As reviewed elsewhere,8,12,15 immunotherapy using single-agent interferon-α (IFN-α; an endogenous activator of NK cells),8 multiple regimens of monotherapy with IL-2 (an activator of NK and T cell functions),28 hybrid chemo-immunotherapy with anti-CD33 conjugated to a chemotherapeutic agent29 or linomide (a synthetic NK cell activator),30 did not reduce relapse risk in phase III trials when administered to AML patients in the postconsolidation phase. This evidence concerns the gene IL2 and acute myeloid leukemia.