Enhanced DARA-mediated ADCC activity of CD38^KO NK cells against MM cell lines and primary MM cells. (A) Representative FACS analyses of CD38 expression of NK cells and myeloma cell lines. Each panel shows the mean fluorescence intensity (MFI). Isotype controls are depicted with filled histograms. (B-C) Representative data of cytotoxicity and DARA-mediated ADCC activity of paired CD38^WT and CD38^KO NK cells against myeloma cell lines and (D) a representative primary MM sample. (E) ADCC activity of paired CD38^WT and CD38^KO NK cells against primary MM samples (effector-to-target [E:T] ratio is 0.1:1) (F) Cytotoxicity of paired CD38^WT and CD38^KO NK cells against primary DARA-resistant MM cells in the presence of DARA.