NK cells from posttransplant recipients have reduced Tim-3 expression compared with normal paired donors, which correlates with decreased IFN-γ production. (A) PBMCs from normal healthy volunteers, normal pair donors, and posttransplant recipient patient samples (from time points of 3 and 6 months) were stained with anti-CD56, anti-CD3, and anti–Tim-3 mAb. Tim-3 expression was evaluated by FACS analysis within the gated CD56⁺/CD3⁻ NK-cell population (n = 4). (B) PBMCs from normal healthy volunteers, normal pair donors, and posttransplantat recipient patient samples (from time points of 3 and 6 months) were coincubated with the K562 target cell line at an E T ratio of 2:1 for 5 hours and intracellular IFN-γ levels were measured within the total CD56⁺/CD3⁻, Tim-3⁺, and Tim-3⁻ NK-cell populations via FACS analysis (n = 4; error bars represent SEM).