CD33 and acute myeloid leukemia: Since the introduction of bispecific mAb targeting CD16 on NK cells and CD30 on Hodgkin’s lymphoma more than two decades ago [86], bi-specific mAb constructs have been engineered to engage CD16 on NK cells and various tumor antigens including; CD19 and HLA class II for B cell malignancies [87,88], CD30 for Hodgkin’s lymphoma [89], epidermal growth factor receptor (EGFR) [90], which is overexpressed in several epithelial cancer types, HER2 for breast cancer [91], CD33 for AML [92,93] and EPCAM for carcinomas [94].