Transfusion Setting Research Articles

Blood component transfusion and wastage rates in the setting of massive transfusion in three regional trauma centers.

The purpose of massive transfusion protocols (MTPs) is to provide large quantities of blood products rapidly to exsanguinating patients. The expected rates of blood product transfusion and wastage in this setting have not been defined. This study was undertaken to assess the transfusion and wastage rates for bleeding patients requiring emergency issue of blood components at three American Level I trauma centers. Three hospitals participated, all of which are Level I trauma centers that have MTPs in place where uncrossmatched red blood cells (RBCs) can be ordered with or without platelets (PLTs), plasma, and cryoprecipitate. Data on the transfusion, return to blood bank, and wastage rates were recorded on all products issued within 3 hours after MTP activation. The majority of products were issued to the emergency department and/or operating room at all three institutions (84%-95%). The percentage of RBCs, plasma, and PLTs transfused during MTPs were 39% to 65%, 43% to 66%, and 75% to 100%, respectively. Wastage rates were comparable for RBCs (0%-9%), plasma (0%-7%), and PLTs (0%-7%). Cryoprecipitate had the highest wastage rates at all three sites (7%-33%). A large portion of blood products issued during MTPs are not transfused. Some are wasted due to stringent storage requirements and/or limited shelf lives. The optimum ratio of transfused to returned products in these patients is likely to be determined more by clinical need than by transfusion service policy.

Bortezomib decreases the magnitude of a primary humoral immune response to transfused red blood cells in a murine model.

Few therapeutic options currently exist to prevent or to mitigate transfusion-associated red blood cell (RBC) alloimmunization. We hypothesized that bortezomib, a proteasome inhibitor currently being utilized for HLA alloantibody and ADAMTS13 autoantibody reduction, may be beneficial in a transfusion setting. Herein, we utilized a reductionist murine model to test our hypothesis that bortezomib would decrease RBC alloimmune responses. Wild-type mice were treated with bortezomib or saline and transfused with murine RBCs expressing the human KEL glycoprotein. Levels of anti-KEL immunoglobulins in transfusion recipients were measured by flow cytometry. The impact of bortezomib treatment on recipient plasma cells (PCs) and other immune cells was also assessed by flow cytometry and immunofluorescence. After bortezomib treatment, mice had a 50% reduction in splenic white blood cells and a targeted reduction in marrow PCs. Mice treated with bortezomib before the transfusion of KEL RBCs became alloimmunized in three of three experiments, although their serum anti-KEL IgG levels were 2.6-fold lower than those in untreated mice. Once a primary antibody response was established, bortezomib treatment did not prevent an anamnestic response from occurring. To the extent that these findings are generalizable to other RBC antigens and to humans, bortezomib monotherapy is unlikely to be of significant clinical benefit in a transfusion setting where complete prevention of alloimmunization is desirable. Given the impact on PCs, however, it remains plausible that bortezomib therapy may be beneficial for RBC alloimmunization prevention or mitigation if used in combination with other immunomodulatory therapies.

Association between Blood Transfusion, Transfusion Setting, and the Risk of Venous Thromboembolism in Patients with Isolated Orthopedic Trauma

Association between Blood Transfusion, Transfusion Setting, and the Risk of Venous Thromboembolism in Patients with Isolated Orthopedic Trauma

Clinically significant anti-KEL RBC alloantibodies are transferred by breast milk in a murine model.

Fetuses affected by maternal RBC alloantibodies may have prolonged anaemia after birth, leading one to question whether maternal alloantibody transfer may occur outside the placenta. In response to a recent publication describing breast milk transfer of clinically significant amounts of maternal antiplatelet IgA antibodies from mother to nursing infant, we hypothesized that maternal RBC alloantibodies may also be capable of being transferred in breast milk. The presence and clinical significance of breast milk alloantibody transfer were tested through a series of pregnancy, fostering and transfusion experiments, using a murine model in which transgenic RBCs express the human KEL glycoprotein. Maternal anti-KEL immunoglobulins, induced through transfusion or pregnancy, were detected in the aqueous phase of breast milk. Further, efficient transfer of maternal anti-KEL IgG and IgA to nursing pups was observed in fostering experiments. The breast milk-acquired alloantibodies were clinically significant in wild-type pups in a transfusion setting, binding to 'incompatible' KEL RBCs and leading to premature clearance from the circulation. Although breast milk-acquired alloantibodies also bound to the RBCs of transgenic KEL-positive fostered pups, no anaemia resulted. Taking these murine data in combination with recently published human data of maternal antiplatelet IgA antibodies in breast milk leading to sequelae in some infants, it is theoretically possible that maternal anti-RBC IgA alloantibodies may also be transferred in human breast milk and may lead to sequelae in some infants under some circumstances.

