CD33 and acute myeloid leukemia: To increase killing of more resistant blast subtypes, we combined mismatched ADAPT-NK cells with a CD16/IL-15/CD33 tri-specific engager (TriKE), previously used to target AML blasts.37 The expression of CD33 on AML blasts was high and addition of the TriKE resulted in significantly improved killing of AML blasts, even for more resistant samples and NKG2DL- LSC (figure 5E, F and online supplemental sFigure 4C).