Flow Cytometric Analysis of Bone Marrow Particle Cells for Measuring Minimal Residual Disease in Multiple Myeloma

SIMPLE SUMMARY: The hemodilution of bone marrow aspirates is the main factor affecting the reliability of the determination of the minimal residual disease (MRD) resulting in multiple myeloma (MM). A bone marrow particle cell (BMPL) enrichment assay may be applied to overcome the problems caused by the hemodilution of bone marrow aspirates and to improve the rate of myeloma cell detection. Assessment of BMPL samples could decrease the false-negative rate of the MRD assessed with routine bone marrow aspirates. This study validated that the BMPL was superior to the routine bone marrow aspirate samples in the MM and MRD analysis. ABSTRACT: Minimal residual disease (MRD) is one of the most relevant prognostic factors in patients with multiple myeloma (MM). However, the hemodilution of bone marrow (BM) aspirates, the most common preanalytical problem, is known to affect MRD detection. In the present study, we analyzed a preanalytical method for routine BM aspirates and a bone marrow particle cell (BMPL) enrichment assay and validated it as a reliable preanalytical method for flow cytometric MRD determination. A total of 120 BM samples were taken from 103 MM patients consecutively recruited; 77 BM samples had BMPL enrichment analysis and 99 BM samples were routinely analyzed. Then, the two different samples from patients with MM were sent for MRD detection using an eight-color flow cytometry. Our data showed that assessment of the BMPL enrichment samples attenuated the overestimation of MRD-negative assessed in the routine BM samples, which was mainly caused by hemodilution. In conclusion, the BMPL enrichment assay is a functional and practical preanalytical method for flow cytometric MRD analysis.