Fig. 5: BM stromal composition differs between YP and AYA BM.

a–c, Xenium spatial transcriptomics-based UMAP of 163,325 cells from BM trephine biopsies of YP (n = 3, age 0.7–1.5 years, two male and one female donor) and AYA donors (n = 3, age 13.5–23 years, all male donors; Supplementary Table 7), showing the identification of 27 clusters, annotated and grouped into 11 major populations: HSPC (3 subsets), B and plasma cells (5 subsets), T and NK cells (3 subsets), myeloid populations (5 subsets), stromal cells (5 subsets), erythroid cells, dendritic cells, megakaryocytes, erythroid cells, sinusoidal endothelial cells and arteriolar endothelial cell or vascular smooth muscle cells, annotated per major population (a) and subcluster (b). c, UMAP of cells as in a showing adipo-MSC (n = 3,571 cells), adipocytes (n = 478 cells), fibro-MSC (n = 38 cells), fibro/osteo-MSC (n = 598 cells), osteo-MSC (n = 265 cells) and osteoclasts (n = 82 cells). Key markers for each subpopulation are available in Supplementary Table 2. d, Representative BM cores from each individual as in a showing the spatial distribution of adipo-MSC, adipocytes, fibro-MSC, fibro/osteo-MSC, osteo-MSC and osteoclasts; scale bar, 300 μm. e, Stacked bar plot showing the relative abundance of adipo-MSC, adipocytes, fibro-MSC, fibro/osteo-MSC, osteo-MSC and osteoclasts in each individual. Osteo-MSC (YP BM median 12.2% of total MSC; AYA BM median of 1.4% of total MSC, mixed-effects logistic regression with donor as random intercept, Benjamini–Hochberg-adjusted P = 3.2 × 10⁻¹⁶), adipocytes (YP BM median 2.0% of total MSC; AYA BM median 14.0% of total MSC; Benjamini–Hochberg-adjusted P = 2.3 × 10⁻³⁶) and adipo-MSC (YP BM median 73.6% of total MSC; AYA BM median 66.1% of total MSC; Benjamini–Hochberg-adjusted P = 0.60).