Fetal/neonatal alloimmune thrombocytopenia: a systematic review of impact of HLA-DRB3*01:01 on fetal/neonatal outcome.

The most common, severe cases of fetal and neonatal alloimmune thrombocytopenia among whites are caused by antibodies against human platelet antigen 1a (HPA-1a). The aims of this systematic review and meta-analysis are to determine the association between maternal HLA-DRB3*01:01 and: (1) HPA-1a-alloimmunization and (2) neonatal outcome in children born of HPA-1a-immunized women. A systematic literature search identified 4 prospective and 8 retrospective studies. Data were combined across studies to estimate pooled odds ratios (ORs) and the associated 95% confidence intervals (CIs). The population represented by the prospective studies was more than 150 000. In the prospective studies, there were 64 severely thrombocytopenic newborns (platelet count <50 × 109/L) of whom 3 had intracranial hemorrhage. The mothers of all 64 children were HLA-DRB3*01:01+. The number of severely thrombocytopenic children born of HPA-1a-alloimmunized women in the retrospective studies was 214; 205 of whom were born of HLA-DRB3*01:01+ women. For HLA-DRB3*01:01- women, the OR (95% CI) for alloimmunization was 0.05 (0.00-0.60), and for severe neonatal thrombocytopenia 0.08 (0.02-0.37). This meta-analysis demonstrates that the risk of alloimmunization and of having a child with severe thrombocytopenia are both very low for HPA-1a- women who are HLA-DRB3*01:01-.

Effects of the COVID-19 pandemic on supply and use of blood for transfusion.

The COVID-19 pandemic has major implications for blood transfusion. There are uncertain patterns of demand, and transfusion institutions need to plan for reductions in donations and loss of crucial staff because of sickness and public health restrictions. We systematically searched for relevant studies addressing the transfusion chain-from donor, through collection and processing, to patients-to provide a synthesis of the published literature and guidance during times of potential or actual shortage. A reduction in donor numbers has largely been matched by reductions in demand for transfusion. Contingency planning includes prioritisation policies for patients in the event of predicted shortage. A range of strategies maintain ongoing equitable access to blood for transfusion during the pandemic, in addition to providing new therapies such as convalescent plasma. Sharing experience and developing expert consensus on the basis of evolving publications will help transfusion services and hospitals in countries at different stages in the pandemic.

Position paper on International Collaboration for Transfusion Medicine (ICTM) Guideline 'Red blood cell specifications for patients with hemoglobinopathies: a systematic review and guideline'.

The International Collaboration for Transfusion Medicine Guidelines (ICTMG) has published guidance on transfusion for haemoglobinopathies. To give a UK perspective on this guidance, each of the recommendations in the ICTMG guideline were reviewed and the applicability for transfusion practice in the UK considered with reference to relevant published British Society for Haematology (BSH) guidelines and national standards . There was much consensus; however, there was disparity surrounding the recommendations for routinely extended matching in those with alloimmunisation.

Postnatal intervention for the treatment of FNAIT: a systematic review.

OBJECTIVE: Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is associated with life-threatening bleeding. This systematic review of postnatal management of FNAIT examined transfusion of human platelet antigen (HPA) selected or unselected platelets, and/or IVIg on platelet increments, hemorrhage and mortality. STUDY DESIGN: MEDLINE, EMBASE and Cochrane searches were conducted until 11 May 2018. RESULT: Of 754 neonates, 382 received platelet transfusions (51%). HPA-selected platelets resulted in higher platelet increments and longer response times than HPA-unselected platelets. However, unselected platelets generally led to sufficient platelet increments to 30 × 109/L, a level above which intracranial hemorrhage or other life-threatening bleeding rarely occurred. Platelet increments were not improved with the addition of IVIg to platelet transfusion. CONCLUSION: Overall, HPA-selected platelet transfusions were more effective than HPA-unselected platelets but unselected platelets were often effective enough to achieve clinical goals. Available studies do not clearly demonstrate a benefit for addition of IVIg to platelet transfusion.

