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Summary: The use of uncrewed aerial vehicles (drones) has increased over the last decade. However, their application in healthcare has not been fully examined, in part, due to regulations preventing flight beyond the visual line of sight. This prospective randomised controlled laboratory study aimed to determine whether the in vitro quality of packed red blood cell components is maintained when transported by drone, beyond visual line of sight. Ten identical pairs of packed red blood cell units were randomly allocated to transport by drone or by ground vehicle (1:1, allocation concealment) 68 km between two hospitals in Northumbria, UK. Markers of blood component quality were compared at 8, 14, 28 and 35 days following blood unit manufacture. There was no statistical difference in haemolysis, potassium concentration, total haemoglobin, glucose and lactate, haematocrit and mean cell volume, between the two groups, up to the date of unit expiry. The temperature of the packed red blood cell units did not deviate outside the recommended 2–10°C for transportation, regardless of the allocated group. Blood component transport was faster by drone, but did not reach statistical significance. This study demonstrates the feasibility and safety of flying blood components by drone between hospitals in the United Kingdom. [ABSTRACT FROM AUTHOR]

ABO blood group discrepancies in healthy individuals were caused by body‐wide chimerism and mosaicism. They can be evaluated with new diagnostic options for disease‐related cell clones that are typically associated with mosaicism. The observations raise the attention for sporadic mixed‐field observations of any blood group antigen. Commentary on: Dauber et al. Body‐wide chimerism and mosaicism are predominant causes of naturally occurring ABO discrepancies. Br J Haematol 2024; 205:1188‐1196 [ABSTRACT FROM AUTHOR]

The article discusses the use of predeposit autologous donation (PAD) in transfusion medicine. It highlights that PAD should only be used for patients with rare blood groups or multiple blood group antibodies where compatible allogeneic blood is difficult to obtain. The article also addresses recent concerns about the COVID-19 vaccination status of donors and emphasizes that PAD is not recommended for conscientious objections to donor blood. Preoperative autologous donation (PAD) is no longer recommended in obstetric practice due to the risks and potential complications involved. The article mentions various risks and concerns associated with PAD, such as errors in labeling and storage, donor anemia, wastage rates, and the need for fixed timings. It suggests alternative options like cell salvage and tranexamic acid. The guidelines recommend patient counseling, involvement of stakeholders, and adherence to blood regulations. Overall, PAD is rarely appropriate and should be carefully evaluated on a case-by-case basis. [Extracted from the article]

Summary: Optimal red cell transfusion support in myelodysplastic syndromes (MDS) has not been tested and established. The aim of this study was to demonstrate feasibility of recruitment and follow‐up in an outpatient setting with an exploratory assessment of quality of life (QoL) outcomes (EORTC QLQ‐C30 and EQ‐5D‐5L). We randomised MDS patients to standardised transfusion algorithms comparing current restrictive transfusion thresholds (80 g/l, to maintain haemoglobin 85–100 g/l) with liberal thresholds (105 g/l, maintaining 110–125 g/l). The primary outcomes were measures of compliance to transfusion thresholds. Altogether 38 patients were randomised (n = 20 restrictive; n = 18 liberal) from 12 participating sites in UK, Australia and New Zealand. The compliance proportion for the intention‐to‐treat population was 86% (95% confidence interval 75–94%) and 99% (95–100%) for restrictive and liberal arms respectively. Mean pre‐transfusion haemoglobin concentrations for restrictive and liberal arms were 80 g/l (SD6) and 97 g/l (SD7). The total number of red cell units transfused on study was 82 in the restrictive and 192 in the liberal arm. In an exploratory analysis, the five main QoL domains were improved for participants in the liberal compared to restrictive arm. Our findings support the feasibility and need for a definitive trial to evaluate the effect of different red cell transfusion thresholds on patient‐centred outcomes. [ABSTRACT FROM AUTHOR]

Keywords: Immunoglobulin; Paediatrics; Red cells EN Immunoglobulin Paediatrics Red cells 452 453 2 10/25/22 20221101 NES 221101 An international panel recently published guidelines for the use of intravenous immunoglobulin (IVIG) in immune-mediated haemolytic disease of the newborn (HDN).1 We suggest that their main recommendation, that ' I IVIG should not be routinely used to treat RhD- or ABO-antibody-mediated associated HDN i ' can be supported if referring only to early prophylactic dosing, but we disagree with their conclusion that recommendations cannot be made ' I for or against use of IVIG for neonates with rapidly rising bilirubin and emergent need for exchange transfusion (ET), as no studies have addressed this specific indication i '. If all such infants were to be included in a randomised controlled trial to study effects of IVIG to prevent ET, the statistical power of the trial would be considerably reduced. International guidelines regarding the role of intravenous immunoglobulin in the management of RhD- and ABO-mediated haemolytic disease of the newborn - reconsidering the recommendations. [Extracted from the article]

The article presents a study on lethal 5-amino-levulinate synthase gene (ALAS2) mutation in male X-linked sideroblastic anaemia (XLSA), which is reported in a four-generation pedigree. The syndrome was ascertained through an adult heterozygous female with skewed X inactivation, macrocytic congenital sideroblastic anaemia, and excessive number of miscarriages. The phenotype of XLSA in the female is explained.

