Flow cytometric detection of minimal residual disease in B-lineage acute lymphoblastic leukemia by using "MRD lite" panel

Background: Normal B lymphoid precursors that express CD19, CD10, and/or CD34 are highly sensitive to corticosteroids and after two weeks of remission-induction therapy, they form less than 0.01% of the bone marrow population. More than 0.01% of such cells indicate minimal residual disease (MRD). MRD "lite" panel uses only three antibodies, namely CD19, CD10, and CD34 for MRD detection in cases of B-lineage acute lymphoblastic leukemia (B-ALL) expressing CD19, CD10, and/or CD34 by flow cytometry.

Methods: Fifteen cases of B-ALL were studied for MRD at Day 19 of remission-induction therapy by employing a simplified MRD detection protocol using a 3-color fluorochrome conjugated antibody panel (CD19, CD10, and CD34) on bone marrow aspirate samples.

Results: All cases at diagnosis expressed CD19, CD10, and CD34. Of fifteen patients, five (33.33%) were MRD negative with less than 0.01% of mononuclear cells and remaining ten cases (66.66%) were MRD positive, with the level of 0.01% to less than 0.1% cells.

Conclusion: The MRD assay used in this study is a simplified method for detecting MRD at Day 19 of remission-induction therapy for B-lineage ALL. This MRD assay is an effective and useful methodology in cases of B-ALL expressing CD19, CD10, and/or CD34 by flow cytometry.