NK cell repertoire diversifies with maturation and after CMV infection. (A) The box graphs show the NK cell repertoire diversity in PB samples collected from CBT recipients in the first 30 days (7 patients; 13 samples), days 31-60 (17 patients; 28 samples) and days 61-100 (19 patients; 25 samples). *P ≤ .05. Boxes represent median with minimum to maximum range. (B) Box graphs comparing the diversity of the NK cell repertoire, measured using the inverse Simpson index, in healthy adult donors who were CMV seropositive (left, n = 10) or CMV seronegative (right, n = 10). ***P ≤ .001. Boxes represent median with minimum to maximum range. Samples from CMV seropositive patients were collected after CMV reactivation. (C) Comparison of the phenotypic complexity of KIR⁺ and KIR⁻ NK cells from a representative healthy CMV seropositive adult donor using 2-dimensional t-SNE maps. Individual t-SNE maps show the expression of 29 different NK cell markers. Color scale indicates signal intensity, ranging from low (blue) to high (red) after arcsine transformation. Bar plots under each t-SNE map depict the frequencies of NK cells expressing each marker in the KIR⁺ and KIR⁻ NK cell populations from 10 CMV seropositive adults. *P ≤ .05; **P ≤ .01; ***P ≤ .001; ****P ≤ .0001. Bars represent median with interquartile range. (D) Box graphs comparing the diversity of the NK cell repertoire, measured using the inverse Simpson index, in KIR⁺ (red, n = 10) vs KIR⁻ NK cells (blue, n = 10) from CMV seropositive or seronegative adult PB donors. **P ≤ .01. Boxes represent median with minimum to maximum range.