Following alloSCT, MHC class I HCMV-pp65 peptide-specific tetramer⁺ CD8⁺ cells are abundant within the expanded CD28^-CD8⁺, CD27^-CD8⁺, and CD11b⁺CD8⁺ T-cell subpopulations. (A) Relative to donor 01 PBMCs, there is an early and persistent expansion in the percentage of CD28^-CD8⁺ CD3⁺, percentage of CD27^-CD8⁺ CD3⁺, and percentage of CD11b⁺ CD8⁺ CD3⁺ T cells in the PBMCs of recipient 01 following alloSCT. The proportion of CD28^-CD8⁺ CD3⁺ T cells was similar in donor PBMCs and donor peripheral blood stem cells (PBSCs); CD27 and CD11b data were not available in donor 01 PBSCs. (B) Upper panels, donor 01; lower panels, recipient 01 at 22 months after alloSCT. Gated on CD8⁺ T cells. Results are expressed as percentage of CD8⁺ T cells. In recipient 01 MHC class I HCMV-pp65 peptide-specific tetramer⁺ CD8⁺ cells are abundant within the expanded CD28^-CD8⁺, CD27^-CD8⁺, and CD11b⁺ CD8⁺ T-cell populations and are predominantly CCR7^-CD8⁺. Results are representative of recipients 01 to 04.