We observed more CD19 intron 10 retention in CD19neg relapsed samples from pediatric B-ALL patients treated with 19.BBz CAR T cells11,14 (n = 11), adult B-ALL patients treated with blinatumomab13 (n = 2), and adult LBCL patients treated with 19.28z CAR T cells29,30 (n = 6) (Fig. 2H, Supplementary Fig. 6E). The gene discussed is CD19; the disease is precursor B-cell acute lymphoblastic leukemia.