Red blood cells ( RBCs) are generated from haematopoietic stem and progenitor cells ( HSPCs) through the step-wise process of differentiation known as erythropoiesis. In this review, we discuss our current understanding of erythropoiesis and highlight recent advances in this field. During embryonic development, erythropoiesis occurs in three distinct waves comprising first, the yolk sac-derived primitive RBCs, followed sequentially by the erythro-myeloid progenitor ( EMP) and HSPC-derived definitive RBCs. Recent work has highlighted the complexity and variability that may exist in the hierarchical arrangement of progenitors responsible for erythropoiesis. Using recently defined cell surface markers, it is now possible to enrich for erythroid progenitors and precursors to a much greater extent than has been possible before. While a great deal of knowledge has been gained on erythropoiesis from model organisms, our understanding of this process is currently being refined through human genetic studies. Genes mutated in erythroid disorders can now be identified more rapidly by the use of next-generation sequencing techniques. Genome-wide association studies on erythroid traits in healthy populations have also revealed new modulators of erythropoiesis. All of these recent developments have significant promise not only for increasing our understanding of erythropoiesis, but also for improving our ability to intervene when RBC production is perturbed in disease. [ABSTRACT FROM AUTHOR]

Ca2+-calmodulin (Ca2+-CaM) activates erythrocyte adenosine monophosphate deaminase (AMPD) in conditions of disturbed calcium homeostasis, prompting us to investigate adenine nucleotide metabolic dysregulation in sickle cell disease (SCD). However, higher ATP concentrations in reticulocytes, compared to erythrocytes, confound a comparative evaluation of SCD and normal RBCs. Therefore, a combination of centrifugation and antiCD71-labelled magnetic bead selection was used to prepare reticulocyte-poor fractions (reticulocytes <4% of total RBCs) of SCD RBCs. ATP and total adenine nucleotide concentrations were 12% lower in sickle erythrocytes compared to normal erythrocytes and inosine monophosphate (IMP) concentrations were threefold elevated (all P < 0·05). Furthermore, preincubation with a diffusible CaM antagonist slowed IMP accumulation in sickle erythrocytes during an experimental period of energy imbalance, thus showing that Ca2+-CaM activates AMPD in SCD. Finally, adenine treatment (100 μmol/l) of ex vivo SCD RBCs significantly expanded ATP levels (16% higher) and reduced phosphatidylserine (PS)-exposure, specifically those cells with the highest levels of PS externalization (46% fewer events) (both P-values <0·05 compared to untreated samples). We conclude that Ca2+-CaM activation of AMPD contributes to increased turnover of the adenine nucleotide pool in sickle erythrocytes and that this metabolic dysregulation promotes PS exposure that may contribute to the pathogenesis of SCD. [ABSTRACT FROM AUTHOR]

There is now convincing evidence that the extremely high frequencies of certain genetic disorders of the red cell involving haemoglobin, the red-cell membrane, or its metabolic pathways reflect relative resistance to malaria over thousands of years. At least some progress has been made towards an understanding of the cellular mechanisms involved, although much remains to be learnt. As well as the extremely valuable information that this field is providing about how exposure to infection has moulded the current structure of the human genome, recent research in this field is starting to provide some valuable new approaches to the better control of parasitic and other infections that remain a major global health problem. [ABSTRACT FROM AUTHOR]

Studies during the last three decades have enabled the development of detailed molecular insights into the structural basis of altered function in various inherited red cell membrane disorders. This review highlights our current understanding of molecular and mechanistic insights into various inherited red cell membrane disorders involving either altered membrane structural organization (hereditary spherocytosis, hereditary elliptocytosis and hereditary ovalocytosis) or altered membrane transport function (hereditary stomatocytosis). The molecular basis for the vast majority of cases of hereditary spherocytosis, elliptocytosis and ovalocytosis have been fully defined while little progress has been made in defining the molecular basis for hereditary stomatocytosis. Mutations in a number of distinct genes account for hereditary spherocytosis and elliptocytosis, while a single genetic defect accounts for all cases of hereditary ovalocytosis. Based on these molecular insights, a comprehensive understanding of the structural basis for altered membrane function has been developed. Loss of vertical linkage between membrane skeleton and lipid bilayer leads to membrane loss in hereditary spherocytosis, while weakening of lateral linkages between skeletal proteins leads to membrane fragmentation and surface area loss in hereditary elliptocytosis. Importantly, the severity of anaemia in both these disorders is directly related to extent of membrane surface area loss. Splenectomy results in amelioration of anaemia. [ABSTRACT FROM AUTHOR]