SELECTION OF THERAPEUTIC TACTICS FOR EARLY ANEMIA OF PREMATURE INFANTS WITH VERY LOW OR EXTREMELY LOW BIRTH WEIGHT: RETROSPECTIVE STUDY RESULTS

Background: Early anemia of prematurity (EAP) is a serious issue of contemporary neonatology due to increasing survivability of premature infants. One of the most efficient preventive methods is extreme prematurity prevention. At the same time, efficacy of different methods of EAP therapy remains undetermined. Objective: Our aim was to compare efficacy of erythrocyte-containing donor blood components (packed red cells, erythrocytic suspension) and recombinant epoetin beta for treating premature infants with EAP. Methods: The retrospective cohort study provided analysis of data of premature infants (gestation age — 27–32 weeks) born with very low (VLBW) and extremely low birth weight (ELBW) and EAP (hemoglobin < 110 g/l, hematocrit < 27%, reticulocyte share < 20‰, normochromia, normocytosis; all criteria must have been met). We determined primary hematological morphological parameters and population structure of umbilical (at birth) and peripheral blood (after 30 days of treatment) leukocytes. Results: 32 premature infants with EAP underwent donor blood component transfusions, 26 — recombinant epoetin beta injections. The groups were comparable in terms of the primary clinical laboratory parameters. In the donor blood component group, we observed lower hemoglobin concentration (108 ± 17 vs. 119 ± 16 g/l in the epoetin beta group; p = 0.07) and reticulocyte share (3.7 ± 1.5 vs. 8.7 ± 1.7‰, respectively; p = 0,053) at the age of 1 month. We revealed a drop in cell immunity parameters in the setting of donor blood component transfusions: CD4+ lymphocyte share — down to 32,2 ± 14,0% (in the epoetin beta group; p = 0.055); CD8+ lymphocyte share — down to 21,2 ± 7,1% (in the epoetin beta group; p = 0.050). Conclusion: Epoetin beta is more efficient in terms of EAP correction in premature infants with VLBW and ELBW that erythrocyte-containing donor blood component transfusions. The latter are characterized by adverse effect on cell immunity parameters.

Identified metabolic signature for assessing red blood cell unit quality is associated with endothelial damage markers and clinical outcomes.

There has been interest in determining whether older red blood cell (RBC) units have negative clinical effects. Numerous observational studies have shown that older RBC units are an independent factor for patient mortality. However, recently published randomized clinical trials have shown no difference of clinical outcome for patients receiving old or fresh RBCs. An overlooked but essential issue in assessing RBC unit quality and ultimately designing the necessary clinical trials is a metric for what constitutes an old or fresh RBC unit. Twenty RBC units were profiled using quantitative metabolomics over 42 days of storage in SAGM with 3- to 4-day time intervals. Metabolic pathway usage during storage was assessed using systems biology methods. The detected time intervals of the metabolic states were compared to clinical outcomes. Using multivariate statistics, we identified a nonlinear decay process exhibiting three distinct metabolic states (Days 0-10, 10-17, and 17-42). Hematologic variables traditionally measured in the transfusion setting (e.g., pH, hemolysis, RBC indices) did not distinguish these three states. Systemic changes in pathway usage occurred between the three states, with key pathways changing in both magnitude and direction. Finally, an association was found between the time periods of the metabolic states with the clinical outcomes of more than 280,000 patients in the country of Denmark transfused over the past 15 years and endothelial damage markers in healthy volunteers undergoing autologous transfusions. The state of RBC metabolism may be a better indicator of cellular quality than traditional hematologic variables.

