Interactome in primary MDS BM. (A) Heat map of number of pairwise expressed genes for interacting receptor-ligand pairs as quantified by CellPhoneDB. (B) Interaction of hematopoietic cells with MSCs and ECs quantified by number of expressed receptor-ligand pairs (bottom scale) and adhesiveness (top scale) in arbitrary units (AU) derived from RNAMagnet. (C) Exemplary quantitative expression of key receptor-ligand pairs for stromal-hematopoietic interaction for selected cell pairs. (D) Sankey plot for CXCL12 signaling from MSCs with various receptors to hematopoietic cells. Color-coded whether a specific ligand-receptor axis between cell populations is differentially active in MDS over HY. (E-F) Quantitative gene expression of CXCR4 and CD4 in myeloid progenitor cells in HY and MDS comparison, 2-sided Wilcox test derived from FindMarker function. (G) Quantification of CD4 expression in myeloid progenitor cells as gated by CD34⁺CD38⁺.