Marked expansion of lymphoid-primed progenitors in the bone marrow CD34⁺ cells of children with SCDs and thalassemia. (A) Dimensionality reduction using t-distributed stochastic neighbor embedding (t-SNE) on pooled data from 4 controls (n = 29 086), 3 thalassemia (n = 11 034), and 5 SCD patients (n = 11 776); cells identified distinct cell populations while preserving intercluster relationships. Cell type was annotated based on the expression of reported marker genes using AUcell (see supplemental Table 3). (B) Components of cell types identified in single-cell sequencing data: lymphoid progenitors (Lym_P), megakaryocyte/erythroid progenitors (M/E_P), granulocyte/monocyte progenitors (G/M_P), and HSPCs. (C) Quantification of B-progenitor cells by flow cytometry in healthy donors and patients (SCD in red and thalassemia in blue). (D) Multiparameter flow cytometry plots showing the expansion of CD10⁺CD19⁺ cells in CD34⁺ cells derived from the bone marrow of patients with SCD and thalassemia. AUC, area under the curve.