OBJECTIVETo elevate the prognostic value of minimal residual disease (MRD) detection by four-color flow cytometry with the antibody panel in childhood B-cell acute lymphoblastic leukemia (B-ALL).

METHODSThe clinical data of 183 children with newly-diagnosed acute B-ALL and who accepted MRD detection between October 2010 and March 2012 was retrospectively reviewed. According to the detection time and result of MRD, the 183 children were classified into four groups: MRD negative (n=37) and positive (n=18) in the induction chemotherapy and MRD negative (n=113) and positive (n=15) in the maintenance chemotherapy.

RESULTSDuring both induction and maintenance chemotherapy, the percentage of patients at high and median risk in the MRD positive group was higher than in the MRD positive group (P<0.05). In the maintenance chemotherapy group, the 3- year cumulative incidence of relapse in MRD positive patients was higher than negative patients (P=0.04). The Cox's proportional hazards regression analysis showed that insensitive reaction for prednisone (RR=1.005, 95%CI: 0.864-1.170, P=0.032), bone marrow morphology that did not meet M1 on the 15th day (RR=6.454, 95%CI: 2.191-19.01, P=0.002) and MRD≥0.01% (RR=1.923, 95%CI: 0.750-4.933, P=0.043) were risk factors for relapse in children with B-ALL.

CONCLUSIONSThe four-color flow cytometry with the antibody panel can distinguish from MRD positive patients from negative patients with B-ALL. The result of MRD detection, as prednisone sensitivity and bone marrow morphology on the 15th day, is also a independent prognostic factor in children with B-ALL.