Development of gates to measure the immature platelet fraction in C57BL/6J mice using the Sysmex XN-V series multispecies hematology analyzer.

The immature platelet fraction (IPF) is a measure of newly released platelets, which has been used as a marker of platelet production in multiple human studies but is not widely available in multispecies analyzers. We developed gates to measure the IPF in diluted and undiluted murine blood samples on the Sysmex XN-1000V multispecies hematology analyzer. IPF gates were created using undiluted and diluted (1/10) blood samples obtained from adult and newborn (postnatal day 10, P10) C57BL/6J wild-type (WT) mice, and from 3 murine models of thrombocytopenia: c-MPL-/- mice, which lack the thrombopoietin receptor (hyporegenerative); antibody-mediated thrombocytopenia; and acute inflammation-induced thrombocytopenia. P10 mice were chosen because, at their size, we could consistently obtain (by terminal phlebotomy) the blood volume needed to run an undiluted sample. The undiluted blood IPF gate successfully differentiated between mechanisms of thrombocytopenia in both adult and P10 mice. For diluted samples, 2 IPF gates were generated: a thrombocytopenic (T) gate, which performed well in samples with platelet counts (PCs) <800 × 109/L in adult mice and <500 × 109/L in newborn mice, and a non-thrombocytopenic (NT) gate, which performed well in samples with PCs above these thresholds. PCs and IPFs measured in diluted blood using these gates agreed well with those measured in undiluted blood and had good reproducibility. These diluted gates allow for the accurate measurement of PCs and IPFs in small (10 µL) blood volumes, which can be obtained easily from adult and newborn mice as small as P1 to assess platelet production serially.

Adult Donor Blood Products as Risk Factors for Central Venous Catheter-associated Thromboembolism in Neonates: A Retrospective Case-Control Study.

This study aimed to examine whether the transfusion of donor blood products, abnormal coagulation or inflammation increase the risk of venous thromboembolism (VTE) associated with central venous catheters (CVC) in neonates. A retrospective case-control study including 25 neonates with CVC-associated VTE and tightly matched controls with CVC, but without VTE was performed. The frequency of (i) abnormal coagulation screens, (ii) increased inflammatory marker proteins before catheter insertion, or (iii) catheter-associated blood stream infection did not differ between cases and controls. No difference was found in the number or type of transfusions within the last day before VTE. However, the total number of transfusions in the time period between catheter placement and VTE diagnosis (median 6.5 d) was significantly higher (P<0.001) in cases (44 red blood cell, 61 plasma, and 18 platelet transfusions) compared with an equal median time period of 7 days postcatheter insertion in controls (26/24/11). In conclusion, intensive transfusion treatment (through a peripheral line) after CVC insertion was associated with a higher risk of VTE (odds ratio 7.58; 95% confidence interval, 0.84-68.46), suggesting that transfusion of adult donor blood products into the cellular and plasmatic hemostatic system of the neonate increases the risk for CVC-associated VTE.

Pooling, room temperature, and extended storage time increase the release of adult-specific biologic response modifiers in platelet concentrates: a hidden transfusion risk for neonates?

BACKGROUND: Adult donor platelets (PLTs) are frequently transfused to prevent or stop bleeding in neonates with thrombocytopenia. There is evidence for PLT transfusion-related morbidity and mortality, leading to the hypothesis on immunomodulatory effects of transfusing adult PLTs into neonates. Candidate factors are biologic response modifiers (BRMs) that are expressed at higher rates in adult than in neonatal PLTs. This study investigated whether storage conditions or preparation methods impact on the release of those differentially expressed BRMs. STUDY DESIGN AND METHODS: Pooled PLT concentrates (PCs) and apheresis PCs (APCs) were stored under agitation for up to 7 days at room temperature (RT) or at 2 to 8°C. The BRMs CCL5/RANTES, TGFß1, TSP1, and DKK1 were measured in PCs' supernatant, lysate, and corresponding plasma. PLT function was assessed by light transmission aggregometry. RESULTS: Concerning the preparation method, higher concentrations of DKK1 were found in pooled PCs compared to APCs. In supernatants, the concentrations of CCL5, TGFß1, TSP1, and DKK1 significantly increased, both over standard (≤4 days) and over extended storage times (7 days). Each of the four BRMs showed an up to twofold increase in concentration after storage at RT compared to cold storage (CS). There was no difference in the aggregation capacity. CONCLUSION: This analysis shows that the release of adult-specific BRMs during storage is lowest in short- and CS APCs. Our study points to strategies for reducing the exposure of sick neonates to BRMs that can be specifically associated to PLT transfusion-related morbidity.

The Erythropoietin Promoter Variant rs1617640 Is Not Associated with Severe Retinopathy of Prematurity, Independent of Treatment with Erythropoietin.

In this case-control study, the erythropoietin (EPO) promoter variant s1617640, linked to high intravitreal EPO concentrations and increased risk of diabetic retinopathy, was not associated with severe retinopathy of prematurity. This finding was observed both in infants with and without recombinant EPO administration.