Female donors and transfusion-related acute lung injury: A case-referent study from the International TRALI Unisex Research Group

Neonatal Thrombocytopenia: Factors Associated With the Platelet Count Increment Following Platelet Transfusion

OBJECTIVE

To understand better those factors relevant to the increment of rise in platelet count following a platelet transfusion among thrombocytopenic neonates.

STUDY DESIGN

We reviewed all platelet transfusions over 6 years in our multi-neonatal intensive care unit system. For every platelet transfusion in 8 neonatal centers we recorded: (1) platelet count before and after transfusion; (2) time between completing the transfusion and follow-up count; (3) transfusion volume (mL/kg); (4) platelet storage time; (5) sex and age of platelet donor; (6) gestational age at birth and postnatal age at transfusion; and magnitude of rise as related to (7) pre-transfusion platelet count, (8) method of enhancing transfusion safety (irradiation vs pathogen reduction), (9) cause of thrombocytopenia, and (10) donor/recipient ABO group.

RESULTS

We evaluated 1797 platelet transfusions administered to 605 neonates (median one/recipient, mean 3, and range 1-52). The increment was not associated with gestational age at birth, postnatal age at transfusion, or donor sex or age. The rise was marginally lower: (1) with consumptive vs hypoproductive thrombocytopenia (P < .001); (2) after pathogen reduction (P < .01); (3) after transfusing platelets with a longer storage time (P < .001); and (4) among group O neonates receiving platelets from non-group O donors (P < .001). Eighty-seven neonates had severe thrombocytopenia (<20 000/μL). Among these infants, poor increments and death were associated with the cause of the thrombocytopenia.

CONCLUSION

The magnitude of post-transfusion rise was unaffected by most variables we studied. However, the increment was lower in neonates with consumptive thrombocytopenia, after pathogen reduction, with longer platelet storage times, and when not ABO matched.

Platelet and cryoprecipitate transfusions from female donors improve coagulopathy in vitro

BACKGROUND

Females are relatively hypercoagulable compared with males, with increased platelet aggregation and improved clot dynamics. However, sex differences in coagulation have not yet been considered in transfusion guidelines. Therefore, our objective was to evaluate hemostatic differences in sex concordant and sex discordant cryoprecipitate and platelet transfusions. We hypothesized that transfusion of blood products from female donors results in improved coagulopathy compared with male blood products.

METHODS

This was a cohort study evaluating sex dimorphisms in coagulation assays and clotting factors in healthy volunteer plasma and cryoprecipitate. Sex dimorphisms in transfusions were evaluated using an in vitro coagulopathy model. Female or male platelets or single-donor cryoprecipitate was added to "recipient" whole blood after dilution of recipient blood with citrated saline to provoke a coagulopathic profile. Citrated native thromboelastography was then performed. Liquid chromatography/mass spectroscopy was performed on single-donor cryoprecipitate to evaluate sex dimorphisms in the proteome of cryoprecipitate.

RESULTS

Females have an increased proportion of functional fibrinogen. Transfusion of female-donor platelets and cryoprecipitate induces a larger decrease in R time and greater increase in angle than male-donor platelets or cryoprecipitate. Female-donor cryoprecipitate has increased factor V and factor XIII compared with male cryoprecipitate, and comprehensive proteomics revealed sex differences in several proteins with potential immunological significance.

CONCLUSION

Platelets and cryoprecipitate from female donors improve coagulopathy more than male blood products in vitro. Increased factor V and factor XIII activity as well as increased fibrinogen activity in female donors appears to drive this disparity. Sex differences in the proteome of cryoprecipitate may influence how transfusions modulate the thromboinflammation of trauma. The differing hemostatic profiles of female and male blood products suggest the potential role of sex-specific transfusions guidelines in hemostatic resuscitation.

Preterm infant circulating sex steroid levels are not altered by transfusion with adult male plasma: a retrospective multicentre cohort study

OBJECTIVE

To determine if plasma transfusions with male donor plasma to very preterm infants affect circulatory levels of sex steroids.

