Reconstitution of HCMV-specific CD8⁺ and CD4⁺ T cells in a patient after allogeneic transplantation of stem cells from a matched unrelated donor and reduced conditioning therapy.

Peptide-specific CD8⁺ and protein-specific CD4⁺T cells were analyzed by intracellular IFN-γ staining with flow cytometry after specific stimulation. The data show a massive initial expansion of HCMV-peptide–specific, HLA-A*0101–restricted CTLs, and later, of protein-specific CD4⁺ T cells in patient 14, who received a transplant from a matched unrelated donor after reduced conditioning treatment. A maximum of 14.8% of all CD8⁺ T cells were directed against a single HCMV peptide on day 63 after STC. Numbers represent the percentage of IFN-γ–producing CD3⁺CD8⁺ and CD3⁺CD4⁺cells in the lymphocyte gate.