- Acute myeloid leukemia/acute lymphoblastic leukemia, including biphenotypic acute leukemia or mixed-lineage leukemia: Must have < 5% morphologic marrow blasts in an evaluable marrow (> 25% of normal cellularity for age) collected less than one month prior to start of conditioning; patients persistently aplastic for greater than one month since completing last chemotherapy are also eligible with the approval of the principal investigator (PI) or designee