High Quality Content by WIKIPEDIA articles! B-cell activating factor (BAFF) also known as tumor necrosis factor ligand superfamily member 13B is a protein that in humans is encoded by the TNFLSF13B gene. BAFF is also known as B Lymphocyte Stimulator (BLyS) and TNF- and APOL-related leukocyte expressed ligand (TALL-1) and the Dendritic cell-derived TNF-like molecule (CD257 antigen; cluster of differentiation 257).