Flow-cytometric detection of minimal residual disease with atypical antigen combinations in patients with de novo acute myeloid leukemia

The immunophenotypic features in adult de novo acute myeloid leukemia (AML) patients at diagnosis using flow cytometry double marker analysis and the detection of minimal residual disease with atypical leukemia-associated ant igen combinations during remission were investigated. Fifty adult patients with de novo AML at diagnosis were studied. Bone marrow samples from 21 pat ients with AML were analyzed upon achievement of complete remission and dur ing continuous complete remission. Ten bone marrow samples of normal donors were also studied. CD34/CD13, CD34/CD33, CD33/CD7, CD33/CD10, CD33/CD19 an d CD33/TdT are the leukemia-associated antigen combinations used for the de tection of minimal residual disease. The outcome of 19 patients has been ev aluated. Of these 19 patients, 10 were found to be in immunophenotypic remi ssion (median follow-up after the study: 837 days, range 620-1343 days). On ly one patient in this group has relapsed so far. In the other nine patient s residual disease was detected. Seven of these patients developed systemic relapse following a median follow-up time of 86 days after the study (rang e 34-273 days), one received allogeneic bone marrow transplantation 70 days after the study, and another has been in complete remission and off chemot herapy for 36 months. The presence of cells with atypical antigen combinati ons identified at diagnosis in certain patients is valuable for monitoring the disease in remission. The persistence of such a population in remission has indicated the impending relapse in this study.