DESIGN AND PATIENTS

Retrospective multicentre cohort study in 19 infants born at gestational age <29 weeks requiring plasma transfusion during their first week of life.

SETTING

Three neonatal intensive care units in Sweden.

MAIN OUTCOME MEASURES

Concentrations of sex steroids and sex hormone-binding globulin (SHBG) in donor plasma and infant plasma measured before and after a plasma transfusion and at 6, 12, 24 and 72 hours.

RESULTS

The concentrations of progesterone, dehydroepiandrosterone and androstenedione were significantly lower in donor plasma than in infant plasma before the transfusion (median (Q1-Q3) 37.0 (37.0-37.0), 1918 (1325-2408) and 424 (303-534) vs 901 (599-1774), 4119 (2801-14 645) and 842 (443-1684) pg/mL), while oestrone and oestradiol were higher in donor plasma (17.4 (10.4-20.1) and 16.0 (11.7-17.2) vs 3.1 (1.1-10.2) and 0.25 (0.25-0.25) pg/mL). Median testosterone and dihydrotestosterone (DHT) levels were 116-fold and 21-fold higher in donor plasma than pre-transfusion levels in female infants, whereas the corresponding difference was not present in male infants. Plasma sex steroid levels were unchanged after completed transfusion compared with pre-transfusion levels, irrespective of the gender of the receiving infant. The SHBG concentration was significantly higher in donor than in recipient plasma (22.8 (17.1-33.5) vs 10.2 (9.1-12.3) nmol/L) before transfusion but did not change in the infants after the transfusion.

CONCLUSIONS

A single transfusion of adult male plasma to preterm infants had no impact on circulating sex steroid levels.

Interferon-α2 Auto-antibodies in Convalescent Plasma Therapy for COVID-19

Purpose

To study the effect of interferon-α2 auto-antibodies (IFN-α2 Abs) on clinical and virological outcomes in critically ill COVID-19 patients and the risk of IFN-α2 Abs transfer during convalescent plasma treatment.

Methods

Sera from healthy controls, cases of COVID-19, and other respiratory illness were tested for IFN-α2 Abs by ELISA and a pseudo virus–based neutralization assay. The effects of disease severity, sex, and age on the risk of having neutralizing IFN-α2 Abs were determined. Longitudinal analyses were performed to determine association between IFN-α2 Abs and survival and viral load and whether serum IFN-α2 Abs appeared after convalescent plasma transfusion.

Results

IFN-α2 neutralizing sera were found only in COVID-19 patients, with proportions increasing with disease severity and age. In the acute stage of COVID-19, all sera from patients with ELISA-detected IFN-α2 Abs (13/164, 7.9%) neutralized levels of IFN-α2 exceeding physiological concentrations found in human plasma and this was associated with delayed viral clearance. Convalescent plasma donors that were anti-IFN-α2 ELISA positive (3/118, 2.5%) did not neutralize the same levels of IFN-α2. Neutralizing serum IFN-α2 Abs were associated with delayed viral clearance from the respiratory tract.

Conclusions

IFN-α2 Abs were detected by ELISA and neutralization assay in COVID-19 patients, but not in ICU patients with other respiratory illnesses. The presence of neutralizing IFN-α2 Abs in critically ill COVID-19 is associated with delayed viral clearance. IFN-α2 Abs in COVID-19 convalescent plasma donors were not neutralizing in the conditions tested.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10875-021-01168-3.

Alteration in biochemical parameters during plateletpheresis in healthy donors: A compendious analysis

OBJECTIVES

During plateletpheresis, citrate induces hypocalcemia and hypomagnesemia, which are usually transient and self-limiting, but they can lead to significant donor discomfort. The aim of study was to determine the effect of citrate infusion on a multitude of biochemical parameters during plateletpheresis in healthy donors and to correlate changes with adverse donor reactions.

METHODS

The study was conducted on 60 healthy plateletpheresis donors. Blood samples were drawn on three occasions, a baseline pre-donation sample, 30min at start of procedure and 30min post procedure. Heparinized samples were taken to measure ionized calcium and plain samples to measure serum calcium, serum magnesium, parathyroid hormone, total protein and serum albumin.

