Expansion of DLBCL patient T cells in the presence of idelalisib and VIPhyb significantly enhances their in vivo persistence following adoptive transfer to NSG mice. T cells from a heavily treated DLBCL patient were expanded in the presence or absence of idelalisib and/or VIPhyb for 14 days followed by transfer to irradiated NSG mice. Blood was analyzed 14 days posttransfer for the presence of human CD45⁺CD3⁺ cells. (A) Experimental outline. (B) Flow plots showing the phenotype of T cells on day 14 of expansion just prior to adoptive transfer. (C) Representative flow plots from the blood of NSG mice showing the frequency of human T cells. (D) Quantification of T-cell frequencies in NSG mice 14 days after adoptive transfer from 1 of 3 independent experiments. **P < .01; ***P < .001.