We have developed an assay of thrombin generation in clotting whole blood. Because our goal was to study patients with red blood cell diseases that are associated with thrombosis, the initial evaluation of this assay analysed the effect of the haematocrit and haemolysate on the total amount of thrombin activity generated and the maximal concentration of thrombin achieved. Both of these parameters were proportional to the haematocrit throughout a wide range of clinically relevant cell concentrations. Red cell lysate also augmented thrombin generation. Because this effect was removed by filtration of the lysate, we propose that it was related to red cell microparticles. [ABSTRACT FROM AUTHOR]

Lutheran (Lu) and Lu(v13), two glycoprotein (gp) isoforms belonging to the immunoglobulin superfamily, represent adhesion molecules that act as erythrocyte receptors for laminin 10/11. These two gps, which differ only by the length of their cytoplasmic tail, carry both Lu blood group and Basal Cell Adhesion Molecule (B-CAM) antigens. Here, analysis of the Triton extractability of recombinant Lu and Lu(v13) gps in K562 transfected cells showed that both gps were mainly associated with the detergent-insoluble material. Patching experiments using Cholera Toxin subunit B indicated that Lu gps were not localized in lipid rafts. Glutathione- S-transferase capture assays showed that the cytoplasmic domain of Lu and Lu(v13) bound to erythroid spectrin, present in a low ionic strength extract from red cell ghosts. Direct interaction with spectrin was confirmed by plasmon resonance assays. Site-directed mutagenesis mapped a major interaction site with spectrin to the RK573-574 motif, located on the cytoplasmic tail of Lu gp, in close vicinity to the inner leaflet of the membrane lipid bilayer. The two Lu adhesion gps represent the first example of a direct link between transmembrane proteins and spectrin in red blood cells. Since Lu gps are low abundant proteins, we speculate that their interaction with spectrin might be critical for signalling and receptor function rather than for participating in the linkage of the lipid bilayer to the red cell skeleton. [ABSTRACT FROM AUTHOR]

Profiles hematologist Maxwell Wintrobe. Education and training; Career highlights; Contributions to the field of hematology.

The time course expression of blood group antigens was examined by flow cytometry using a two-phase liquid culture system that supports the proliferation and maturation of human erythroid progenitors from adult peripheral blood. The progression towards erythroid differentiation was followed by the expression changes of the transferrin receptor (CD71++) and glycophorin A (GPA+). Four main categories of blood group markers were identified: (i) those characterized by an early expression like ABO (A), Kell (K:2) and Rh50 which were detected in the Epo-independent phase 1, (ii) those including GPC (Gerbich, Ge antigens) and Fy6 which were expressed in the late phase 1, (iii) GPA (MN antigens), Wrb (Band 3/GPA interaction), Rh(D, Cc/Ee) and LW which appeared during the Epo-dependent phase 2 and (iv) those like Jk3 and Lub which were expressed in late phase 2. Regarding blood group molecules exhibiting adhesive properties (LW/ICAM-4, Oka and Lu) the most significant event was a sharp decrease of Oka (neurothelin) expression with the concomitant loss of ICAMs expression during the later stage of differentiation. These studies suggest that Oka, ICAMs and LW might contribute to the adhesive interactions involved in the formation of erythroblastic islands and attachment to stroma cells and the extracellular matrix. We also noted an asynchronous expression of the proteins that compose the core of the Rh complex, since Rh50 glycoprotein was expressed earlier than Rh(D, CE) proteins. [ABSTRACT FROM AUTHOR]

Various techniques have been used to assess the flow properties of blood and blood cells in a range of clinical situations. Filtration through microfilters offers a single technique for measuring the flow properties of all cellular components of blood in one experiment but depends on an assumed ability to recognize cells that make up <10% of leucocytes. The remaining leucocytes, labelled fast leucocytes, were previously presumed to be lymphocytes and granulocytes. This study confirmed the identities of these fast leucocytes as those of lymphocytes and granulocytes in undiluted blood. The transit time for lymphocytes (1.2 s) and granulocytes (1.6 s) is close to that recorded for fast leucocytes (1.7 s). The resistance of each type of blood cell to flow through 5 μm filters was defined in this study as the product of the concentration of that cell in blood and its transit time through a pore in the filter. The total resistance to flow of healthy blood through the filter is 4.46 × 107 s/ml and is attributed to plasma (2.7%), red cells (25.9%), fast leucocytes (25.3%) and slow leucocytes (46.1%). In a cohort of 21 men with peripheral arterial disease the total resistance was increased to 7.82 × 107 s/ml and attributed to plasma (1.5%), red cells (14.5%), fast leucocytes (21.0%) and slow leucocytes (63.0%). This analysis therefore provides a single test for assessing the flow properties of all the cellular components of blood and plasma. [ABSTRACT FROM AUTHOR]

The article reports that erythrocytes infected by plasmodium falciparum induce hepcidin (HAMP) mRNA synthesis by peripheral blood mononuclear cells. Leucocyte's response to parasitized cells give a source for hepcidin during malaria, similar to hepcidin synthesis by leucocytes after exposure to bacterial lipopolysaccharride (LPS). As new red cells are not produced to replace those lost by haemolysis and ingestion by macrophages, the suppressed erythropoiesis contributes to malarial anaemia.