RESULTS

There was statistically significant decline in mean total calcium (9.27±0.66mg/dl to 8.72±0.87mg/dl) and ionized calcium (3.8±0.51mg/dl to 2.9±0.67mg/dl) from baseline until 30min after the start of procedure respectively. A significant fall in serum magnesium, total protein and serum albumin was observed. The mean parathyroid hormone showed significant increase from baseline levels till at the completion of procedure (19.94±12.1pg/ml to 92.08±36.78pg/ml). If the yield was set constant, there was negative correlation between ACD used and pre-donation platelet count. Majority of adverse donor reactions were hypocalcemic reactions, which were more with Amicus double yield plateletpheresis and were managed with calcium supplementation.

CONCLUSION

Plateletpheresis induces marked reduction in serum calcium and magnesium levels. Moreover, increase in parathyroid hormone levels was significant. In addition, decline in total protein and serum albumin may be a concern in donors also participating in plasmapheresis.

A consensus redefinition of transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a serious complication of blood transfusion and is among the leading causes of transfusion-related morbidity and mortality in most developed countries. In the past decade, the pathophysiology of this potentially life-threatening syndrome has been increasingly elucidated, large cohort studies have identified associated patient conditions and transfusion risk factors, and preventive strategies have been successfully implemented. These new insights provide a rationale for updating the 2004 consensus definition of TRALI.

STUDY DESIGN AND METHODS

An international expert panel used the Delphi methodology to develop a redefinition of TRALI by modifying and updating the 2004 definition. Additionally, the panel reviewed issues related to TRALI nomenclature, patient conditions associated with acute respiratory distress syndrome (ARDS) and TRALI, TRALI pathophysiology, and standardization of reporting of TRALI cases.

RESULTS

In the redefinition, the term "possible TRALI" has been dropped. The terminology of TRALI Type I (without an ARDS risk factor) and TRALI Type II (with an ARDS risk factor or with mild existing ARDS) is proposed. Cases with an ARDS risk factor that meet ARDS diagnostic criteria and where respiratory deterioration over the 12 hours before transfusion implicates the risk factor as causative should be classified as ARDS. TRALI remains a clinical diagnosis and does not require detection of cognate white blood cell antibodies.

CONCLUSIONS

Clinicians should report all cases of posttransfusion pulmonary edema to the transfusion service so that further investigation can allow for classification of such cases as TRALI (Type I or Type II), ARDS, transfusion-associated circulatory overload (TACO), or TRALI or TACO cannot distinguish or an alternate diagnosis.

TACO and TRALI: biology, risk factors, and prevention strategies

Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) are the leading causes of transfusion-related morbidity and mortality. These adverse events are characterized by acute pulmonary edema within 6 hours of a blood transfusion and have historically been difficult to study due to underrecognition and nonspecific diagnostic criteria. However, in the past decade, in vivo models and clinical studies utilizing active surveillance have advanced our understanding of their epidemiology and pathogenesis. With the adoption of mitigation strategies and patient blood management, the incidence of TRALI and TACO has decreased. Continued research to prevent and treat these severe cardiopulmonary events is focused on both the blood component and the transfusion recipient.

Association of Blood Transfusion From Female Donors With and Without a History of Pregnancy With Mortality Among Male and Female Transfusion Recipients

IMPORTANCE

Transfusion of red blood cells from female donors has been associated with increased mortality in male recipients.

OBJECTIVE

To quantify the association between red blood cell transfusion from female donors with and without a history of pregnancy and mortality of red blood cell recipients.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study of first-time transfusion recipients at 6 major Dutch hospitals enrolled from May 30, 2005, to September 1, 2015; the final follow-up date was September 1, 2015. The primary analysis was the no-donor-mixture cohort (ie, either all red blood cell transfusions exclusively from male donors, or all exclusively from female donors without a history of pregnancy, or all exclusively from female donors with a history of pregnancy). The association between mortality and exposure to transfusions from ever-pregnant or never-pregnant female donors was analyzed using life tables and time-varying Cox proportional hazards models.