Fetal and neonatal alloimmune thrombocytopenia: recommendations for evidence-based practice, an international approach.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) may result in severe bleeding, particularly fetal and neonatal intracranial haemorrhage (ICH). As a result, FNAIT requires prompt identification and treatment; subsequent pregnancies need close surveillance and management. An international panel convened to develop evidence-based recommendations for diagnosis and management of FNAIT. A rigorous approach was used to search, review and develop recommendations from published data for: antenatal management, postnatal management, diagnostic testing and universal screening. To confirm FNAIT, fetal human platelet antigen (HPA) typing, using non-invasive methods if quality-assured, should be performed during pregnancy when the father is unknown, unavailable for testing or heterozygous for the implicated antigen. Women with a previous child with an ICH related to FNAIT should be offered intravenous immunoglobulin (IVIG) infusions during subsequent affected pregnancies as early as 12 weeks gestation. Ideally, HPA-selected platelets should be available at delivery for potentially affected infants and used to increase the neonatal platelet count as needed. If HPA-selected platelets are not immediately available, unselected platelets should be transfused. FNAIT studies that optimize antenatal and postnatal management, develop risk stratification algorithms to guide management and standardize laboratory testing to identify high risk pregnancies are needed.

The burden of invasive infections in neutropenic patients: incidence, outcomes, and use of granulocyte transfusions.

BACKGROUND: Patients with prolonged neutropenia caused by chemotherapy or underlying marrow disorders are at risk of invasive bacterial and fungal infections. New treatment options alongside targeted antimicrobial therapy that might improve outcomes include granulocyte transfusions (GTX). To inform the research agenda, a prospective observational cohort study was performed in the Netherlands and United Kingdom. The aim was to describe the incidence, characteristics, and outcomes of patients developing invasive infections and assess patients fulfilling criteria for GTX. STUDY DESIGN AND METHODS: All patients receiving myeloablative chemotherapy and anticipated to develop 7 or more days of neutropenia (<0.5 × 109 /L) were eligible and followed for the development of invasive infections according to a defined algorithm and mortality up to 100 days. Secondary outcomes were types of infection and eligibility for GTX. RESULTS: A total of 471 patients enrolled at six hematology-oncology departments were followed for 569 neutropenic episodes. Overall, 32.5% of patients developed invasive infections during their first episode. Significant baseline risk factors for developing infections were high comorbidity scores (WHO performance status ≥ 2, hazard ratio [HR], 2.6 [1.7-3.9]; and hematopoietic cell transplantation-comorbidity index score ≥ 2 HR 1.3 [0.9-1.8]). Infections were bacterial (59.4%) and fungal (22.3%). Despite 34 patients (6.3% of all episodes) appearing to meet criteria to receive GTX, only nine patients received granulocytes. The HR for death was 5.8 (2.5-13.0) for patients with invasive infections. CONCLUSION: This study documents that invasive infections are associated with significant mortality. There is a need for new strategies to prevent and treat infections, which may include better understanding of use GTX.

Maternal HPA-1a antibody level and its role in predicting the severity of Fetal/Neonatal Alloimmune Thrombocytopenia: a systematic review.

BACKGROUND AND OBJECTIVES: In Caucasians, fetal/neonatal alloimmune thrombocytopenia (FNAIT) is most commonly due to maternal HPA-1a antibodies. HPA-1a typing followed by screening for anti-HPA-1a antibodies in HPA-1bb women may identify first pregnancies at risk. Our goal was to review results from previous published studies to examine whether the maternal antibody level to HPA-1a could be used to identify high-risk pregnancies. MATERIALS AND METHODS: The studies included were categorized by recruitment strategies: screening of unselected pregnancies or samples analyzed from known or suspected FNAIT patients. RESULTS: Three prospective studies reported results from screening programmes, and 10 retrospective studies focused on suspected cases of FNAIT. In 8 studies samples for antibody measurement, performed by the monoclonal antibody immobilization of platelet antigen (MAIPA) assay, and samples for determining fetal/neonatal platelet count were collected simultaneously. In these 8 studies, the maternal antibody level correlated with the risk of severe thrombocytopenia. The prospective studies reported high negative predictive values (88-95%), which would allow for the use of maternal anti-HPA-1a antibody level as a predictive tool in a screening setting, in order to identify cases at low risk for FNAIT. However, due to low positive predictive values reported in prospective as well as retrospective studies (54-97%), the maternal antibody level is less suited for the final diagnosis and for guiding antenatal treatment. CONCLUSION: HPA-1a antibody level has the potential to predict the severity of FNAIT.

Antenatal management in fetal and neonatal alloimmune thrombocytopenia: a systematic review.

