Mice with BCR/ABL driven chronic myeloid leukemia display an increase in PD-1+ CD4+ T cells [18] and to test whether this observation could be expanded to other myeloid malignancies such as acute myeloid leukemia (AML) we transplanted bone marrow (BM) cells from an MLL-ENL driven AML mouse into sublethally irradiated recipients. The gene discussed is MLLT1; the disease is acute myeloid leukemia.