g-NK cells express less of the daratumumab target CD38 and are more resistant to daratumumab-induced fratricide than cNK cells. Comparison of the percentage of CD38⁺ (A) and SLAMF7⁺ (B) unexpanded g-NK, cNK, and MM.1S cells (n = 4). Comparison of CD38 expression shown as (C) percentage of NK cells and (D) MFI for CD38⁺ NK cells before and after expansion between g-NK and cNK cells (n = 4). (E) Comparison of daratumumab-induced fratricide by expanded g-NK and cNK cells. (F) Representative histogram depicting the reduced CD38 expression of g-NK cells relative to cNK and MM.1S cells. To determine the differences in CD38 and SLAMF7 expression between unexpanded g-NK, cNK, and MM.1S cells, a one-way ANOVA was performed with Bonferoni post hoc testing to determine differences between individual cell types. Independent samples Student t tests were used to determine the differences in CD38 expression between g-NK and cNK cells before and after expansion. Independent samples Student t tests were also used to determine the differences in fratricide by expanded g-NK and cNK cells. Values are mean ± SEM. ***P < .001.