Licensed and nonlicensed NK-cell degranulation after HSCT. Donor and post-HSCT patient PBMCs (patients 1, 8, 9) were incubated with 721.221 target cells and measured for CD107a expression. Degranulation was assessed as the percentage of CD107a⁺ cells within NK populations expressing specific KIR. (A) Percentage of CD107a-positive cells within the NK cells exclusively expressing NS-KIR KIR2DL1 (left), S-KIR KIR2DL3 (middle), and S-KIR KIR3DL1 (right) from the healthy HLA-C1/C1, Bw4/Bw6 HSCT donor (no. 9), the HLA-C1/C1, Bw4/Bw6 patient at day +15, day +30, and day +200 after HSCT. Findings are representative of studies performed in 3 donor-recipient pairs. (B) The post-HSCT/pre-HSCT ratio of CD107a expression was compared in the patient at days +15 to +60 and days +100 to +200 after HSCT (n = 3). The paired Student t test was performed to compute the P value for these comparisons.