[Comparison of minimal residual disease in multiple myeloma patients detected by 8-color panels and next generation flow cytometry].

Objective

To compare the sensitivity of 8-color panels and next generation flow cytometry (NGF) for detecting minimal residual disease of multiple myeloma patients.

Methods

8-color-membrane antigens (8C-Mem) panel was built including CD45, CD38, CD138, CD19, CD56, CD81, CD27 and CD117 to identify the plasma cells, while 8-color-cytoplasmic antigens (8C-Cyto) panel was built including CD45, CD38, CD138, CD19, CD56, CD81, cKappa (cK) and cLambda (cλ) , and 8-color-two-tubes (8C-2tubes) panel were built including 8C-Mem and 8C-Cyto panels, the data of three groups was analyzed by Diva software. NGF uses Infinicyt software to fuse 8C-2tubes data to further analyze the expression of plasma antigens. Bone marrow aspiration obtained from 20 controls and 76 multiple myeloma patients who achieved complete remission were measured and analyzed.

Results

Positive MRD samples were discriminated in 88.2% of the specimen evaluated through either abnormal plasma cells (aPCs) or clonal plasma cells (cPCs) by NGF antigens panel, Among of them, consistency was 94.7%. The median percentage of cPCs was 0.3530%, The lowest sensitivity of NGF was 0.0003%. In 8-color panels, the positive MRD rates of 8C-Mem, 8C-Cyto and 8C-2tubes panels were 84.2%, 85.5% and 86.8%, respectively, which lower than that of NGF (P<0.001) . The positive MRD rate of 8C-Mem and 8C-Cyto panels were lower than that of 8C-2tubes panel (P<0.001) , and the positive MRD rate of 8C-Mem panel was lower than that of 8C-Cyto panel (P<0.001) . Sensitivity and specificity of NGF was higher than that of 8-color panels. 8C-2tubes panel has the best sensitivity, accuracy, negative predicted value, positive predicted value and specificity than other 8-color panels. However, huge data and low efficiency for analysis is the disadvantage. 8C-Cyto panel was the second choice, and 8C-Mem panel was the last.

Conclusions

Membrane and cytoplasmic light chain is a better method for multiple myeloma-MRD detection and NGF panel is an ideal approach. 8C-Cyto panel is recommended in 8-MFC groups.