B Lymphoblastic Leukemia Minimal Residual Disease Assessment by Flow Cytometric Analysis

Among the most thoroughly evaluated modalities for the assessment of minimal residual disease (MRD) in B acute lymphoblastic leukemia (B-ALL) is multiparameter flow cytometry. Flow cytometric evaluation of MRD for B-ALL requires complete understanding of the immunophenotype of hematogones, the normal counterpart of leukemic B lymphoblasts. Assessment of multiple flow cytometry markers, in concert with each other in multidimensional histograms, is necessary to distinguish hematogones from malignant blasts. Emerging therapies targeting CD19 and other B-cell markers can disrupt the most frequently used MRD assessment, requiring a revised approach as the use of targeted therapies becomes widespread.