CD57⁻CD56^dimCD16⁺ NK cells are phenotypically less mature than CD57⁺ NK cells. (A) Flow cytometry was performed on total PBMCs, and CD3⁻CD56⁺ NK cells were gated (as shown in supplemental Figure 1) and analyzed for expression of CD57 and CD56. Two representative donors are shown. (B-E) Flow cytometry was performed on total PBMCs, and CD56^dimCD16⁺ NK cells were gated on CD57⁺ and CD57⁻ cells that were assessed for expression of different markers. Representative histograms for each marker are shown (shaded area represents isotype-matched control Ig; thin line, CD57⁺; and bold line, CD57⁻). The percentage of cells expressing CD62L and CD27 (B) and KLRG1 (D) was determined on each subset. The gMFI of NKp46, NKp30, NKG2D (C) and CD16 is shown (E). ● represents CD57⁺; and ◇, CD57⁻. ***P < .0005. (B-E) P values were determined comparing CD57⁺ and CD57⁻ NK cells (n = 23, for KLRG1 n = 18 and for NKp30 n = 14).