Serum and cerebrospinal fluid (CSF) concentrations of CXCL13 are reportedly elevated in NMO patients during relapse; furthermore, CXCL13 levels have a higher trend in NMO than in MS (Alvarez et al., 2013; Festa et al., 2009; Quan et al., 2013; Zhong et al., 2011). Here, CXCL13 is linked to neuromyelitis optica.