Detection of minimal residual disease in children with acute promyelocytic leukemia by flow cytometry.

Objective:To investigate the clinical significance of minimal residual disease (MRD) in children with acute promyelocytic leukemia (APL) detected by flow cytometry (FCM).Methods:The expression of CD13, CD33, CD34 and TdT in the bone marrows of 36 APL patients in initial stages and in remission using FCM.All cases were given AS2O3 daily continuously until complete remission (CR).Results:In 36 cases APL patients in initial stage, the expression of CD13 63.88% (23/36) and CD33 80.55% (29/36) was significantly higher than those in controls (P0.05), but few CD34 and TdT expression; the expression of CD13 and CD34 reached 10‰ in CR stage after treatment by AS2O3, the expression of CD13 and CD33 in the other 2 cases reached over 10%~20%, and relapsed within 3 months.Conclusion:The detection on expression of CD13 and CD33 by FCM in APL can predict relapse.The results of FCM analysis could improve the sensitivity of MRD detection and estimate the prognosis of APL patients.Co-expression of CD13 and CD33 might indicate poor outcome of APL.