CD56^dimDNAM-1^negNK cells are enriched in the peripheral blood of patients with hematologic malignancies. (A-B) NK cell proportions in peripheral blood of patients with HL or DLBCL compared with that of age- and sex-matched healthy control donors was determined via flow cytometry by gating on live CD3^negCD56^pos NK cells. Representative fluorescence-activated cell sorter plots (A) and the mean ± SEM of duplicate wells from 7 to 10 individual donors (B) from each group are shown. (C) NK cell subset distribution was determined by flow cytometry from healthy donor and HL and DLBCL patient samples. Results are shown as the mean ± SEM of subset frequencies within the whole lymphocyte population (left) or the NK cell population (right). (D) Graph shows the ratio of CD56^dimDNAM-1^pos over CD56^dimDNAM-1^neg NK cell as mean ± SEM. (E) CD56^brightDNAM-1^pos, CD56^dimDNAM-1^pos, and CD56^dimDNAM-1^neg NK cell subsets were purified from healthy donor and HL or DLBCL PBMCs and stimulated overnight in IL-12 (10 ng/mL), IL-15 (100 ng/mL), and IL-18 (50 ng/mL). The following day, cells were added to wells containing K562 target cells in a 10:1 effector:target ratio. After 4 hours of culture, cytotoxicity of NK cell subsets against K562 target cells was measured by fluorescence-activated cell sorter staining for Annexin V/PI. Results are shown as mean ± SEM from 4 individual donors run in duplicate and pooled from 2 independent experiments. Individual dots represent the mean value of duplicate wells. Data were analyzed with a 1-way ANOVA (B,D) or a 2-way ANOVA (C,E) followed by a Tukey multiple comparison post hoc test. *P < .05; **P < .01; ***P < .001; ****P < .0001.