Mechanisms underlying red‐cell alloimmunization in sickle‐cell disease

Red blood cell transfusion is a life‐sustaining therapy that has decreased morbidity and mortality in sickle‐cell disease (SCD). The major immunological risk of transfusion is erythrocyte alloimmunization, which can lead to severe complications, such as delayed haemolytic transfusion reactions (DHTR) and problems finding compatible units, delaying transfusion. In this review, we discuss the known mechanisms of alloimmunization in sickle‐cell disease and the extent to which findings from mouse models of immunization can be extrapolated to the setting of transfusion in humans with SCD. We also consider preventive treatments, such as B‐lymphocyte depletion therapy.

Impact of Genetic Predispositions, Diet, and Environment on Storage of Red Blood Cells

It remains controversial whether or not transfusions of human red blood cells (RBCs), which have been refrigerator-stored for extended time intervals, induce or exacerbate clinically-relevant adverse effects in recipients. The described effects include infection, inflammation, renal dysfunction, thrombosis, and even death. It is also controversial whether such effects are seen in particular patient populations predisposed to these types of complications, or whether they are universal. To this end, multiple bench research studies, clinical/translational studies, and prospective randomized controlled trials are currently investigating these issues. What is not controversial is that refrigerated storage produces the "RBC storage lesion" and that this worsens in proportion to increasing storage time, such that, at the FDA-mandated 42-day outdate, on average, only 75% of transfused donor RBCs are still circulating in the recipient at 24-hours post-transfusion. It is also not controversial that RBCs obtained from some healthy volunteer donors do not store well and, at outdate, have a 24-hour post-transfusion recovery (PTR) of significantly less than 75% (i.e., "poor storers"). Analogously, RBCs from some donors store extremely well and may exhibit virtually 100% 24-hour PTR at outdate (i.e., "super storers"). Understanding the underlying mechanisms for these phenomena would allow implementation of various approaches to improve the blood supply, with an ultimate goal of virtually 100% 24-hour PTR and normal long-term circulatory lifespan of transfused RBCs. This goal is especially relevant in the chronic transfusion setting (e.g., patients with sickle cell anemia or beta-thalassemia). Similar observations have been made about hemolysis ex vivo (i.e., "in the bag") during refrigerated storage, which influences the amount of free hemoglobin infused during the transfusion procedure. There is also evidence that these RBC storage characteristics are stable in "poor" and "super" donors, suggesting that genetic, dietary, and/or environmental factors are involved. Indeed, using inbred strains of mice, there is clear evidence that genetic and dietary factors can significantly influence donor RBC storage quality, when measured as 24-hour PTR and/or ex vivo hemolysis. In addition, human genetic polymorphisms, particularly in racial/ethnic groups enriched for malaria-induced traits, result in abnormal expression or abnormal function of various RBC proteins, including hemoglobin and cytosolic enzymes, such as glucose-6-phosphate dehydrogenase. There is increasing evidence that these polymorphisms can influence the ability of human RBCs to tolerate standard conditions of refrigerated storage. Harnessing this information will result in new methods for improving the quality of the blood supply and, consequently, improving patient responses to transfusion therapy. Disclosures No relevant conflicts of interest to declare.

Evaluation of HIV testing algorithms in Ethiopia: the role of the tie-breaker algorithm and weakly reacting test lines in contributing to a high rate of false positive HIV diagnoses

