Dissecting the origin of the expanded KIR subsets. (A) Stratification of the cohort into CMV-seronegative (top, n = 48) and CMV-seropositive (bottom, n = 151) individuals. Red dots represent subsets with high relative frequencies (statistical outliers as defined in Figure 1B). (B) Shown are the frequencies of donors with 1 or more outliers according to CMV serostatus. (C) Representation of statistical outliers in CMV-seropositive (red dots) and CMV-seronegative (blue dots) donors originating from NKG2A⁺, NKG2C^-NKG2A^-, and NKG2C⁺ CD56^dim NK cell subsets.