Immunophenotype and relative telomere length of infused T cells. End of production T cells for patients UPN-02, UPN-03, and UPN-04, as well as cells from patient UPN-01 (after 9 stimulation cycles) were analyzed by flow cytometry after being thawed, washed, and stained with the antibodies shown. (A) Geometric mean fluorescence intensity (MFI) after subtracting the isotype control MFI and (B) percent positive cells. (C) Genomic DNA was harvested from CD3-selected apheresis PBMCs and from pre-infusion, ex vivo expanded CAR⁺ T cells for each patient. T cells from both attempts at expansion for UPN-01 were analyzed. Quantitative PCR was used to determine the amounts of telomeric DNA (T) and of a single-copy internal reference gene (S) for each sample. The relative mean telomere length of each cell population is represented by the T/S ratio. Data represent the mean of 2 assays, each performed in triplicate.