Kinetics of disease response in a patient with CMML following TK⁺ DLI. Patient 8, affected by chronic myelomonocytic leukemia (CMML) in relapse after allogeneic HSCT, was treated with multiple TK⁺ DLI (arrows). Absolute numbers of circulating TK⁺ cells, quantified by FACS analysis, are shown as ■. Below the level of FACS sensitivity, quantitative PCR values are reported. Percentage of malignant cells in the bone marrow (black sectors of pies) was assessed by analyses of host karyotype and quantification of myelodysplastic precursors. Disease response strictly correlated with the kinetics of expansion of TK⁺ cells and persisted after ganciclovir administration for cGvHD. TK⁺ cells were detectable by PCR during a complete remission long-term follow-up up to 110 months.