AQP4 and neuromyelitis optica: The detection of AQP4‐Ab is essential as it justifies consideration of long‐term immunosuppression (Kimbrough et al., 2012; Sellner et al., 2010; Trebst et al., 2014), as interferon‐beta (IFN‐beta), natalizumab and fingolimod have been reported to be inefficacious or even harmful when used for the NMO treatment (Kowarik, Soltys, & Bennett, 2014).