A patient with AML (FAB M4Eo) developed EBV-LPD 1.5 months after allogeneic BMT from his one locus-mismatched mother, the diagnosis being confirmed on day +82. Attempts to eradicate the monoclonally proliferating LPD using chemotherapy (VP16/dexamethasone) followed by two doses of EBV-specific CTL and one dose of unstimulated donor leukocytes were not successful. We assume delay of infusions (day +100, +107) and insufficient CTL cell doses (total 9.2 x 10(6)) may have been responsible for the poor outcome in this case.