP4 is linked to neuromyelitis optica.