Inclusion Criteria:

          -  Recipients of allogeneic stem cell transplantation for acute myeloid leukemia or
             myelodysplastic syndrome from a human leukocyte antigen (HLA) matched donor

          -  Relapsed of primary disease with 5% to 20% of blasts in the bone marrow by flow
             cytometry in the bone marrow with an clear leukemia-associated immunophenotype (If the
             patient received therapy to treat the relapse, he or she must have 5-20% residual
             blasts prior to enrollment on this study)

          -  Performance status KPS score >60% (ECOG 0-2)

          -  No increases in systemic immunosuppression in the prior four weeks other than to
             maintain therapeutic levels

          -  No systemic corticosteroid with a dose higher than 0.5mg/kg/day prednisone or
             equivalent

          -  No history of grade IV acute GVHD

          -  No new systemic immunosuppressive medications in the prior two weeks initiated due to
             GVHD

          -  Willingness to have bone marrow and peripheral blood collected as per the study
             protocol

          -  Must be able to give informed consent

          -  Age 18 or older

        Exclusion Criteria:

          -  Contraindication to receive IFN-γ including known hypersensitivity to
             interferon-gamma, E. coli derived products or any component of the product

          -  Subjects with a positive pregnancy test or who are breastfeeding

          -  For men or women of childing bearing potential (age < 50 without hysterectomy or
             oophorectomy or documented menopause), unwilling to use effective contraception for
             the duration of the study.

          -  Primary engraftment failure

          -  Active cardiac arrhythmias not controlled by medical management or current NYHA class
             II or higher congestive heart failure

          -  Active ischemic heart disease not well controlled with medications

          -  A seizure disorder not well controlled by medications

          -  Estimated GFR <30 mL/min

          -  AST/SGOT or ALT/SPOT > 5 x ULN

          -  Total bilirubin > 3 x ULN

          -  Chemotherapy (other than hypomethylating and/or venetoclax therapy) within the prior 4
             weeks

          -  Body surface area at or less than 1.5 m2, or greater than 2.5 m2 so as to minimize the
             variation in IFN-γ exposure based on differences in BSA.

          -  Patients less than 18 years old.

          -  Pregnant or breastfeeding patients.