EXPOSURES

Red blood cell transfusions from ever-pregnant or never-pregnant female donors, compared with red blood cell transfusions from male donors.

MAIN OUTCOMES AND MEASURES

All-cause mortality during follow-up.

RESULTS

The cohort for the primary analyses consisted of 31 118 patients (median age, 65 [interquartile range, 42-77] years; 52% female) who received 59 320 red blood cell transfusions exclusively from 1 of 3 types of donors (88% male; 6% ever-pregnant female; and 6% never-pregnant female). The number of deaths in this cohort was 3969 (13% mortality). For male recipients of red blood cell transfusions, all-cause mortality rates after a red blood cell transfusion from an ever-pregnant female donor vs male donor were 101 vs 80 deaths per 1000 person-years (time-dependent "per transfusion" hazard ratio [HR] for death, 1.13 [95% CI, 1.01-1.26]). For receipt of transfusion from a never-pregnant female donor vs male donor, mortality rates were 78 vs 80 deaths per 1000 person-years (HR, 0.93 [95% CI, 0.81-1.06]). Among female recipients of red blood cell transfusions, mortality rates for an ever-pregnant female donor vs male donor were 74 vs 62 per 1000 person-years (HR, 0.99 [95% CI, 0.87 to 1.13]); for a never-pregnant female donor vs male donor, mortality rates were 74 vs 62 per 1000 person-years (HR, 1.01 [95% CI, 0.88-1.15]).

CONCLUSIONS AND RELEVANCE

Among patients who received red blood cell transfusions, receipt of a transfusion from an ever-pregnant female donor, compared with a male donor, was associated with increased all-cause mortality among male recipients but not among female recipients. Transfusions from never-pregnant female donors were not associated with increased mortality among male or female recipients. Further research is needed to replicate these findings, determine their clinical significance, and identify the underlying mechanism.

Transfusion-related acute lung injury risk mitigation: an update

Transfusion-related acute lung injury (TRALI) is a life-threatening complication of transfusion. Greater understanding of the pathophysiology of this syndrome has much improved during the last two decades. Plasma-containing components from female donors with leucocyte antibodies were responsible for the majority of TRALI fatalities before mitigation strategies were implemented. Over the past 15 years, measures to mitigate risk for TRALI have been implemented worldwide and they continued to evolve with time. The AABB requires that all plasma containing components and whole blood for transfusion must be collected from men, women who have not been pregnant, or women who have tested negative for human leucocyte antigen antibodies. Although the incidence of TRALI has decreased following the institution of TRALI mitigation strategies, TRALI is still the most common cause of transfusion-associated death in the United States. In this review, we focus on TRALI risk mitigation strategies. We describe the measures taken by blood collection facilities to reduce the risk of TRALI in the United States, Canada and European countries. We also review the literature for the effectiveness of these measures.

Quality Assessment of Established and Emerging Blood Components for Transfusion

Blood is donated either as whole blood, with subsequent component processing, or through the use of apheresis devices that extract one or more components and return the rest of the donation to the donor. Blood component therapy supplanted whole blood transfusion in industrialized countries in the middle of the twentieth century and remains the standard of care for the majority of patients receiving a transfusion. Traditionally, blood has been processed into three main blood products: red blood cell concentrates; platelet concentrates; and transfusable plasma. Ensuring that these products are of high quality and that they deliver their intended benefits to patients throughout their shelf-life is a complex task. Further complexity has been added with the development of products stored under nonstandard conditions or subjected to additional manufacturing steps (e.g., cryopreserved platelets, irradiated red cells, and lyophilized plasma). Here we review established and emerging methodologies for assessing blood product quality and address controversies and uncertainties in this thriving and active field of investigation.