Several strategies can be used to manage fetal or neonatal alloimmune thrombocytopenia (FNAIT) in subsequent pregnancies. Serial fetal blood sampling (FBS) and intrauterine platelet transfusions (IUPT), as well as weekly maternal IV immunoglobulin infusion (IVIG), with or without additional corticosteroid therapy, are common options, but optimal management has not been determined. The aim of this systematic review was to assess antenatal treatment strategies for FNAIT. Four randomized controlled trials and 22 nonrandomized studies were included. Pooling of results was not possible due to considerable heterogeneity. Most studies found comparable outcomes regarding the occurrence of intracranial hemorrhage, regardless of the antenatal management strategy applied; FBS, IUPT, or IVIG with or without corticosteroids. There is no consistent evidence for the value of adding steroids to IVIG. FBS or IUPT resulted in a relatively high complication rate (consisting mainly of preterm emergency cesarean section) of 11% per treated pregnancy in all studies combined. Overall, noninvasive management in pregnant mothers who have had a previous neonate with FNAIT is effective without the relatively high rate of adverse outcomes seen with invasive strategies. This systematic review suggests that first-line antenatal management in FNAIT is weekly IVIG administration, with or without the addition of corticosteroids.

The ins and outs of reticulocyte maturation revisited: The role of autophagy in sickle cell disease.

Autophagy plays an important role in the removal of membrane bound organelles during the last stage of erythropoiesis as the enucleate reticulocyte matures into the erythrocyte. Autophagic vesicles are expelled from the reticulocyte as intact, inside-out, phosphatidylserine (PS) decorated vesicles and are subsequently removed during splenic passage. Failure to remove these vesicles causes the elevation in PS exposed red cells in Sickle Cell Disease.

Granulocyte transfusions for treating infections in people with neutropenia or neutrophil dysfunction.

BACKGROUND: Despite modern antimicrobials and supportive therapy bacterial and fungal infections are still major complications in people with prolonged disease-related or treatment-related neutropenia. Transfusions of granulocytes have a long history of usage in clinical practice to support and treat severe infection in high-risk groups of patients with neutropenia or neutrophil dysfunction. However, there is considerable current variability in therapeutic granulocyte transfusion practice, and uncertainty about the beneficial effect of transfusions given as an adjunct to antibiotics on mortality. This is an update of a Cochrane review first published in 2005. OBJECTIVES: To determine the effectiveness and safety of granulocyte transfusions compared to no granulocyte transfusions as adjuncts to antimicrobials for treating infections in people with neutropenia or disorders of neutrophil function aimed at reducing mortality and other adverse outcomes related to infection. SEARCH METHODS: We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 2). MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1980) and ongoing trial databases to 11 February 2016. SELECTION CRITERIA: RCTs comparing people with neutropenia or disorders of neutrophil dysfunction receiving granulocyte transfusions to treat infection with a control group receiving no granulocyte transfusions. Neonates are the subject of another Cochrane review and were excluded from this review. There was no restriction by outcomes examined, language or publication status. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by the Cochrane Collaboration. MAIN RESULTS: We identified 10 trials that met the inclusion criteria with a total of 587 participants. We also identified another ongoing trial. These trials were conducted between 1975 and 2015. None of the studies included people with neutrophil dysfunction. The studies differed in the type of infections they included. Six studies included both children and adults, however data were not reported separately for children and adults. The two newest studies gave granulocyte colony stimulating factor (G-CSF) to donors; both were stopped early due to lack of recruitment. Three studies re-randomised participants and therefore quantitative analysis was unable to be performed.Overall the quality of the evidence was very low to low across different outcomes according to GRADE methodology. This was due to many of the studies being at high risk of bias, and many of the outcomes being imprecise.There may be no difference in all-cause mortality over 30 days between participants receiving therapeutic granulocyte transfusions and those that did not (six studies; 321 participants; RR 0.75, 95% CI 0.54 to 1.04; very low-quality evidence). There were no differences between the granulocyte dose subgroups (< 1 x 10(10) per day versus ≥ 1 x 10(10) per day) (test for subgroup differences P = 0.39). There was a difference in all-cause mortality between the studies based on the age of the study (published before 2000 versus published 2000 or later) (test for subgroup differences P = 0.03). There was no difference in all-cause mortality between participants receiving granulocyte transfusions and those that did not in the newest study (one study; 111 participants; RR 1.10, 95% CI 0.70 to 1.73, low-quality evidence). There may be a reduction in all-cause mortality in participants receiving granulocyte transfusions compared to those that did not in studies published before the year 2000 (five studies; 210 participants; RR 0.53, 95% CI 0.33 to 0.85; low-quality evidence).There may be no difference in clinical reversal of concurrent infection between participants receiving therapeutic granulocyte transfusions and those that did not (five studies; 286 participants; RR 0.98, 95% CI 0.81 to 1.19; low-quality evidence).There is insufficient evidence to determine whether there is a difference in pulmonary serious adverse events (1 study; 24 participants; RR 0.85, 95% CI 0.38 to 1.88; very low-quality evidence).None of the studies reported number of days on therapeutic antibiotics, number of adverse events requiring discontinuation of treatment, or quality of life.Six studies reported their funding sources and all were funded by governments or charities. AUTHORS' CONCLUSIONS: In people who are neutropenic due to myelosuppressive chemotherapy or a haematopoietic stem cell transplant, there is insufficient evidence to determine whether granulocyte transfusions affect all-cause mortality. To be able to detect a decrease in all-cause mortality from 35% to 30% would require a study containing at least 2748 participants (80% power, 5% significance). There is low-grade evidence that therapeutic granulocyte transfusions may not increase the number of participants with clinical resolution of an infection.

