RecruitingPhase 2Drug trialInterferon-γ (IFN-γ) With Donor Leukocyte Infusion to Treat Relapsed Acute Myeloid Leukemia and Myelodysplastic Syndromes Post Allogeneic Hematopoietic Stem Cell TransplantationThis phase 2 study aims to confirm the efficacy seen in the prior phase 1 trial, and further contribute to this effort through the collection of leukemia cells pre- and post- in vivo IFN-γ therapy. As in the previously conducted phase 1 trial, this trial will test whether leukemia blasts were responsive to IFN-γ in vitro and in vivo, with single-cell RNA sequencing (scRNAseq) conducted to understand the transcriptomic changes induced by IFN-γ in leukemia cell subsets, including those with stem cell characteristics.