Microfluidic-based Affinity Isolation of Rare Cells from Peripheral Blood for Minimal Residual Disease Monitoring

Minimal residual disease (MRD) quantifies the presence of cancer cells in the blood or bone marrow and is the most powerful predictor of patients’ prognosis. We report on a microfluidic-based MRD (MF-MRD) assay that allows for frequent evaluation of blood for the presence of circulating leukemia cells (CLCs). The microfluidic chip affinity selects B-lineage cells, including CLCs using anti-CD19 antibodies poised on the wall of the microfluidic chip. Affinity-selected cells are released from the surface and are subjected to immunophenotyping to enumerate the CLCs, fluorescence in situ hybridization (FISH), and/or molecular analysis of their mRNA or gDNA. The assay was evaluated during the longitudinal testing of 20 pediatric patients throughout induction and consolidation therapy. The 116 tests were performed using MF-MRD using peripheral blood while only 41 standard-of-care were completed with multiparameter flow cytometry (MFC-MRD) using a bone marrow aspirate. While 57% MF-MRD tests were MRD(+), MFC-MRD test positivity was only 34%. The MF-MRD offered the advantage of efficient processing of small volumes of blood (2 mL), which is important in the care of pediatric patients, especially infants. The minimally invasive means of blood collection for MRD testing are a valuable alternative to MRD assessment from bone marrow aspirate collected via invasive bone marrow biopsy. In this presentation, we will report on the operational parameters of these devices and systems, show examples of molecular analysis of CLC that can be garnered from these biomarkers to aid in treatment of pediatric B-ALL patients.