Variable frequencies of the different identified allo-HLA/peptide reactivities. Activated CD8⁺ donor T cells were sorted from PBMCs at the time of GVHD, expanded nonspecifically, and stained with the different functional tetramers conjugated with either PE or allophycocyanin, in combination with anti-CD8 Alexa 700. As a control, the CMV-pp65-NLV tetramer was included. In the dot plots, the CD8⁺ T cells are shown, and numbers in the different quadrants represent the percentage tetramer-positive CD8⁺ T cells.