TNFSF13B and B-cell chronic lymphocytic leukemia: Besides contribution to B cell activation, proliferation and plasma cell differentiation, autocrine secretion of tumor necrosis factor (TNF) superfamily (TNFSF) members BAFF (TNFSF13B) and APRIL (TNFSF13) have been described to prevent B chronic lymphocytic leukemia (B-CLL) cells from apoptosis (9).