BackgroundIn Ethiopia a tiebreaker algorithm using 3 rapid diagnostic tests (RDTs) in series is used to diagnose HIV. Discordant results between the first 2 RDTs are resolved by a third ‘tiebreaker’ RDT. Médecins Sans Frontières uses an alternate serial algorithm of 2 RDTs followed by a confirmation test for all double positive RDT results. The primary objective was to compare the performance of the tiebreaker algorithm with a serial algorithm, and to evaluate the addition of a confirmation test to both algorithms. A secondary objective looked at the positive predictive value (PPV) of weakly reactive test lines.MethodsThe study was conducted in two HIV testing sites in Ethiopia. Study participants were recruited sequentially until 200 positive samples were reached. Each sample was re-tested in the laboratory on the 3 RDTs and on a simple to use confirmation test, the Orgenics Immunocomb Combfirm® (OIC). The gold standard test was the Western Blot, with indeterminate results resolved by PCR testing.Results2620 subjects were included with a HIV prevalence of 7.7%. Each of the 3 RDTs had an individual specificity of at least 99%. The serial algorithm with 2 RDTs had a single false positive result (1 out of 204) to give a PPV of 99.5% (95% CI 97.3%-100%). The tiebreaker algorithm resulted in 16 false positive results (PPV 92.7%, 95% CI: 88.4%-95.8%). Adding the OIC confirmation test to either algorithm eliminated the false positives. All the false positives had at least one weakly reactive test line in the algorithm. The PPV of weakly reacting RDTs was significantly lower than those with strongly positive test lines.ConclusionThe risk of false positive HIV diagnosis in a tiebreaker algorithm is significant. We recommend abandoning the tie-breaker algorithm in favour of WHO recommended serial or parallel algorithms, interpreting weakly reactive test lines as indeterminate results requiring further testing except in the setting of blood transfusion, and most importantly, adding a confirmation test to the RDT algorithm. It is now time to focus research efforts on how best to translate this knowledge into practice at the field level.Trial registrationClinical Trial registration #: NCT01716299

The Effect of Variation in Donor Platelet Function on Transfusion Outcome: A Semi-Randomised, Double Blind, Controlled Trial (PROmPT)

Genetic variation is known to account for up to 70% of the wide variation in platelet function observed in healthy individuals. We have shown that platelet concentrates (PC) that are highly activated when collected by apheresis are produced from donors whose platelets are highly responsive to adenosine diphosphate (ADP) and collagen related peptide (CRP-XL) in vitro(high responder donors) with activation being measured by P-selectin expression and fibrinogen binding. The effect of this variation in donors on the outcome from platelet transfusion is unknown.The aim of the PROmPT trial (Platelet Responsiveness and Outcome from Platelet Transfusion, ISRCTN 56366401) was to test the hypothesis that PC following transfusion from high responder donors are cleared more rapidly from the circulation than PC from low responder donors.MethodWe established a cohort of 1,000 blood donors phenotyped for responsiveness to CRP (0.1-0.5 µg/mL) or ADP (10-7M) by flow cytometry. A sub-set of these individuals (26 high and 19 low responder donors) who reproducibly had global responses, i.e. not outliers for just one agonist, in the top and bottom 10% of the cohort were selected to supply apheresis platelets collected on the Terumo Trima system for the trial.The trial was designed as a parallel group, semi-randomised double-blinded trial in stable haematology patients who required prophylactic platelet transfusions. Based on 80% power, a 5% significance level, and a presumed 10% dropout, 100 patients (with the aim of 50 receiving a unit from high responders and 50 from low responders) were required to detect a mean difference of 7x109/L in the primary endpoint of the 1 hour (10-90 min) count increment (CI) between the high and low responder PC.Patients were randomised to receive a single PC from either a high or low responder donor when both were available. If only one type of PC was available then patients received that PC. Patients with factors known to affect platelet CI were excluded. In addition, 30 patients acted as controls, receiving non-trial PC from random donors. PCs were ABO and Rh compatible. Patients were followed up for 5 days or until their next platelet transfusion.Secondary outcomes included an assessment of bleeding score (modified WHO score) both by the patient and the clinician, 24 hour (12-36 hours) CI, as well as time to next platelet transfusion, and red cell transfusion requirements. CIs were adjusted for confounding factors that affect platelet increments, these were age and dose of PC, and body surface area.ResultsBaseline characteristics of patients were adequately balanced between groups. Fifty one patients received a PC from low responder donors, and 49 from high responder donors (47 of which were randomised and 53 non-randomised) and 30 patients received non-trial units (2 non trial transfusions were excluded from final analysis).There was no significant difference in the adjusted 1 hour CI, in patients receiving platelets from high or low responder donors (high response 21.04 versus low response 23.34x109/L; difference 2.30, 95%CI -1.09 to 5.69, p = 0.18) or the 24 hour platelet CI (high response 12.9 versus low response 14.31x109/L; difference 1.41, 95% CI -1.96 to 4.78, p = 0.41).There were no significant differences in all other secondary outcomes between patients receiving PC from high or low responder donors, including maximum bleeding scores (odds ratio 0.78, 95%confidence interval 0.29 to 2.16, p=0.64) and bleeding rates (number of days with Grade 2-4 bleed) (rate ratio was 0.70, 95% confidence interval 0.16 to 2.97, p = 0.63).In addition, there was no significant difference in 1 hour CI between patients receiving non-trial units and those from high (p = 0.28) or low responders (p = 0.95) or in any secondary outcomes.ConclusionsResults from this trial suggest that in a setting of prophylactic transfusion, the platelet responsiveness of the donor does not affect platelet count increments, bleeding scores, inter-transfusion interval or red cell usage in recipients. Further studies will be required to determine whether PC derived from high responders may be more efficacious in patients who are actively bleeding at the time of transfusion. DisclosuresNo relevant conflicts of interest to declare.