Effect of Blood Donor Characteristics on Transfusion Outcomes: A Systematic Review and Meta-Analysis

Optimal selection of blood donors is critical for ensuring the safety of blood products. The current selection process is concerned principally with the safety of the blood donor at the time of donation and of the recipient at the time of transfusion. Recent evidence suggests that the characteristics of the donor may affect short- and long-term transfusion outcomes for the transfused recipient. We conducted a systematic review with the primary objective of assessing the association between blood donor characteristics and red blood cell (RBC) transfusion outcomes. We searched MEDLINE, EMBASE, and Cochrane Central databases and performed manual searches of top transfusion journals for all available prospective and retrospective studies. We described study characteristics, methodological quality, and risk of bias and provided study-level effect estimates and, when appropriate, pooled estimates with 95% confidence intervals using the Mantel-Haenszel or inverse variance approach. The overall quality of the evidence was graded using Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. From 6121 citations identified by our literature search, 59 studies met our eligibility criteria (50 observational, 9 interventional). We identified the evaluation of association of 17 donor characteristics on RBC transfusion outcome. The risk of bias and confounding of the included studies was high. The quality of evidence was graded as very low to low for all 17 donor characteristics. Potential associations were observed for donor sex with reduced survival at 90 days and 6 months in male recipients that receive donated blood from females (hazard ratio 2.60 [1.09, 6.20] and hazard ratio 2.40 [1.10, 5.24], respectively; n = 1), Human Leukocyte Antigen - antigen D Related (HLA-DR) selected transfusions (odds ratio [OR] 0.39 [0.15, 0.99] for the risk of transplant alloimmunization, n = 9), presence of antileukocyte antibodies (OR 5.84 [1.66, 20.59] for risk of transfusion-related acute lung injury, n = 4), and donor RBC antigens selection (OR 0.20 [0.08, 0.52] for risk of alloimmunization, n = 4). Based on poor quality evidence, positive antileukocyte antibodies, female donor to male recipients, HLA-DR selected RBC transfusion, or donor RBC antigen selection may affect RBC transfusion outcome. Our findings that donor characteristics may be associated with transfusion outcomes warrant establishing vein-to-vein data infrastructure to allow for large robust evaluations. PROSPERO registration number: CRD42013006726.

Transfusion-related acute lung injury in paediatric surgical patients: a retrospective study

BACKGROUND

Little is known about the occurrence of transfusion-related acute lung injury(TRALI) in Chinese paediatric patients. As such, a retrospective review of medical records from January 2008 to December 2011 was undertaken.

OBJECTIVE

To determine the incidence of TRALI and its risk factors in children (age <14 years).

STUDY DESIGN AND METHODS

All medical records of Sheng Jing Hospital from January 2008 to December 2011 were reviewed retrospectively using the hospital’s record system. Paediatric surgical patients who had been diagnosed clinically with acute lung injury were included. Transfusion data were collected, together with risk factors such as sepsis and aspiration.

RESULTS

In total, 1495 patients were involved in the study. Thirty-five cases were analysed further as they had acute lung injury, pulmonary oedema and respiratory distress. TRALI was confirmed in two of these cases. The average duration of transfusion was found to be significantly longer in patients with TRALI compared with controls, and the percentage of female donors was significantly higher for patients with TRALI.

CONCLUSION

The incidence of TRALI was found to be lower than reported previously, but TRALI is under-recognised, under-reported and undertreated.

Transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is defined as the onset or the worsening of respiratory distress within 6  h of the transfusion of a plasma-containing blood component. It is currently considered to be one of the leading causes of severe posttransfusion morbidity and acute mortality in countries with a high development index. Understanding of the pathogenesis of TRALI has resulted in the development of preventive measures that have contributed to reducing its incidence. Early recognition of the clinical symptoms allow the clinician to identify the syndrome and to undertake therapeutic measures that may reduce the morbidity and mortality associated with this complication.

Split Blood Products

The last 20 years have seen many advances in transfusion therapy and safety. Blood products are biological products engendering complex interactions with the immune system. Prestorage leukoreduction results in a reduced risk of febrile reactions, CMV transmission, and immune modulation, proving to be safer for patients than non-leuko reduced products.

