CTLA4 and acute myeloid leukemia: To confirm that the increased cytotoxic immune response of the anti-CD123 CAR T cells is due to the change in the capacity of the AML cells to induce CTLA-4 expression on the T cells as a result of its exposure to AZA, CTLA-4negative, and CTLA-4positive anti-CD123 CAR T cells, were separately co-cultured with MOLM-13 or OCI-AML3 AML cells that had been pre-treated with AZA for 8 days or with untreated cells.