Damage Control Resuscitation Protocol and the Management of Open Abdomens in Trauma Patients

Although the use of damage control laparotomy (DCL) is well established, the effect of damage control resuscitation (DCR) on the management of open abdomens is relatively poorly studied. The aim of the present study was to determine the predictors for failure to achieve primary fascial closure (PFC) after DCL in the setting of a massive transfusion (MT) and DCR. This is a retrospective review over a 12-year period of all patients that underwent MT and DCL. Patients who achieved PFC were compared with those who did not (NPFC). Student's t tests were used to compare the two groups. A multiple logistic regression model was performed to identify independent risk factors for failure to attain PFC. Of 174 patients, 101 achieved PFC. Mean (± standard deviation) age was 35.6 ± 14.9 years for PFC and 36.3 ± 14.0 years for NPFC (P = 0.75). Admission Glasgow Coma Scale score was 11.4 ± 4.6 for PFC and 10.6 ± 5.0 for NPFC (P = 0.25). Initial lactate (7.3 ± 3.8 vs 7.7 ± 4.1, P = 0.50), hemoglobin (11.3 ± 1.9 vs 11.0 ± 2.2, P = 0.43), systolic blood pressure (108 ± 44 vs 107 ± 35, P = 0.82), Injury Severity Score (34 ± 14 vs 36 ± 15, P = 0.32), and abdominal Abbreviated Injury Score (3.6 ± 1.1 vs 3.9 ± 1.0, P = 0.13) were similar between the two groups. There was no difference in total blood products administered at 24 hours (46 ± 26 vs 49 ± 29 units, P = 0.45). Logistic regression identified increasing volume of crystalloid at 24 hours (odds ratio, 0.86; 95% confidence interval, 0.74 to 0.99; P = 0.047), earlier operative year (2.1; 1.52 to 2.91; P < 0.001), and increased number of procedures (0.32, 0.18 to 0.58; P < 0.001) as independent predictors for failure to obtain PFC. Injury severity is not associated with failure to achieve PFC, whereas administration of large-volume crystalloid resuscitation, increasing number procedures, and earlier year of DCL are independent predictors for failure to achieve PFC. Application of DCR to DCL techniques results in an improvement in ability to achieve PFC.

Detection and identification of platelet-associated alloantibodies by a solid-phase modified antigen capture enzyme-linked immunosorbent assay method and its correlation to platelet refractoriness in multiplatelet concentrate–transfused patients

Abstract Platelets express a variety of polymorphic glycoproteins (GPs), such as GPIIb/IIIa, GPIb/IX, GPIa/IIa, GPIV, and class I human leukocyte antigen. In the platelet transfusion setting, alloimmunization involves the production of antibodies against these glycoproteins. Patients transfused with multiple units of platelet concentrates for longer periods are the main individuals with platelet alloimmunization. This study was performed to detect the development of platelet antibodies in patients who are transfused with multiple units of leukodepleted platelet concentrates, such as those with hemato-oncologic diseases and bone marrow failure syndromes. The method used was solid-phase modified antigen capture enzyme-linked immunosorbent assay. Platelet refractoriness was assessed by measuring the corrected count increment at 1 and 24 hours after transfusion. Immunohematology 2014;30:123–125.

