CD19 and B-cell chronic lymphocytic leukemia: Because NR4A3 was the most significantly upregulated exhaustion-related transcription factor gene examined in PRDM1 KO CAR T-cells after multiple episodes of antigen stimulation (P < 0.001, Fig. 5B) and NR4A3 is significantly elevated in hypofunctional NR/PR CLL patient CD19 CAR T-cells (P < 0.01, fig.