Longitudinal phenotypic characterization of tetramer-positive CD3⁺ CD8⁺ T cells. Analysis of PBMCs was performed by 6-color flow cytometry in 2 ALL patients at defined time points after SCT. CD45RO, CD27, and CD57 phenotype of CD3⁺ CD8⁺ T-cell gated tetramer positive lymphocytes on samples from patient 1 is presented here. (A) CMVpp65₄₉₅/HLA-A*0201⁺ CD8⁺ T cells. (B) WT1/HLA-A*0201⁺ CD8⁺ T cells