Why do we use serological blood group phenotype determination in chronically transfused patients?

Why do we use serological blood group phenotype determination in chronically transfused patients?

Paradoxical Effects Of Tumor Necrosis Factor-Alpha On Endothelial Adhesion Of Stored Human Red Blood Cells

IntroductionThe duration of red blood cell (RBC) storage is currently being examined as a possible determinant of clinical outcomes in transfused patients in large randomized trials in several patient populations, as well as in preclinical models. Biochemical and functional changes coincident with blood storage, referred to as the “storage lesion,” are numerous and complex. Longer storage periods have, for example, been linked to increased tendency of RBCs to adhere to endothelium. How the proadhesive effect of storage influences the transfusion recipient might depend in part on preexisting comorbidities, consistent with a “two-hit” model of transfusion morbidity. We therefore developed a two-hit in vitro model using older stored RBCs and TNF-α pretreatment (activation) of HUVECs in order to better understand mechanisms of post-transfusion complications related to RBC adhesion. MethodsRed blood cell (RBC) preparation and labeling: Using an IRB-approved protocol, stored packed RBC segments stored in additive solution (AS)-3 were obtained at 35-42 days storage from the Transfusion Service at Duke Hospital. The stored RBCs were removed aseptically and washed 3 times with PBS, labeled with fluorescent dye PKH26, and allowed to incubate for 3 minutes. BSA (1%) in DPBS was added, and after one minute, the labeled cells were washed three times in PBS with Ca++ and Mg++ while avoiding exposure to light. Finally 5 µL of labeled RBCs was suspended in 3 mL of PBS for adhesion assays.Adhesion assaysHuman umbilical vein endothelial cells (HUVECs), grown to confluence on glass slides precoated with a 2% gelatin solution in a 5% CO2 incubator at 37.1°C, were placed in a graduated height-flow chamber. The height was measured at 7 different points along the chamber. After 15 minutes of PBS flow (2 mL min-1), the RBC sample was introduced to the chamber slowly at a rate of 1.5 mL min-1. The RBCs were then allowed to incubate without flow for 5 minutes, and the number of adhered cells at each location (height) was recorded. After 5 minutes of fluidic flow with PBS, the number of adherent cells at each location, corresponding to varying shear stresses, was counted. Percent adhesion and shear stress were calculated at each height.TNF-α treatment of HUVECs: Where indicated, TNF-α (20 µL) was added to 20 mL of cell media to yield a final concentration of 10 ng mL-1, and allowed to incubate overnight (16 hours). ResultsAdhesion of 35-42-days stored RBCs to non-activated HUVECs varied widely, as reported, and at shear stresses of 1, 2, and 5 dynes/cm2 was 42.92%, 10.77%, and 2.157% respectively, with a typical inverse relation to shear stress (p<0.005). Surprisingly, adhesion of stored RBCs to TNF-α-pretreated HUVECs was consistently lower than that to non-pretreated HUVECs. Mean adhesion of stored RBCs to TNF-α-pretreated HUVECs at 1, 2, and 5 dynes/cm2 was 15.43%, 6.120%, and 1.819%. [Display omitted] SummaryIn summary, we find that endothelial adhesion of stored RBCs nearing expiration tends to be inhibited rather than increased by prior treatment of HUVECs with the cytokine TNF-α. Since these stored RBCs had been pre-storage leukoreduced, it is unlikely that there are leukocyte-related confounders. It is possible, therefore, that TNF-α confers a protective effect against RBC adhesion in the microcirculation in the setting of transfusion of older stored RBCs. The mechanism of the paradoxical TNF-α effect is currently under investigation and may involve nitric oxide, which is deficient in stored RBCs. Adverse events related to the RBC storage lesion may depend in a critical and complex manner on the underlying pathophysiology. Disclosures:No relevant conflicts of interest to declare.

