Abstract: Objective To study the expression of B-cell activating factor (BAFF) in the serum and cerebrospinal fluid of patients
with neuromyelitis optica (NMO). Methods Clinical data were collected from 44 patients with NMO and 38 patients with
multiple sclerosis (MS). Thirty healthy controls and 15 controls with noninflammatory neurological diseases were also
recruited. The concentration of BAFF in the serum and cerebrospinal fluid were measured by enzyme-linked immunosorbent
assay (ELISA). Results The mean serum BAFF level was 250.2±126.9 pg/ml in NMO patients, 249.6±130.7 pg/ml in MS patients,
and 222.9±126.1 pg/ml in the control subjects, showing no significant difference among the 3 groups (P>0.05). The mean BAFF
level in the CSF was significantly higher in NMO patients than in MS patients (525.8±230.0 pg/ml vs 298.4±141.9 pg/ml, P<0.05),
and higher in MS patients than in the control subjects (141.4±76.2 pg/ml, P<0.05). Both NMO and MS group showed a positive
correlation between EDSS scores and CSF BAFF level. But in NMO patients, CSF BAFF level was not associated with
AQP4-antibody titer. Conclusion BAFF in the CSF may be a useful biomarker for a differential diagnosis of NMO from MS
and has an important value in evaluating the disease severity.