While the risks of B cell aplasia following CD19 CAR T cell therapy may be mitigated by immunoglobulin infusions, indefinite elimination of cells expressing AML-associated antigens such as CD33, CD123, CLL1/CLEC12A, or CD38 is likely to result in clinically intolerable myelosuppression. The gene discussed is CLEC12A; the disease is acute myeloid leukemia.