Summary:Currently, bone marrow (BM), cord blood (CB), and G-CSF-mobilized peripheral blood progenitor cells (PBPCs) are the most commonly used sources for allogeneic stem cell transplantation (SCT). The aim of this study was to assess the yields and distribution of lymphocyte subsets, lymphocyte progenitors and hematopoietic stem cells (HSC) in each type of allograft by threecolor flow cytometry. high T cells were highest in CB grafts (P р 0.001), and higher in LPs than in BM grafts (P р 0.02). The latter finding was in accordance with a preferential G-CSF mobilization of naive T cells relative to the total lymphocyte population (P р 0.014). CD3 + CD8 low and CD3 + CD8 low CD4 − subsets, which facilitate engraftment in murine transplantation models, demonstrated a tendency towards lower frequencies among T cells in CB grafts and LPs compared to BM grafts. This observation coincided with a significantly reduced mobilization of subsets potentially enriched for facilitating cells as compared to the total lymphocyte population (P р 0.036). The CD34 + compartment of CB grafts contained a significantly higher percentage (12.1%) of CD34 + CD7 + CD3 − T cell progenitors than those of BM grafts (5.1%) and LPs (3.6%). In addition, CB lymphocytes contained the highest fraction of CD3 − CD16/56

Background Pediatric hematology/oncology (PHO) patients receiving therapy or undergoing hematopoietic stem cell transplantation (HSCT) often require a central line and are at risk for bloodstream infections (BSI). There are limited data describing outcomes of BSI in PHO and HSCT patients. Methods This is a multicenter (n = 17) retrospective analysis of outcomes of patients who developed a BSI. Centers involved participated in a quality improvement collaborative referred to as the Childhood Cancer and Blood Disorder Network within the Children's Hospital Association. The main outcome measures were all‐cause mortality at 3, 10, and 30 days after positive culture date; transfer to the intensive care unit (ICU) within 48 hours of positive culture; and central line removal within seven days of the positive blood culture. Results Nine hundred fifty‐seven BSI were included in the analysis. Three hundred fifty‐four BSI (37%) were associated with at least one adverse outcome. All‐cause mortality was 1% (n = 9), 3% (n = 26), and 6% (n = 57) at 3, 10, and 30 days after BSI, respectively. In the 165 BSI (17%) associated with admission to the ICU, the median ICU stay was four days (IQR 2‐10). Twenty‐one percent of all infections (n = 203) were associated with central line removal within seven days of positive blood culture. Conclusions BSI in PHO and HSCT patients are associated with adverse outcomes. These data will assist in defining the impact of BSI in this population and demonstrate the need for quality improvement and research efforts to decrease them.

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