CMV-specific CD8⁺ T cells in patients and donors. (A) After SCT, patients have significantly greater frequencies of CMVpp65₄₉₅/HLA-A*0201⁺ CD8⁺ T cells than donors and patients before SCT. Data from multiple time points after SCT are presented. (B) Longitudinal analysis of CMVpp65₄₉₅/HLA-A*0201⁺ CD8⁺ T cells after SCT in patient 4. HIV/HLA-A*0201 was used as a negative control for tetramer staining. Results are expressed as percentages of CD8⁺ T cells. (C) Longitudinal analysis of IFN-γ production by CD8⁺ T cells in post-SCT PB samples from patient 4 cultured for 6 hours with CMV peptide (top panel) or without peptide (negative control, bottom panel). Results are expressed as percentages of CD8⁺ T cells.