Although not specific for pediatric indications, several barriers exist for use of cellular therapies, particularly for acute myeloid leukemia (AML), ST, and central nervous system (CNS) tumors, including imperfect target antigens [18-20]. Unlike CD19, which is typically uniformly expressed by malignant B-ALL and B-cell lymphoma cells, target antigens for myeloid leukemias and solid or CNS tumors may not have uniform expression. Here, CD19 is linked to acute myeloid leukemia.