Friebus–Kardash J, et al. – Analysts studied the relationship between SLE disease manifestations and serum levels of B–cell activating factor (BAFF), immunoglobulin G (IgG) anti–BAFF and BAFF–IgG complexes. In systemic lupus erythematosus (SLE) patients, a correlation between BAFF–IgG complexes and disease activity was observed. This outcome indicated a pathogenic role of BAFF–IgG complexes in SLE.