Enhanced Detection of Multiple Myeloma Cells by Next-Generation Flow Cytometry Following Density Gradient Medium...

Area of Science:

• Hematology
• Clinical Chemistry
• Immunology

Background:

• Multiple Myeloma (MM) relapse is linked to measurable residual disease (MRD).
• Expanding MM therapies require more sensitive MRD detection methods for accurate response assessment.

Purpose of the Study:

• To enhance the efficiency and sensitivity of flow cytometry for MM MRD detection.
• To compare three pre-enrichment methods: erythrocyte bulk lysis (BL), density gradient medium (DGM) separation, and negative selection (NS).

Main Methods:

• Compared BL, DGM, and NS using 32 active MM and 122 remission MM patient samples.
• Evaluated pre-enrichment methods for efficiency, sensitivity, processing time, and cost-effectiveness.
• Assessed analytical sensitivity using limit of detection (LOD) and sample processing capacity.

Main Results:

• DGM separation allowed processing of larger white blood cell (WBC) quantities (>60 × 10⁶) compared to BL (20 × 10⁶).
• DGM achieved higher analytical sensitivity (LOD 5.2 × 10^-7) versus BL (LOD 2 × 10^-6).
• DGM offered shorter processing times and was more cost-effective than BL and NS, with NS being least suitable for clinical use.

Conclusions:

• Density gradient medium (DGM) separation is a cost-effective pre-enrichment method for MM MRD analysis.
• DGM significantly increases analytical sensitivity and reduces sample processing times.
• DGM enhances the clinical utility of flow cytometry for MM MRD detection.