Autophagic vesicles on mature human reticulocytes explain phosphatidylserine-positive red cells in sickle cell disease.

During maturation to an erythrocyte, a reticulocyte must eliminate any residual organelles and reduce its surface area and volume. Here we show this involves a novel process whereby large, intact, inside-out phosphatidylserine (PS)-exposed autophagic vesicles are extruded. Cell surface PS is a well-characterized apoptotic signal initiating phagocytosis. In peripheral blood from patients after splenectomy or in patients with sickle cell disease (SCD), the number of circulating red cells exposing PS on their surface is elevated. We show that in these patients PS is present on the cell surface of red cells in large (∼1.4 µm) discrete areas corresponding to autophagic vesicles. The autophagic vesicles found on reticulocytes are identical to those observed on red cells from splenectomized individuals and patients with SCD. Our data suggest the increased thrombotic risk associated with splenectomy, and patients with hemoglobinopathies is a possible consequence of increased levels of circulating mature reticulocytes expressing inside-out PS-exposed autophagic vesicles because of asplenia.

Granulocyte transfusions for preventing infections in people with neutropenia or neutrophil dysfunction.

BACKGROUND: Despite modern antimicrobials and supportive therapy, bacterial and fungal infections are still major complications in people with prolonged disease-related or therapy-related neutropenia. Since the late 1990s there has been increasing demand for donated granulocyte transfusions to treat or prevent severe infections in people who lack their own functional granulocytes. This is an update of a Cochrane review first published in 2009. OBJECTIVES: To determine the effectiveness and safety of prophylactic granulocyte transfusions compared with a control population not receiving this intervention for preventing all-cause mortality, mortality due to infection, and evidence of infection due to infection or due to any other cause in people with neutropenia or disorders of neutrophil function. SEARCH METHODS: We searched for randomised controlled trials (RCTs) and quasi-RCTs in the Cochrane Central Register of Controlled Trials (Cochrane Library 2015, Issue 3), MEDLINE (from 1946), EMBASE (from 1974), CINAHL (from 1937), theTransfusion Evidence Library (from 1980) and ongoing trial databases to April 20 2015. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-RCTs comparing people receiving granulocyte transfusions to prevent the development of infection with a control group receiving no granulocyte transfusions. Neonates are the subject of another Cochrane review and were excluded from this review. There was no restriction by outcomes examined, but this review focuses on mortality, mortality due to infection and adverse events. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by The Cochrane Collaboration. MAIN RESULTS: Twelve trials met the inclusion criteria. One trial is still ongoing, leaving a total of 11 trials eligible involving 653 participants. These trials were conducted between 1978 and 2006 and enrolled participants from fairly comparable patient populations. None of the studies included people with neutrophil dysfunction. Ten studies included only adults, and two studies included children and adults. Ten of these studies contained separate data for each arm and were able to be critically appraised. One study re-randomised people and therefore quantitative analysis was unable to be performed.Overall, the quality of the evidence was very low to low across different outcomes according to GRADE methodology. This was due to many of the studies being at high risk of bias, and many of the outcome estimates being imprecise.All-cause mortality was reported for nine studies (609 participants). There was no difference in all-cause mortality over 30 days between people receiving prophylactic granulocyte transfusions and those that did not (seven studies; 437 participants; RR 0.92, 95% CI 0.63 to 1.36, very low-quality evidence).Mortality due to infection was reported for seven studies (398 participants). There was no difference in mortality due to infection over 30 days between people receiving prophylactic granulocyte transfusions and those that did not (six studies; 286 participants; RR 0.69, 95% CI 0.33 to 1.44, very low-quality evidence).The number of people with localised or systemic bacterial or fungal infections was reported for nine studies (609 participants). There were differences between the granulocyte dose subgroups (test for subgroup differences P = 0.01). There was no difference in the number of people with infections over 30 days between people receiving prophylactic granulocyte transfusions and those that did not in the low-dose granulocyte group (< 1.0 x 10(10) granulocytes per day) (four studies, 204 participants; RR 0.84, 95% CI 0.58 to 1.20; very low-quality evidence). There was a decreased number of people with infections over 30 days in the people receiving prophylactic granulocyte transfusions in the intermediate-dose granulocyte group (1.0 x 10(10) to 4.0 x 10(10) granulocytes per day) (4 studies; 293 participants; RR 0.40, 95% CI 0.26 to 0.63, low-quality evidence).There was a decreased number of participants with bacteraemia and fungaemia in the participants receiving prophylactic granulocyte transfusions (nine studies; 609 participants; RR 0.45, 95% CI 0.30 to 0.65, low-quality evidence).There was no difference in the number of participants with localised bacterial or fungal infection in the participants receiving prophylactic granulocyte transfusions (six studies; 296 participants; RR 0.75, 95% CI 0.50 to 1.14; very low-quality evidence).Serious adverse events were only reported for participants receiving granulocyte transfusions and donors of granulocyte transfusions. AUTHORS' CONCLUSIONS: In people who are neutropenic due to myelosuppressive chemotherapy or a haematopoietic stem cell transplant, there is low-grade evidence that prophylactic granulocyte transfusions decrease the risk of bacteraemia or fungaemia. There is low-grade evidence that the effect of prophylactic granulocyte transfusions may be dose-dependent, a dose of at least 10 x 10(10) per day being more effective at decreasing the risk of infection. There is insufficient evidence to determine any difference in mortality rates due to infection, all-cause mortality, or serious adverse events.