Simple patient identification issues and clerical error continue to be the primary causes of ABO-incompatible transfusions. Rigorous donor screening as well as serologic and nucleic acid testing for transfusion transmitted infection have brought the blood supply to a very safe level, although transmission of these agents continues to be a problem in underdeveloped countries. Emerging infectious diseases, beyond current laboratory detection capabilities, combined with global travel, pose unknown imminent risks everywhere. We also briefly discuss the current risks of transfusion-transmitted infections.

We review currently available hemostatic blood products, their compositions, and their clinical indications; we mention product modifications currently in development; and we touch upon the hemostatic properties and drawbacks of whole blood, which is currently gaining popularity as an alternative to split blood products. We conclude with an in-depth overview of the risks associated with transfusion, including incompatibility, hemolytic transfusion reactions, transfusion-associated circulatory overload (TACO), and transfusion-related acute lung injury (TRALI).

Analysis of leucocyte antibodies, cytokines, lysophospholipids and cell microparticles in blood components implicated in post-transfusion reactions with dyspnoea

BACKGROUND AND OBJECTIVES

Post-transfusion reactions with dyspnoea (PTR) are major causes of morbidity and death after blood transfusion. Transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) are most dangerous, while transfusion-associated dyspnoea (TAD) is a milder respiratory distress. We investigated blood components for immune and non-immune factors implicated in PTR.

MATERIAL AND METHODS

We analysed 464 blood components (RBCs, PLTs, L-PLTs, FFP) transfused to 271 patients with PTR. Blood components were evaluated for 1/antileucocyte antibodies, 2/cytokines: IL-1β, IL-6, IL-8, TNF-α, sCD40L, 3/lysophosphatidylcholines (LysoPCs), 4/microparticles (MPs) shed from plateletes (PMPs), erythrocytes (EMPs) and leucocytes (LMPs).

RESULTS

Anti-HLA class I/II antibodies or granulocyte-reactive anti-HLA antibodies were detected in 18.2% of blood components (RBC and FFP) transfused to TRALI and in 0.5% of FFP transfused to TAD cases. Cytokines and LysoPCs concentrations in blood components transfused to PTR patients did not exceed those in blood components transfused to patients with no PTR. Only EMPs percentage in RBCs transfused to patients with TRALI was significantly higher (P < 0.05) than in RBCs transfused to patients with no PTR.

CONCLUSION

Immune character of PTR was confirmed mainly in 1/5 TRALI cases. Among non-immune factors, only MPs released from stored RBCs are suggested as potential mediators of TRALI. Our results require further observations in a more numerous and better defined group of patients.

Transfusion-related acute lung injury: advances in understanding the role of proinflammatory mediators in its genesis

Transfusion-related acute lung injury (TRALI) is the most common cause of serious morbidity and mortality due to hemotherapy. The pathogenesis is the result of two events: the first related to the recipient's clinical condition, predisposing to acute lung injury (ALI) through neutrophil or polymorphonuclear leukocyte sequestration, and the second being the infusion of antibodies or mediators that activate these adherent polymorphonuclear neutrophils, resulting in endothelial damage, capillary leak and ALI. TRALI is most prevalent in the critically ill, although many of these cases are termed ALI. Although mitigation strategies, such as the use of male-only plasma, have decreased the number of TRALI cases and deaths, TRALI still occurs. This review will detail the pathophysiology of TRALI, provide insight into newer areas of research and critically assess current practices to mitigate TRALI and improve transfusion safety.

Transfusion-related lung injury in children: a case series and review of the literature

BACKGROUND

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related mortality. The majority of the literature involves adult patients. The main objective of this study was to characterize the demographic features, clinical presentation, patient outcomes, and antibody profiles of TRALI patients reported to the Canadian Blood Service (CBS) and to assess similarities and differences between adult and pediatric TRALI cases.

STUDY DESIGN AND METHODS

A retrospective review of cases of TRALI submitted to the CBS from 2001 to 2011 was performed. Information collected included recipient demographics, event details, blood component transfused, morbidity and mortality data, and donor antibody results.

