To overcome the dysfunction of potentially tumor-reactive T cells from patients with B-CLL, several approaches have been developed relying on the stimulation of B-CLL cells through the CD40 pathway, including the ectopic expression of CD154 on the leukemic cells, and aiming at the self-stimulation of these cells [14]–[17]. The gene discussed is CD40; the disease is B-cell chronic lymphocytic leukemia.