A randomized noninferiority crossover trial of corrected count increments and bleeding in thrombocytopenic hematology patients receiving 2- to 5- versus 6- or 7-day-stored platelets.

BACKGROUND: Bacterial screening offers the possibility of extending platelet (PLT) storage to Day 7. We conducted a noninferiority, crossover trial comparing PLTs stored for 6 or 7 days versus 2 to 5 days. STUDY DESIGN AND METHODS: Stable hematology patients were allocated to receive blocks of 2- to 5- and 6- or 7-day PLTs in random order. The primary outcome was the proportion of successful transfusions during the first block, defined as a corrected count increment (CCI) of more than 4.5 at 8 to 24 hours posttransfusion. RESULTS: Of 122 patients with an evaluable first block, 87 (71%) and 84 (69%) had successful transfusions after 2- to 5- and 6- or 7-day PLTs of mean (SD) ages of 3.8 (1.0) and 6.4 (0.5) days, respectively. Six- or 7-day PLTs were declared noninferior to 2- to 5-day PLTs since the upper confidence interval (CI) limit was less than the predefined noninferiority margin of 10% (95% CI, -14.0% to 9.1%; p = 0.766). Logistic regression analysis gave an adjusted odds ratio of 0.86 (95% CI, 0.47-1.58; p = 0.625). Mean (SD) 8- to 24-hour CCIs were 9.4 (7.9) and 7.7 (7.1) after transfusion with 2- to 5- or 6- or 7-day PLTs (95% CI, -3.31 to 0.03; p = 0.054). The proportions of days with bleeding scores of WHO Grade 2 or higher were 13% (38/297 days) and 11% (32/296 days; 95% CI, -3.2 to 7.2; p = 0.454). Median interval to next PLT transfusion (2 days) was unaffected (95% CI, -10.5 to 5.4; p = 0.531). CONCLUSION: In hematology patients, there was no evidence that 6- or 7-day PLTs were inferior to 2- to 5-day PLTs, as measured by proportion of patients with successful transfusions, bleeding events, or interval to next transfusion.

Diagnostic accuracy of routine antenatal determination of fetal RHD status across gestation: population based cohort study.

