Significance of FCM-DNA measurement in detecting minimal residual disease in leukemia

Using flow cytometry (FCM), we measured the DNA content of bone marrow from 25 patients with acute leukemia (AL) in complete remission (CR) and followed them up for 0.5 to 1 year. Five of 13 patients in early relapse had normal DNA index (DI), while the remaining 8 showed DNA aneuploidy 1.5 to 5 months (mean 2.6 months) before relapse. The relapse rate was higher in CR patients with DNA aneuploidy (88.9%) than in those with normal DI (31.3%, P less than 0.05). Intensive chemotherapy was helpful to prolong CR duration in CR patients with DNA aneuploidy. DNA measurement by FCM was considered a reliable method for detecting minimal residual disease (MRD), and the appearance of DNA aneuploidy might predict a relapse of CR.