Both CAR19 and CAR19.αPD1 T cells were cocultured with H292-CD19 cells for 24 hours. (A) The expression of PD-1, LAG-3 and TIM-3 was measured by flow cytometry. The percentage of PD-1-, LAG-3- or TIM-3-expressing CD4 T cells over total CD4+ T cells was shown in bar graphs (n=3, mean {plus minus} SEM; ns, not significant, P > 0.05; **P < 0.01). (B) The expression of PD-1 and LAG-3 in both CAR19 and CAR19.αPD1 T cells during the course of T cell expansion (post T cell activation and transduction).