CD19 CAR T–cell persistence by flow cytometry. PBMCs from patient blood were analyzed by flow cytometry at different time points after adoptive transfer. (A) Live cells were identified by staining with 7-amino actinomycin D (7-AAD) and then gated on CD3 (either fluorescein isothiocyanate [FITC] or allophycocyanin [APC] labeled), with dump antibodies anti-CD14 (either phycoerythrin [PE] or FITC labeled), and anti-CD16 (either PE or FITC labeled). (B) Anti-CD19scFv CAR Alexa Fluor 647 antibody was used for detection of CD19-specific CAR⁺ T cells. Percentages of the highest CAR-positive cells at the indicated time points in all NHL1 patients are depicted. (C) Erbitux (cetuximab)-biotin/streptavidin-PE was used for detection of CD19 specific CAR⁺ T cells. Percentages of the highest CAR-positive cells at the indicated time points in all NHL2 patients are depicted. (D) Time course for a representative patient sample from NHL1 shows CAR T cells at baseline and various points after adoptive transfer. (E) Time course for a representative patient sample from NHL2 shows CAR T cells at baseline and various points after adoptive transfer.