Association of CAR product polyfunctionality with CD19 recognition and clinical outcome. (A) PSI of CAR T cells and CD4⁺ or CD8⁺ subset, ex vivo stimulated with CD19⁺ as compared with CD19⁻ cells (NGFR transfected). (B-E) Association between OR and product PSI, IFN-γ measured in product coculture with CD19⁺ cells, or major product T-cell subsets defined by flow cytometry. T naïve, central memory (cm), effector memory (em), and effector (eff) cells were defined by staining for CD45RA and CCR7. (F) Individual P values (Mann Whitney U test) corresponding to the strength of association of major product attributes with clinical response.