CXCL13 and neuromyelitis optica: In NMO patients, CXCL13 was correlated with onset age (r = .453, p = .026) (Figure 2c) and duration to the last relapse (in months) (r = −.577, p = .003) (Figure 2d), but not with relapse frequency (r = −.161, p = .454), disease duration (r = −.055, p = .798), or ARR (r = .126, p = .558).