Significance of flow cytometry in the detection of minimal residual disease in patients with acute leukemia

Objective To investigate the clinical significance of flow cytometry (FCM) in the detection of minimal residual disease (MRD) in patients with acute leukemia (AL). Methods MRD in 19 patients with AL were detected by FCM with idio-differentiation antigen as marker, and the results were compared with those detected by traditional bone marrow cells morphology. Results Of 73 bone mallow samples, MRD were positive in 61 samples, including 16 samples with leukemia cells ≥0.05,45 samples with leukemia cells from 0.000 1 to 0.05, and 12 samples with leukemia cells 0.0001 (MRD negative). 14 patients were diagnosed as relapse by bone marrow cells morphology, of which 13 were continually positive in MRD and were diagnosed relapse 4～28 months later (11 months before traditional bone marrow cells morphology assay). The average sensibility and specificity for predicting relapse were 100% (6/6) and 7.7% (1/13) in CR 0.6～12 months group, 100% (6/6) and 28.6% (2/7) in CR 13～24 months group, 100% (2/2) and 80% (4/5) in CR more than 25 months group, respectively. Conclusions Relapse of AL can be predicted by MRD monitor with the use of FCM. If MRD was positive in the early phase of treatment, the risk of relapse was higher. The accuracy can be increased by means of continous and regular monitor, which have important clinical significance in guiding chemotherapy, predicting relapse and selecting individualized treatment.