RESULTS

A total of 284 cases of definite, possible, or probable TRALI were reported. Six percent (n = 17) occurred in children. There were no significant differences between pediatric or adult patients with TRALI. Most of the children who presented with TRALI were either teenagers or less than 1 year of age. The incident rate of reported TRALI cases in Canada per 100,000 red blood cell transfusions was estimated at 5.58 for children and 3.75 for adults.

CONCLUSIONS

This study is the largest case series of reported TRALI cases in children. Crude modeling suggests that the incidence of TRALI in children is similar to that of adults. Although the numbers are small, there do not appear to be differences in presentation or outcome between adults and children with TRALI. TRALI is associated with significant morbidity and mortality and pediatricians need to consider this diagnosis in children who experience respiratory distress after transfusions.

Inhibition of lysophosphatidic acid increase by prestorage whole blood leukoreduction in autologous CPDA-1 whole blood

BACKGROUND

Lysophosphatidylcholine (LPC) has been implicated in the onset of transfusion-related acute lung injury (TRALI). In plasma, LPC is converted to lysophosphatidic acid (LPA) by autotaxin (ATX). The effect of leukoreduction in the accumulation of these bioactive lipids and ATX in human autologous blood has not been fully investigated.

STUDY DESIGN AND METHODS

The accumulation of choline-containing phospholipids (LPC, sphingomyelin [SM], and phosphatidylcholine [PC]), LPA, and ATX during the storage of autologous blood and the changes caused by leukoreduction were investigated. A total of 26 orthopedic patients were enrolled. Autologous blood was collected as whole blood and, after leukoreduction, preserved refrigerated until use. Prestorage leukoreduced (LR) and non-LR autologous blood samples were analyzed. The time-dependent changes and the effect of the filtration were compared.

RESULTS

A time-dependent and significant increase in the levels of LPA was observed in both non-LR and LR samples. The concentration of LPA was significantly reduced in LR compared to non-LR samples. The concentration of LPC was higher in LR compared to non-LR samples. The levels of PC, SM, and ATX were not affected by either the storage period or the leukoreduction.

CONCLUSIONS

Leukoreduction of autologous whole blood effectively reduced the accumulation of LPA. On the other hand, prestorage leukoreduction resulted in an increased concentration of LPC, without significantly affecting ATX. Further studies are necessary to confirm the role of LPA in the pathogenesis of adverse effects of blood transfusion, especially TRALI.

Frozen blood products: clinically effective and potentially ideal for remote Australia

The development of effective cryopreservation techniques for both red blood cells and platelets, which maintain ex vivo biological activity, in combination with frozen plasma, provides for a unique blood banking strategy. This technology greatly enhances the storage life of these products. The rationale and potential advantages of using cryopreservation techniques for the provision of blood products to remote and military environments have been effectively demonstrated in several conflicts over the last decade. Current haemostatic resuscitation doctrine for the exsanguinating patient supports the use of red blood cells, platelets and frozen plasma early in the resuscitation. We believe an integrated fresh-frozen blood bank inventory could facilitate provision of blood products, not only in the military setting but also in regional Australia, by overcoming many logistic and geographical challenges. The processes involved in production and point of care thawing are sufficiently well developed and achievable to make this technology a viable option. The potential limitations of cryopreservation and subsequent product thawing need to be considered if such a strategy is to be developed. A substantial body of international experience using cryopreserved products in remote settings has already been accrued. This experience provides a template for the possible creation of an Australian integrated fresh-frozen blood bank inventory that could conceivably enhance the care of patients in both regional Australia and in the military setting.

Transfusion-related acute lung injury: a preventable syndrome?

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Recent insights into the pathophysiology of TRALI have led to various preventive strategies. Strategies in donor management range from antibody testing of sensitized donors to the deferral of female plasma donors altogether. However, knowledge on the efficacy of measures to reduce TRALI is limited. In addition, the various measures may lead to a substantial loss of donors, hampering steady blood supply. Thereby, consensus among countries and blood-collecting facilities regarding the optimal strategy to prevent TRALI is lacking. In this review, the advantages and disadvantages of various preventive measures to prevent TRALI are discussed, related to both patient factors as well as blood component-processing strategies, including transfusion policy, donor management and practices of preparation and storage conditions of blood components.