OBJECTIVES: To assess the accuracy of fetal RHD genotyping using cell-free fetal DNA in maternal plasma at different gestational ages. DESIGN: A prospective multicentre cohort study. SETTING: Seven maternity units in England. PARTICIPANTS: RhD negative pregnant women who booked for antenatal care before 24 weeks' gestation. INTERVENTIONS: Women who gave consent for fetal RHD genotyping had blood taken at the time of booking for antenatal care and, when possible, at other routine visits such as for Down's syndrome screening between 11 and 21 weeks' gestation, at the anomaly scan at 18-21 weeks, and in the third trimester when blood was taken for the routine antibody check. The results of cord blood analysis, done routinely in RhD negative pregnancies, were also obtained to confirm the fetal RHD genotyping. MAIN OUTCOME MEASURES: The accuracy of fetal RHD genotyping compared with RhD status predicted by cord blood serology. RESULTS: Up to four analyses per woman were performed in 2288 women, generating 4913 assessable fetal results. Sensitivity for detection of fetal RHD positivity was 96.85% (94.95% to 98.05%), 99.83% (99.06% to 99.97%), 99.67% (98.17% to 99.94%), 99.82% (98.96% to 99.97%), and 100% (99.59% to 100%) at <11, 11-13, 14-17, 18-23, and >23 completed weeks' gestation, respectively. Before 11 weeks' gestation 16/865 (1.85%) babies tested were falsely predicted as RHD negative. CONCLUSIONS: Mass throughput fetal RHD genotyping is sufficiently accurate for the prediction of RhD type if it is performed from 11 weeks' gestation. Testing before this time could result in a small but significant number of babies being incorrectly classified as RHD negative. These mothers would not receive anti-RhD immunoglobulin, and there would be a risk of haemolytic disease of the newborn in subsequent pregnancies.

Management of fetal hydrops due to maternal antibodies against a low incidence paternal red cell antigen: a novel insight from clinical practice.

A rare case of a low incidence red cell antigen causing severe fetal allo-immune red cell disease is presented. Discussion of how this can be diagnosed and successfully managed antenatally using middle cerebral artery Doppler ultrasound and maternal antibody titre levels for fetal surveillance and timing of intervention with intrauterine transfusion.

Guideline on the investigation and management of acute transfusion reactions. Prepared by the BCSH Blood Transfusion Task Force.

Although acute non-haemolytic febrile or allergic reactions (ATRs) are a common complication of transfusion and often result in little or no morbidity, prompt recognition and management are essential. The serious hazards of transfusion haemovigilance organisation (SHOT) receives 30-40 reports of anaphylactic reactions each year. Other serious complications of transfusion, such as acute haemolysis, bacterial contamination, transfusion-related acute lung injury (TRALI) or transfusion-associated circulatory overload (TACO) may present with similar clinical features to ATR. This guideline describes the approach to a patient developing adverse symptoms and signs related to transfusion, including initial recognition, establishing a likely cause, treatment, investigations, planning future transfusion and reporting within the hospital and to haemovigilance organisations. Key recommendations are that adrenaline should be used as first line treatment of anaphylaxis, and that transfusions should only be carried out where patients can be directly observed and where staff are trained in manging complications of transfusion, particularly anaphylaxis. Management of ATRs is not dependent on classification but should be guided by symptoms and signs. Patients who have experienced an anaphylactic reaction should be discussed with an allergist or immunologist, in keeping with UK resuscitation council guidelines.

The ins and outs of human reticulocyte maturation: autophagy and the endosome/exosome pathway.

The maturation of reticulocytes into functional erythrocytes is a complex process requiring extensive cytoplasmic and plasma membrane remodeling, cytoskeletal rearrangements and changes to cellular architecture. Autophagy is implicated in the sequential removal of erythroid organelles during erythropoiesis, although how this is regulated during late stages of erythroid differentiation, and the potential contribution of autophagy during reticulocyte maturation, remain unclear. Using an optimized ex vivo differentiation system for human erythropoiesis, we have observed that maturing reticulocytes are characterized by the presence of one or few large vacuolar compartments. These label strongly for glycophorin A (GYPA/GPA) which is internalized from the plasma membrane; however, they also contain organellar remnants (ER, Golgi, mitochondria) and stain strongly for LC3, suggesting that they are endocytic/autophagic hybrid structures. Interestingly, we observed the release of these vacuoles by exocytosis in maturing reticulocytes, and speculate that autophagy is needed to concentrate the final remnants of the reticulocyte endomembrane system in autophagosome/endosome hybrid compartments that are primed to undergo exocytosis.