Transcriptional Heterogeneity and Lineage Commitment in Myeloid Progenitors The authors comprehensively mapped myeloid progenitor subpopulations by transcriptional sorting of single cells from bone marrow. They describe multiple progenitor subgroups, showing unexpected transcriptional priming toward seven differentiation fates but no progenitors with a mixed state. [Cell] Abstract | Graphical Abstract The Dlk1-Gtl2 Locus Preserves LT-HSC Function by Inhibiting the PI3K-mTOR Pathway to Restrict Mitochondrial Metabolism Investigators showed that the Dlk1-Gtl2 locus plays a critical role in preserving long-term repopulating hematopoietic stem cells (LT-HSCs). [Cell Stem Cell] Abstract | Graphical Abstract STAT5-Regulated microRNA-193b Controls Hematopoietic Stem and Progenitor Cell Expansion by Modulating Cytokine Receptor Signaling Researchers showed a regulatory circuit that prevents excessive hematopoietic stem cell self-renewal by upregulation of miR-193b upon self-renewal promoting thrombopoietin-MPL-STAT5 signaling. [Nat Commun] Full Article Microenvironmental Hypoxia Regulates FLT3 Expression and Biology in AML Investigators showed that 25% of acute myeloid leukemia patients (AML) down-regulate Fms-like tyrosine kinase 3 (FLT3) expression on blasts in response to in vitro hypoxia, which was independent of its mutational state. [Sci Rep] Full Article RNA-Based, Transient Modulation of Gene Expression in Human Hematopoietic Stem and Progenitor Cells The authors provide a broad-ranging comparison of transfection methods for hard-to-transfect cells and offer new opportunities for DNA-free, non-integrating gene modulation in hematopoietic stem and progenitor cells. [Sci Rep] Full Article Deoxycytidine Kinase Is Downregulated under Hypoxic Conditions and Confers Resistance against Cytarabine in Acute Myeloid Leukemia Researchers investigated the impact of hypoxic versus normoxic conditions on the sensitivity of acute myeloid leukemia (AML) cell lines and primary AML blasts to cytarabine. [Eur J Haematol] Abstract CLINICAL RESEARCH Novel Disease Burden Assessment Predicts Allogeneic Transplantation Outcomes in Myelodysplastic Syndrome Scientists analyzed hematopoietic cell transplantation outcomes by time of transplant disease variables, including blast percentage, percentage of cytogenetically abnormal cells and Revised International Prognostic Scoring System cytogenetic classification. [Bone Marrow Transplant] Abstract Impact of Conditioning with TBI in Adult Patients with T-Cell ALL Who Receive a Myeloablative Allogeneic Stem Cell Transplantation: A Report from the Acute Leukemia Working Party of EBMT With an overall follow-up of 58 months, 523 patients received a TBI-based regimen, whereas 78 patients received a chemotherapy-based regimen including IV busulfan–cyclophosphamide. Unlike patients >35 years, patients aged <35 years who received a TBI-based regimen displayed an improved outcome compared with patients who received a chemotherapy-based regimen [Bone Marrow Transplant] Abstract Ferritin as an Early Marker of Graft Rejection after Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Patients The authors analyzed ferritin plasma concentrations of 138 pediatric patients after hematopoietic stem cell transplantation. In 24 of the 27 pediatric patients with graft rejection, a significant increase of ferritin levels was observed 1 to 7 days prior to and at the time of graft rejection. [Ann Hematol] Abstract |