A threshold model for the susceptibility to transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is a serious, often life-threatening pulmonary transfusion reaction characterized by non-cardiogenic lung oedema, hypoxemia and respiratory distress in temporal association with blood transfusion. The critical mechanism in TRALI is the sudden increase in permeability of the pulmonary endothelium and the subsequent, often extensive shift of fluid into the alveolae. The rapid clinical recovery seen in most patients makes it likely that this is a temporary phenomenon. Reactive oxygen species released by neutrophils or other cells are attractive candidate mediators of this process. There is experimental and clinical evidence that several pathways can induce barrier breakdown in TRALI, a concept known as the threshold model of TRALI. Surprisingly, neutrophils may not always be required. Other cells may play a role as multipliers or attenuators of TRALI, depending on recipient-related and transfusion-related factors involved. This review will summarize recent findings on pathophysiology, with a focus on newly discovered or disenchanted recipient-related and transfusion-related risk factors for TRALI and will present the threshold model of TRALI as a unifying concept on how TRALI develops.

High concentration plasma-reduced plateletapheresis concentrates

Single-donor hyperconcentrated plateletapheresis (dry-platelets) collection has been introduced in the 90's as a part of the newly developed multi-component collection strategy. This approach allowed to safely collect multiple components from a single apheresis donation, i.e. RBC, FFP and/or plateletpheresis units. Dry-platelets are usually resuspended in additive solution to maintain an adequate pH during the storage period until use. Some concern existed about possible higher degrees of platelet activation in dry-platelets units when compared to standard concentration (1.0-1.6 × 10(6)/μL platelets) units and its possible correlation with lower in vivo efficiency and/or survival of the former units. Several authors investigated this specific issue, and dry-platelets units proved to be equally effective than standard concentration plateletpheresis units in recipients. The use of dry-platelets units may reduce (i) the risk of passive infusion of naturally occurring ABO-related hemolytic antibodies when donor O platelets are given to group A, B, or AB recipient, (ii) the risk of TRALI when multiparous donors undergo plateletpheresis. Furthermore, dry-platelet collection may allow for an increased amount of FFP sent to industry. Finally, hyperconcentrated platelet units may be used for "niche" indications, such as intrauterine platelet transfusion or, in case of autologous dry-platelet collection, for further freezing for long term storage in selected patients within onco-hematological settings.

Alloexposed blood donors and transfusion-related acute lung injury: a case-referent study

BACKGROUND

Donor white blood cell (WBC) antibodies are thought to increase the risk of transfusion-related acute lung injury (TRALI). WBC antibodies can be present in blood products from donors who have been alloexposed. Alloexposed donors are increasingly excluded from donating plasma, but can still donate plasma-poor products. We aimed to quantify the contribution of alloexposed donors to the occurrence of TRALI for different blood product types.

STUDY DESIGN AND METHODS

We performed a case-referent study including all reported TRALI patients and all Dutch blood donors. Data on alloexposure status of donors of all TRALI cases reported between January 2004 and October 2008, in the Netherlands, were compared to information on the total donor population.

RESULTS

Alloexposure status of all 223 involved donors was compared to the expected status. The overall percentage of TRALI cases that could have been prevented by the deferral of all alloexposed donors (i.e., population-attributable risk [PAR]) was 51% (95% confidence interval [CI], 14%-88%). In 19 recipients of exclusively plasma-poor products (mostly red blood cells [RBCs]), alloexposure of the donors was not associated with TRALI, while in 28 recipients of both plasma-poor and plasma-rich products (>200 mL plasma), the PAR was 94% (95% CI, 34%-100%).

CONCLUSIONS

Alloexposed donors conferred an increased risk of TRALI in recipients of plasma-rich products, but not in recipients of plasma-poor products. Although WBC antibodies are an important risk factor for TRALI, among RBC recipients another risk factor must be more important.