NKG2A expression is increased in recipients of unrelated transplants, irrespective of graft manipulation, and is inversely correlated with KIR expression. Donor or day +100, donor-derived recipient PBMCs from UBM or TCD transplants were labeled with the directly conjugated mAb Z199, which stains NKG2A. The means, 25th to 75th percentile ranges, and extreme values of the percentages of CD56⁺/CD3^- cells expressing NKG2A by flow cytometry are shown in the box plot on the left. Results are presented for donors (n = 71) or recipients (n = 70). The same cells were stained with a cocktail of directly conjugated mAbs KIR (DX9, EB6, GL183, and FES173, which stain CD158e, CD158a, CD158b, and CD158i, respectively). The percentage of NKG2A recovery was calculated as a ratio of the percent expression on recipient NK cells over that on donor NK cells (R/D) and plotted on the x-axis versus the R/D ratio of total KIR recovery (right). There was no difference between recipients of UBM or TCD transplants, so data are presented for both transplant types.