Expression of CD25+ Cell Subsets after Induction Chemotherapy in Adult Patients with Acute Myeloid Leukemia.

An attempt was made to correlate clinical outcomes with specific patterns of the expression of CD25+ cells after induction chemotherapy (IC) in adult patients with acute myeloid leukemia (AML). Seventy-five newly diagnosed AML patients received the same initial IC and serial bone marrow (BM)- or peripheral blood (PB)-samples were taken. The gated CD45/CD25/CD4 cell populations were used to compare for the intensity of immunophenotypic signals and the different cell subsets, according to the treatment timeline. As one of the best predictive prognostic parameters, patients who responded poorly to IC showed exceptionally higher levels of PB CD45+CD25+ cells on days 7 (P=0.002) and 21 (P=0.05) post-IC. The results of patients in complete remission (CR)(n=61), as well as those of the patients who showed continuous CR, showed relatively lower levels of PB CD45+CD25+ and higher CD4+CD25+ regulatory T cells in the steady PB after the standard IC, which was accurately discernible in every patient and in normal healthy individuals (n=21). We found considerably lower expression levels of BM/PB CD4+CD25+ regulatory T cells in the patients. These results suggest that this tool can be used to predict the outcome of adult AML patients at an early period in treatment.