Peripheral blood NK cells from CMV⁺ individuals have several altered features. (A) tSNE, 2-dimensional plot of 8000 individual NK cells, with clusters (A-K) identified using unsupervised hierarchical clustering. (B) Mean percentage of CMV⁻ and CMV⁺ cells contributing toward each cluster. (C) Heat map of canonical adaptive NK cell markers and markers that distinguish this cluster from other cells. 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). (D) Selected GO terms using all markers upregulated within cluster C, adaptive NK cells, with an adjusted P < .05. (E) Within cluster A, CD56^dim NK cells, comparison of average gene expression values for CMV⁻ cells and CMV⁺ cells. Genes with a fold-change >1 are highlighted. (F) Summary schematic of NK cell populations identified by scRNA-seq. Markers highlighted in red represent downregulation within that population. Of note, the schematic is based on transcript levels that may not entirely correlate with protein expression.