Fig. 1: Transcriptional and functional heterogeneity of BMPC.

a Bone marrow plasma cells (BMPC; CD138^high CD38^high or CD38^high CD27^high) from 8 patients undergoing total hip replacement surgery were isolated and sorted by FACS for single-cell sequencing (gating strategy in Supplementary Fig. 1a). Amplified area: UMAP representation of remaining 38235 plasma cells after exclusion of contaminant and poor quality cells (see Supplementary Fig. 1b). Clusters of transcriptionally similar cells were identified using shared nearest neighbour (SNN) modularity optimisation. b Percentage of BMPC found in each cluster per donor’s total cells analysed. Horizontal lines indicate the median. n = 8 independent donors. c UMAP representation of the expression levels of selected PC signature genes across BMPC clusters. d Bubble plots of expression levels of the top five marker genes for each cluster (left) and of additional selected genes (right). Colour scale shows the z scores of the average expression of a gene within the indicated cluster. Bubble sizes correspond to the fraction of cells expressing a defined gene within the indicated cluster. e Density plots of immunoglobulin isotype expression within the BMPC compartment. f Frequency of plasma cells expressing a defined immunoglobulin isotype, displayed according to the clusters in a, per donor’s total cells where a full BCR could be identified. For better readability, each isotype was plotted separately, even though the percentages are related to the total BCRs from each donor. Horizontal lines indicate the median. n = 8 independent donors. g Density plots of BMPC significantly enriched in gene sets from different biological pathways as calculated by Gene Set Enrichment Analysis (GSEA). Source data are provided as a Source Data file.