Sandwich ELISA quantitative detection kit for Human TNFSF13/APRIL in cell culture supernates, serum and plasma (heparin, EDTA).Tumor necrosis factor ligand superfamily member 13 (TNFSF13) also known as a proliferation-inducing ligand(APRIL) is a protein that in humans is encoded by the TNFSF13 gene. TNFSF13 has also been designated CD256(cluster of differentiation 256). The protein encoded by this gene is a member of the tumor necrosis factor ligand (TNF) ligand family. This protein is a ligand for TNFRSF17/BCMA, a member of the TNF receptor family. This protein and its receptor are both found to be important for B cell development. In vivo experiments suggest an important role for APRIL in the long-term survival of plasma cells in the bone marrow. Mice deficient in April showed a reduced ability to support plasma cell survival In vitro experiments suggested that this protein may be able to induce apoptosis through its interaction with other TNF receptor family proteins such asTNFRSF6/FAS and TNFRSF14/HVEM. Three alternatively spliced transcript variants of this gene encoding distinct isoforms have been reported. The TNFSF13 gene lies 878 bp downstream of the TNFSF12 gene on chromosome 17p13.1.