AQP4 and Autoimmunity: Kim et al. (2012) suggested that brain MRI abnormalities in AQP-4 autoimmunity are typically localized in the periependymal portions where AQP-4 is highly expressed. Furthermore, reports (Viegas et al., 2009; Samart and Phanthumchinda, 2010) have shown that hypothalamic lesions tend to be more extensive in seropositive AQP-4 NMO patients.