TNFRSF13C and systemic lupus erythematosus: In this regard, an influence of BAFF, APRIL and BAFFR polymorphisms was observed on several immune-mediated conditions9–11, being BAFF GCTGT>A a shared insertion-deletion variant for multiple sclerosis, systemic lupus erythematosus (SLE), and rheumatoid arthritis9,12.