Finally, TE cells were the subpopulation of CART cells that expanded the most during culture: the amplification factor for TE was above 75 for HDs and the strongest proliferation was detected for untreated CLL patients [day 20: 296-fold expansion (IL-7/IL-15), 405-fold expansion (IL-2)]. This evidence concerns the gene IL2 and B-cell chronic lymphocytic leukemia.