– B-cell activating factor (BAFF), also known as BLyS, TALL-1, THANK, and TNFSF13B, is a transmembrane glycoprotein in the TNF ligand superfamily. BAFF is a cytokine and serves as a ligand for receptors TNFRSF13B (TACI), TNFRSF17 (BCMA), and TNFRSF13C (BAFFR). BAFF can promotes the survival, proliferation and maturation of B lymphocytes, which are key elements in the pathogenesis of systemic lupus erythematosus (SLE). This cytokine is encoded on TNFSF13B gene, and diverse single-nucleotide polymorphisms have been associated with susceptibility in diferent autoimmune disorders. BAFF is a transmembranal protein expressed on myeloid lineage and some epithelial cells, through diferent stimuli such as IFN-γ, IFN-α, interleukin (IL)-10, Toll-like receptors (TLR)-3, TLR-4 and TLR-7.