Phenotypic and functional characteristics of CLL patient vs healthy donor NK cells. Frozen PBMCs obtained from CLL patients (n = 9) and healthy donors (n = 9) were thawed and rested overnight and then used for flow cytometric analysis. (A) Pooled data showing proportion of CD56⁺/CD3⁻ NK cells within the lymphocyte gate in CLL patients vs healthy donors. While gating on NK cells, further subgating was carried out to evaluate the proportions of CD56^bright (B) vs CD56^dim (C) NK cells, as well as the proportions of NK cells expressing CD16 (D), NKG2A (E), KIR (F), and CD57 (G). NK cell degranulation via CD107a expression (H) and IFNγ production (I) were evaluated in CLL patient samples and healthy donors upon triggering natural cytotoxicity by incubation with K562 targets (n = 9 for CLL and for healthy donors, respectively). (A-G,I) Unpaired Student t test used for comparison between CLL samples and normal donor samples. (H-I) Paired Student t test used for internal group comparisons. Error bars indicate the mean ± standard error of the mean. Statistical significance are determined as *P < .05, **P < .01, ***P < .001, and ****P < .0001.