A Combined Immunophenotypic And Transcriptional Single-Cell Map Of First Trimester Human Fetal Liver Hematopoiesis

Knowledge of human fetal blood development and how it differs from adult is highly relevant for our understanding of congenital blood and immune disorders as well as childhood leukemia, the latter known to originate in utero. Blood production during development occurs in waves that overlap in time and space adding to heterogeneity, which necessitates single cell approaches. Here, a combined single cell immunophenotypic and transcriptional map of first trimester primitive blood development is presented. Using CITE-seq (Cellular Indexing of Transcriptomes and Epitopes by Sequencing) the molecular profile of established immunophenotypic gated progenitors was analyzed in the fetal liver (FL). Classical markers for hematopoietic stem cells (HSCs) such as CD90 and CD49F were largely preserved, whereas CD135 (FLT3) and CD123 (IL3R) had a ubiquitous expression pattern capturing heterogenous populations. Direct molecular comparison with an adult bone marrow (BM) data set revealed that HSC-like cells were less frequent in FL, whereas cells with a lympho-myeloid signature were more abundant. Furthermore, an erythro-myeloid primed multipotent progenitor cluster was identified, potentially representing a transient, FL-specific progenitor. Based on the projection performed, up- and downregulated genes between fetal and adult cells were analyzed. In general, cell cycle pathways, including MYC targets were shown to be upregulated in fetal cells, whereas gene sets involved in inflammation and human leukocyte antigen (HLA) complex were downregulated. Importantly, a fetal core molecular signature was identified that could discriminate certain types of infant and childhood leukemia from adult counterparts. Our detailed single cell map presented herein emphasizes molecular as well as immunophenotypic differences between fetal and adult primitive blood cells, of significance for future studies of pediatric leukemia and blood development in general.

The Effects of Ketamin-Midazolam and Ketamin-Propofol on Bispectral Index Score as Sedatives During Bone Marrow Puncture Procedure Among Pediatrics

Background: Bone Marrow Puncture (BMP) is an invasive procedure associated with pain and anxiety. The ketamine-midazolam and the ketamine-propofol is an effectivecombination with minimal side effects. This study of the study aims to compare the effect of the combination of ketamine-midazolam and ketamine- propofol on sedation depth based on BIS in pediatric leukemia patients undergoing BMP. Methods: This study was a randomized controlled trial that was done single-blinded. The population was all pediatric patients diagnosed with leukemia who underwent BMP at RSMH and performed sedation. The research sample is the population that fulfill the inclusion and exclusion criteria. The sample size for each group was 25, with 50 Subjects in total. Sampling was done by block randomization. Results: This study found no differences in sex, age, and body weight between the two groups ([p=1.000], [p=0.845], and [p=0.147], respectively). In this study, there was no difference in mean MAP (p=0.592), oxygen saturation (p=0.164), heart rate (p=0.098), and respiratory rate (p=0.252) before intervention between the two groups. BIS value of the two groups had significant difference before and after the intervention where the two groups could reduce BIS to reach the optimal value of sedation <60 (p <0.05) There was no difference in BIS before intervention in the two groups (p=0.385). In this study, it was found that hypersalivation occurred more frequently in the ketamine-midazolam combination group. Conclusion: The combination of ketamine-midazolam and ketamine-propofol was equally good for sedation as indicated by a decrease in the mean BIS in patients undergoing BMP.

Hi-C detects genomic structural variants in peripheral blood of pediatric leukemia patients

B-cell acute lymphoblastic leukemia (B-ALL) is often driven by chromosome translocations that result in recurrent and well-studied gene fusions. Currently, fluorescent in-situ hybridization probes are employed to detect candidate translocations in bone marrow samples from B-ALL patients. Recently Hi-C, a sequencing-based technique originally designed to reconstruct the three-dimensional architecture of the nuclear genome, was shown to effectively recognize structural variants. Here, we demonstrate that Hi-C can be used as a genome-wide assay to detect translocations and other structural variants of potential clinical interest. Structural variants were identified in both bone marrow and peripheral blood samples, including an ETV6-RUNX1 translocation present in one pediatric B-ALL patient. Our report provides proof-of-principle that Hi-C could be an effective strategy to globally detect driver structural variants in B-ALL peripheral blood specimens, reducing the need for invasive bone marrow biopsies and candidate-based clinical tests.

Clofarabine-fludarabine-busulfan in HCT for pediatric leukemia: an effective, low toxicity, TBI-free conditioning regimen

We prospectively studied CloFluBu-conditioning in allogeneic Hematopoietic Cell Therapy (HCT) for lymphoid- and myeloid malignancies, and hypothesized that CloFluBu provides a less toxic alternative to conventional conditioning regimens, with adequate anti-leukemic activity. All patients receiving their first HCT, from 2011-2019, were included and received CloFluBu. Primary endpoint was Event Free Survival (EFS). Secondary endpoints were Overall Survival (OS), Graft-versus-Host-Disease (GvHD)-Relapse-Free Survival (GRFS), Treatment Related Mortality (TRM), Cumulative Incidence of Relapse (CIR), acute and chronic GvHD, and veno-occlusive disease (VOD). Cox Proportional Hazard- and Fine and Gray competing-risk models were used for data analysis. 155 Children were included; 60 acute lymphoid leukemia (ALL), 69 acute myeloid leukemia (AML), and 26 other malignancies (mostly MDS-EB). Median age was 9.7 (0.5-18.6) years. Estimated 2-yr EFS was 72.0% ± 6.0 in ALL, and 62.4% ± 6.0 in AML patients. TRM in the whole cohort was 11.0% ± 2.6, incidence of aGvHD III-IV at 6 months was 12.3% ± 2.7, extensive chronic GvHD at 2-yr was 6.4% ± 2.1. Minimal residual disease-positivity prior to HCT was associated with higher CIR, both in ALL and AML. CloFluBu showed limited toxicity and encouraging EFS. CloFluBu is a potentially less toxic alternative to conventional conditioning regimens. Randomized prospective studies are needed.

Single-Cell Sequencing: Biological Insight and Potential Clinical Implications in Pediatric Leukemia

Single-cell sequencing (SCS) provides high-resolution insight into the genomic, epigenomic, and transcriptomic landscape of oncohematological malignancies including pediatric leukemia, the most common type of childhood cancer. Besides broadening our biological understanding of cellular heterogeneity, sub-clonal architecture, and regulatory network of tumor cell populations, SCS can offer clinically relevant, detailed characterization of distinct compartments affected by leukemia and identify therapeutically exploitable vulnerabilities. In this review, we provide an overview of SCS studies focused on the high-resolution genomic and transcriptomic scrutiny of pediatric leukemia. Our aim is to investigate and summarize how different layers of single-cell omics approaches can expectedly support clinical decision making in the future. Although the clinical management of pediatric leukemia underwent a spectacular improvement during the past decades, resistant disease is a major cause of therapy failure. Currently, only a small proportion of childhood leukemia patients benefit from genomics-driven therapy, as 15–20% of them meet the indication criteria of on-label targeted agents, and their overall response rate falls in a relatively wide range (40–85%). The in-depth scrutiny of various cell populations influencing the development, progression, and treatment resistance of different disease subtypes can potentially uncover a wider range of driver mechanisms for innovative therapeutic interventions.