CD8⁺ T-cell differentiation and cytotoxicity in patients with and without granulocyte therapy. (A) Rapid switch from naïve to memory phenotype was observed during expansion of CD8⁺ T cells in CBT patients receiving granulocytes (n = 2; patients 3 and 4). In contrast, only 6% to 27% of CB CD8⁺ T cells switched to memory phenotype at 30 days after transplantation in those not receiving granulocytes. (B) CD8⁺ T cells during early expansion acquired cytotoxic function (CD107a) on anti-CD3 stimulation. CD107a was significantly higher in index patients compared with the adult control. In contrast, a patient who underwent CBT without granulocyte transfusion had (low) CD107a, similar to the control.