Serum B-cell activating factor in myeloperoxiase-antineutrophil cytoplasmic antibodies-associated vasculitis.

BACKGROUND: In this study, the serum B-cell activating factor belonging to tumor necrosis factor family (BAFF) levels in patients with myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) were measured, and their clinical significance was further analyzed. METHODS: One hundred twenty-one patients with MPO-AAV were enrolled in this study. Eighty-three patients had active vasculitis and 38 were in remission. Fifty-five healthy individuals were used as healthy controls. The levels of serum BAFF were assessed using commercial available enzyme-linked immunosorbent assay kits. The correlations between serum BAFF and Birmingham Vasculitis Activity Score, erythrocyte sedimentation rate and MPO-ANCA were further evaluated. RESULTS: The levels of serum BAFF of patients with MPO-AAV in both active (6.06±5.02 ng/mL) and remission phases (3.60±3.83 ng/mL) were significantly higher than those in healthy controls (0.87±0.31 ng/mL) (P<0.001, respectively). The serum BAFF levels in patients with active vasculitis were significantly higher than those in remission (P<0.001). Serum BAFF levels were significantly correlated with Birmingham Vasculitis Activity Score (r=0.320, P<0.001) and erythrocyte sedimentation rate value (r=0.311, P<0.01) in all patients, but no correlation was found between the levels of serum BAFF and MPO-ANCA. Using receiver-operating characteristics statistics, the cutoff values of serum BAFF level for indicating the presence of MPO-AAV and active vasculitis were 1.58 and 4.20 ng/mL, respectively. CONCLUSIONS: The levels of serum BAFF were elevated in patients with MPO-AAV and associated with disease activity, but they were not related with the levels of MPO-ANCA.