AQP4 and neuromyelitis optica: Raised levels of BAFF, APRIL, CXCL13, and IL-6 have also been detected in the CNS of patients with NMO, which are likely involved in recruiting and stimulating AQP4-ab producing cells (Vaknin-Dembinsky et al., 2010; Kaneko et al., 2018), facilitating pathogenicity (Bennett et al., 2015; Graf et al., 2021).