CD57⁺/CD27^– T cells with respect to donor and recipient CMV serostatus. (A) Flow cytometry gating strategy use to identify CD57⁺/CD27^– T cells. (B) Fraction of CD57⁺/CD27^– population of CD4⁺ and CD8⁺ T cells with respect to CMV serostatus (D^–/R^–, D^–/R⁺, D^–/R^–, D⁺/R⁺). (C) Fraction of CD57⁺/CD27^– population of CD4⁺ and CD8⁺ T cells broken down by both CMV serostatus and posttransplant CMV reactivation status (PCR⁻ or PCR⁺). (D) Fraction of CD57⁺/CD27^– T-cell populations in relation to time of sample drawn from day of transplant. No significant temporal correlation was seen for the CD4 subset (r_s = 0.024, P > .05). There was a marginal increase in expression over time for the CD8 subset (r_s = 0.23, P = .035). (E) The fraction of CD57⁺/CD27^– CD4⁺ and CD8⁺ T cells from baseline (sample 1, x-axis) to repeat sample (sample 2, y-axis) taken at a mean of 93 days (28-218) later were compared for 35 patients with repeat samples. There was a significant correlation between the 2 populations over time for both the CD4⁺ (log-log axis, r_s = 0.90, P < .0001) and CD8⁺ T-cell subsets (r_s = 0.75, P < .0001). Statistical significance is denoted by *P < .05, **P < .01, ***P < .001, ****P < .0001.