The level of minimal residual disease (MRD) during treatment is the most important prognostic factor in children with acute lymphoblastic leukemia (ALL). Currently, Flow cytometry is aceptable in the world wide because of hight sensitive but it is still very new in Vietnam. Ojective: 1/ Detect the combinations of leukemia associated phenotype (LAIP) for MRD monitoring of children with B precusor acute lymphoblastic leukemia. 2/ Evaluate initially MRD with detected panels. Material and method: 104 children were diagnosed B precusor ALL by morphology and immunophenotyping including 87 patients for first ojective and 17 patients for second ojective. Analyse immunophenotyping on Facs Calibur 3 colors. Results and discussion: 1/ The combinations of LAIP for monitoring MRD on Flow Cytometry 3 colors: CD20/CD10/CD19
CD34/CD45/CD19
CD34/CD38/CD19
CD34/CD123/CD19
CD34/CD13 or CD33/CD19 for myeloid cross lineage expression CD13+ or/CD33+ at diagnosis. 2/ There were significantly different between morphology and MRD on flow cytometry: On day 14 induction, all patient have got complete remission (CR) by morphology but 100 percent all of them have MRD positive
Day 28 induction CR 100 percent by morphology but only 33.3 percent patient have MRD0.01 percent but all of them have complete remission by morphology. These results show that the complete remission is not only by morphology, flow cytometry is currently the best immunophenotype-base method to monitor MRD in ALL.