Aberrant single-cell phenotype and clinical implications of genotypically defined polyclonal plasma cells in myeloma

Multiple Myeloma is driven by clonal plasma cell (cPC)-intrinsic factors and changes in the tumorigenic microenvironment (TME). To investigate if residual polyclonal PCs (pPCs) are disrupted, single-cell (sc) RNAseq and sc B-cell receptor analysis were applied in a cohort of 46 samples with PC dyscrasias and 21 healthy donors (HDs). Out of n=234,789 PCs, 64,432 were genotypically identified as pPCs with frequencies decreasing over different disease stages, from 23.66% in monoclonal gammopathy …