West Nile virus in the transfusion setting with a special focus on Italian preventive measures adopted in 2008-2012 and their impact on blood safety.

. The majority of WNV infections in humans are asymptomatic while approximately 20% of infected individuals develop, after an incubation period of 3-14 days, a mild febrile illness for 3-6 days (West Nile fever, WNF) characterised by a variety of non-specific symptoms that do not allow WNF to be distinguished from other infectious illnesses on clinical examination. In less than 1% of infected individuals, particularly the elderly or immunocompromised subjects

A comprehensive survey of both RHD and RHCE allele frequencies in sub‐Saharan Africa

The RH system is one of the most polymorphic blood group systems with numerous allele variants affecting Rh polypeptides expression. This complexity is at the origin of difficulties for transfusion of African patients especially sickle cell disease patients requiring chronic transfusion therapy with high risk of immunization. As a complete survey of RH variants is lacking in African populations, we performed red blood cell genotyping to determine the type and frequency of RHD and RHCE alleles in sub-Saharan African populations. A total of 347 blood samples were collected from individuals of six nonpygmoid and three pygmoid populations. RH typing was performed using two single-tube multiplex polymerase chain reaction amplifications (BioArray Solutions, Immucor). All six sub-Saharan nonpygmoid populations exhibited constant variety in both type and frequency of aberrant RHD and RHCE alleles. Predicted partial RH1 (1.8%) and RH5 (0.9%) phenotypes were less than expected. Conversely, predicted partial phenotype RH2 (5.5%) was frequent. Data confirmed the high frequency of samples positive for the non-clinically significant RH10/RH20 antigens (39.5%) and revealed a high frequency of RH54 (DAK, 8.1%). The pygmoid groups showed higher percentages of predicted partial RH antigens and greater heterogeneity reflecting wide genetic differentiation. Our data show that frequencies of aberrant RHD and RHCE alleles were similar, irrespective of location and ethnicity. In view of the predicted frequencies and relative clinical significance of both private antigens and high-prevalence antigens absent, the most relevant assays for individuals of African descent in a transfusion setting are for 1) partial RH2 in the patient and 2) RH54 (DAK) in the donor.

Alloantibodies to a paternally derived RBC KEL antigen lead to hemolytic disease of the fetus/newborn in a murine model

AbstractExposure to nonself red blood cell (RBC) antigens, either from transfusion or pregnancy, may result in alloimmunization and incompatible RBC clearance. First described as a pregnancy complication 80 years ago, hemolytic disease of the fetus and newborn (HDFN) is caused by alloimmunization to paternally derived RBC antigens. Despite the morbidity/mortality of HDFN, women at risk for RBC alloimmunization have few therapeutic options. Given that alloantibodies to antigens in the KEL family are among the most clinically significant, we developed a murine model with RBC-specific expression of the human KEL antigen to evaluate the impact of maternal/fetal KEL incompatibility. After exposure to fetal KEL RBCs during successive pregnancies with KEL-positive males, 21 of 21 wild-type female mice developed anti-KEL alloantibodies; intrauterine fetal anemia and/or demise occurred in a subset of KEL-positive pups born to wild type, but not agammaglobulinemic mothers. Similar to previous observations in humans, pregnancy-associated alloantibodies were detrimental in a transfusion setting, and transfusion-associated alloantibodies were detrimental in a pregnancy setting. This is the first pregnancy-associated HDFN model described to date, which will serve as a platform to develop targeted therapies to prevent and/or mitigate the dangers of RBC alloantibodies to fetuses and newborns.

