Serum B-cell Activating Factor in Myecloperoxiase-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 6 5.02 ng/mL) and remission phases (3.60 6 3.83 ng/mL) were significantly higher than those in healthy controls (0.87 6 0.31 ng/mL) (P , 0.001, respec- tively). 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 5 0.320, P , 0.001) and erythrocyte sedimentation rate value (r 5 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. Key Indexing Terms: ANCA-associated vasculitis; MPO-ANCA; BAFF. (Am J Med Sci 2014;348(1):25-29.)