Figure 6.

Serum levels of BLyS, APRIL, and HTs in healthy donors and patients with autoimmune diseases. (a) Serum concentrations of HTs (upper panel), BLyS (middle panel), and APRIL (lower panel) for each patient. Horizontal bars depict median values for each serum donor group: healthy donors (blue squares), patients with SLE (red triangles), and patients with RA (green inverse triangles). P values were determined by using Fisher's exact test. *P < 0.05, **P < 0.0001. (b) Bivariate plots showing serum levels of BLyS, APRIL, and HTs in healthy donors (blue squares), patients with SLE (red triangles), and patients with RA (green inverse triangles). For data plotting, samples with serum ligand levels below the LOQ were assigned values equal to half the LOQ for each assay (0.156, 0.39, and 1.0 ng/ml for HT, BLyS, and APRIL, respectively). APRIL, a proliferation-inducing ligand; BLyS, B-lymphocyte stimulator; HT, heterotrimer; LOQ, limit of quantitation; RA, rheumatoid arthritis; SLE, systemic lupus erythematosus.