Characteristic analysis of minimal residual disease screening markers in childhood acute lymphoblastic leukemia

Objective To analyze the screening markers of minimal residual disease (MRD) in children with acute lymphoblastic leukemia( ALL), and to evaluate its clinical application and express characteristic. Methods Thirty-five patients with childhood acute lymphoblastic leukemia treated in our hospital from 2008.11-2009.12 were enrolled into this study. Bone marrow samples were taken to isolate sing-nucleus cells. Four-color fluorochrome labeled monoclonal antibodies were applied to analyze the cell immunophenotypes when meet the demand like these: low expression of CD38, CD45; high expression of CD58,CD21, CD22; co-expression of CD34 and Cu, and the expression of abnormal chromosome related antigen CD66c. After staining of surface and intracellular antigen, sample should be detected for leukemia-associated immunophenotypes by four-color FCM with double parameters. The leukemic cell populations located in flow cytometry dot plot different from those of normal were considered to be the effective screening markers.Results Total of cases of 31 patients at least had one MRD marker, coverage is 88.6%. 21/35 (60%)had 2 or more than 2 selection markers; TdT/CD10/CD34/CD19 is the most common four-color combination, followed by CD38/CD10/CD34/CD19, CD45/CD10/CD34/CD19, other index is rare. Conclusion TdT/CD10/CD34/CD19 was the most common four-color selection markers should be as regular and preferred detection ones. Study showed the immune phenotype Pro-B is lack of effective selection markers. Two or more interest markers should be improved the accuracy of MRD significantly. Key words: Acute lymphoblastic leukemia; Minimal residual disease; Flow cytometry