Objectives: To investigate serum levels of B cell activating factor (BAFF) in Chinese patients with polymyositis (PM) or dermatomyositis (DM), and analyze the correlation of BAFF with autoantibodies and clinical phenotypes.
Methods: Serum BAFF levels of 28 PM patients and 30 DM patients (study group), and 25 matched healthy controls (control group) were measured by ELISA. Serum anti-Jo-1 antibody levels were also measured by ELISA in all the subjects. The results of the two groups were compared by unpaired t test and the relevance was analyzed by Pearson's correlation analysis.
Results: Serum levels of BAFF in PM/DM patients were significantly higher compared to healthy controls (P = 0.000), but there was no statistically significant difference between the PM and DM patients (P > 0.05). Patients with interstitial lung disease (ILD) had significantly higher serum BAFF level than the patients without ILD (P = 0.000) or the controls (P = 0.000). Serum BAFF levels of patients with positive anti-nuclear antibody (ANA) were significantly higher than those with negative ANA (P = 0.003). For patients with anti-Jo-1 antibodies, the serum BAFF levels were correlated with the serum concentration of anti-Jo-1 antibodies (r = 0.799, P = 0.006).
Conclusions: Serum levels of BAFF are increased in Chinese PM/DM patients. These findings indicate that BAFF may be possibly enrolled in the pathogenesis of PM/DM. Detecting serum BAFF levels could have some implication for the diagnosis and treatment of PM/DM.