TNFSF13B and diffuse large B-cell lymphoma: Since APRIL, unlike BAFF, requires concentration and aggregation by heparan sulfate proteoglycans to be active and is poorly detected in DLBCL peripheral blood samples despite a high concentration at the TAN/B-cell interface inside tumors [27], it is tempting to speculate that APRIL plays a preeminent role over BAFF in this system, thus arguing for the development of APRIL antagonist mAbs for the treatment of B-cell lymphomas [33].