TNFSF13B and neuromyelitis optica: Median serum BAFF levels in the 16 NMO patients using immunosuppressive agents (671.66 pg/ml; range, 278.14–1,389.76) was lower than those of the other eight NMO patients (1,243.36 pg/ml; range, 685.09–1,942.81) (t = −3.325, p = .003) and the controls (Z = −2.188, p = .029).