TNFSF13B and neuromyelitis optica: In NMO patients, BAFF levels were not correlated with onset age (r = .328, p = .118), relapse frequency (r = .163, p = .447), disease duration (r = .125, p = .561), ARR (r = −.202, p = .343), or duration to the last relapse (in months) (r = .267, p = .208).