iPEP of MRD vs diagnostic MM clonal PCs (n = 40). (A) Detailed immunophenotypic features of paired diagnostic vs MRD clonal PCs from 40 MM patients. All markers were evaluated in all 40 cases at both time points (diagnosis vs MRD). Notched boxes represent the 25th and 75th percentile values of the ratio between the amount of antigen mean fluorescence intensity expression per paired MRD/diagnostic BM clonal PCs; the dot in the middle and vertical lines correspond to the median value and both the 10th and 90th percentiles, respectively. (B) Representative bivariate dot-plots for the top 5 overexpressed markers in MRD vs diagnostic BM clonal PCs are shown (CD29, CD54, CD138, CD44, CD49e), as well as the corresponding iPEPs for each of the 5 representative patients. The iPEP of diagnostic BM clonal PCs is represented by 1 and 2 standard deviation lines, whereas their paired individual MRD cells are represented by black dots. Each patient-specific iPEP is represented using the automated population separator (APS1) plot based on a graphical representation of principal component 1 (x-axis) vs principal component 2 (y-axis) for a total of 25 parameters.