Detection of Minimal Residual Disease in B Cell Acute Lymphoblastic Leukemia Using an Eight-Color Tube with Dried Antibody Reagents.

ABSTRACT

BACKGROUND: Flow cytometry is a powerful tool for the detection of minimal residual disease (MRD) of B cell precursor acute lymphoblastic leukemia (BCP-ALL) patients. However, the staining process and the choice of antibodies rely on laboratory expertise and may be source of variability or technical errors. Recently, Beckman Coulter commercialized a ready to use tube with dried format reagents for BCP-ALL MRD detection. The aim of this study is to evaluate the applicability of this tube and to compare it to a conventional (liquid format reagents) method. METHODS: Thirty-one samples from B ALL patients were analyzed 19 bone marrow (BM) aspirations, 10 peripheral blood (PB) samples and 2 cerebrospinal fluids at different stages of the follow-up. In addition, we tested 5 bone marrow samples mixed into non-pathological (control) bone marrow. The dried format tube included seven antibodies CD45Kro, CD58FITC, CD34ECD, CD10PC5.5, CD19PC7, CD38AA700, CD20AA750, with possibility of additional antibodies for blast markers identified at diagnosis. For comparison, a liquid format tube was prepared, and considered as the reference. RESULTS: This tube was validated for daily routine laboratory, with satisfying qualitative (MRD + or MRD-) and quantitative (MRD percentages) correlation with the reference tube. CONCLUSION: With this single dried format tube, we showed interesting results for BCP-ALL MRD detection in the aim of standardization and reliable interlaboratory results. It allows accurate MRD detection including low levels (10-4), and offers possibility to increase performance (supplementary antibody) within a preestablished effective antibody panel for BCP-ALL MRD. © 2018 International Clinical Cytometry Society.