Minimal Residual Disease in Acute Myelogenous Leukemia with PML/RARα or AML1/ETO mRNA and Phenotypic Analysis of Possible T and Natural Killer Cells in Bone Marrow

Here we studied minimal residual disease (MRD) of patients with acute myeloid leukemia (AML) who have PML/RARα or AML1/ETO as well as the phenotypic analysis of lymphocyte subsets involved in antitumor immunity. Eight patients in long-term (LT; 3 to 15 years) and 15 patients in short-term (ST; up to 3 years) remission were studied. Using the reverse transcription-polymerase chain reaction (RT) assay, the limit of detection was 10-5 to 10-6 for PML/RARα transcript and 10-4 to 10-5 for the AML1/ETO transcript. Simultaneously, T lymphocyte subsets and NK cells from the peripheral blood (PB) and bone marrow (BM) were investigated by flow cytometric analysis. Four of the eight patients in LT and 7 of the 15 patients in ST remission were MRD-positive. Although all MRD-positive patients in LT remission are still until now event-free, 3 of the 7 MRD-positive (MRD+) patients in ST remission soon relapsed. The total populations of CD4+, CD8+ and CD56+ [possible T-cell and natural killer (T/NK) populations] in the B...