In vivo CAR T-cell expansion and persistence. (A-B) CD8⁺ (A) and CD4⁺ (B) CAR T-cell peak expansion (cells/µL) by flow cytometry after CART1 and CART2. Gray lines connect paired values between identical patients. (C,E) CAR T-cell peak expansion by flow cytometry categorized by best response (C) and pre-CART1 lymphodepletion (E). CAR T-cell persistence by qPCR (CAR transgene copies/µg of DNA) categorized by best response (E) and pre-CART1 lymphodepletion (F). Dashed lines, limit of detection. (A-C,E) Bold horizontal lines, median; box, IQR; vertical lines, quartiles ± 1.5 × IQR. (D,F) Bold lines, polynomial regression lines using the LOESS method, shaded areas, 95% CI of the LOESS estimates.