Partial Manual Exchange Reduces Iron Accumulation During Chronic Red Cell Transfusions for Sickle Cell Disease

Iron overload is an inevitable consequence of chronic red cell transfusions without erythrocytapheresis or chelation therapy. The effectiveness of partial manual exchange, a technique used to slow iron loading, has not been evaluated. We evaluated all children with sickle cell disease (SCD) receiving chronic transfusion to identify chelation-naive subjects who had quantitative liver iron concentration (LIC) studies. Seventeen chelation-naive children with SCD received a median of 29 transfusions before first LIC determination. Serum ferritin concentrations were assessed before each transfusion. The mean volume of blood phlebotomized before each transfusion was 5.1±1.8 mL/kg, which cumulatively resulted in a calculated median of 35.0 mg/kg iron removal. Using linear regression, pretransfusion phlebotomy resulted in a statistically significant reduction in ferritin (-8.8 ng/mL of ferritin for each mg/kg of iron phlebotomized, P=0.02). A reduction in LIC from pretransfusion phlebotomy could not be established (P=0.4). Partial manual exchanges appear to be an effective strategy for slowing the pace of iron loading in the setting of chronic transfusion for SCD.

Does plasma transfusion portend pulmonary dysfunction? A tale of two ratios

An unresolved concern regarding resuscitation in the setting of massive hemorrhage is potential lung injury from the transfusion of relatively more plasma-rich components. However, the association between plasma-to-packed red blood cell (PRBC) ratio and subsequent pulmonary dysfunction remains unclear. The purpose of this study was to evaluate the impact of plasma/PRBC on PaO2-to-FIO2 (P/F) ratio in the setting of massive transfusion (MT). During a 5.5-year period, prospective data were collected on trauma patients who underwent MT, defined as 10 or more units of PRBC transfusion by completion of hemorrhage control. Deaths within 48 hours of arrival were excluded. Acute lung injury (ALI) and adult respiratory distress syndrome (ARDS) were defined as P/F ratio of less than 300 and less than 200 at 48 hours, respectively. Stepwise multiple regression analysis was performed to determine variables significantly associated with P/F ratio. A total of 199 patients met inclusion criteria; 159 (80%) developed ALI, and 105 (53%) developed ARDS. ALI and ARDS were both associated with subsequent mortality: ARDS at 24% versus no ARDS at 10% (p < 0.05) and ALI at 21% versus no ALI at 2.5% (p < 0.05). Paradoxically, patients with P/F ratio of 300 or greater were found to have received more plasma (5.6 U vs. 4.3 U, p < 0.05) and higher plasma-to-PRBC ratio (1:2 vs. 1:3, p < 0.05) at completion of hemorrhage control. Stepwise multiple regression analysis, however, identified age (p < 0.001) and chest Abbreviated Injury Scale (AIS) score (p = 0.04), but not plasma/PRBC (p = 0.10), to be independent determinants of P/F ratio at 48 hours. In this cohort of MT patients who survived beyond the first 48 hours, pulmonary dysfunction developed in the majority and was associated with a 10-fold higher risk of subsequent death. However, plasma-to-RBC ratio achieved during hemorrhage control had neither a positive nor a negative impact on subsequent P/F ratio. In fact, only unalterable patient factors including age and severity of thoracic injury were associated with subsequent P/F ratio. Prognostic study, level III.

Cystathionine Β-Synthase Deficiency, Turner Syndrome and İmmune Hydrops Fetalis in a Newborn: A Rare Coincidence

Cystathionine β-synthase (CBS) deficiency is a rare inborn error of amino acid metabolism affecting energy supply at the cellular level. Neonatal screening allows early presymptomatic diagnosis and better outcome, by preventing the complications like thrombotic disease. Here we present a female newborn baby with immune hydrops fetalis and mosaic Turner syndrome who has incidentally been early diagnosed with CBS deficiency upon detection of increased methionine on serum amino acid chromatography. The patient was unresponsive to pridoxine treatment which was compatible with p.S349N mutation detected on both alleles of cystathionine β-synthase gene. We would like to stress the point that CBS deficiency can be diagnosed by screening even in the setting of exchange transfusions and amino acid paper chromotography is a cheap and valuable metabolic screening tool in experienced hands. Since routine newborn screening for many metabolic diseases is currently not practiced in Turkey, all newborns born to families in which previous siblings had died due to unknown cause should be evaluated by amino acid paper chromotography and by other conventional metabolic tests when necessary.