A fraction of peripheral blood NK cells is a population of type I IFN-responding cells. (A) Dot plot (left) of selected markers of interest within unstimulated cells only (columns) across the different clusters (rows). The size of the dot represents the percentage of cells expressing the markers, and the color encodes the average scaled expression values. Heat map (right) of same markers of interest within unstimulated cells only. Clusters are plotted in columns, and genes are shown in rows. Gene expression is color coded using average scaled expression values per cluster, based on a z-score distribution, ranging from low expression (purple) to high expression (yellow). (B) Comparison of average gene expression values (calculated in unstimulated cells only) for cluster 3 and grouped CD56^dim clusters (clusters 0, 1, and 2). The markers shown differentiate CD56^neg and CD56^dim blood NK cells by flow cytometry.⁴⁸  *Markers that are not consistent with flow cytometry. (C) Comparison of average gene expression values for cluster 3 between unstimulated and IL-2–stimulated cells. Genes with a fold change >0.5 and Bonferroni-corrected P < .05 are highlighted. (D) Heat map (right) of top 20 markers which define cluster 3 within unstimulated cells only. Format and expression scale are as described for the heat map in panel A. (E) Selected GO terms using all conserved markers upregulated or downregulated within this cluster with an adjusted P < .05.