Interpretation of interleukin-2 receptor alpha positive cells during induction chemotherapy for adult acute myelogenous leukaemia patients. 
To correlate clinical outcomes with the expression of interleukin-2 receptor alpha (CD25) positive cells during induction chemotherapy (IC) in adult patients with acute myeloid leukaemia (AML), we investigated the prognostic importance of subsets of peripheral blood (PB) CD45+CD25+ cells.  Seventy-five patients with newly diagnosed AML received the same initial IC; and serial PB samples were taken.  The gated CD45/CD25 cell populations were used to compare the intensity of immunophenotypic signals based on the treatment timeline.  Patients who responded poorly to IC demonstrated exceptionally higher levels of PB CD45+CD25+ cells by percentage (p = 0.003) or by absolute count (p = 0.046) on the seventh day (D + 7) of initial IC.  In addition, patients in complete remission (CR) (n = 61) demonstrated relatively lower levels of steady PB CD45+CD25+ after standard IC.  These results suggest that the expression of CD25 can be used to predict the response to IC during an early period of treatment.