How much residual plasma may cause TRALI?

Separation of platelets by size in a microfluidic device based on controlled incremental filtration

The significant biological and functional differences between small and large platelets suggested by recent studies could have profound implications for transfusion medicine. However, investigating the relationship between platelet size and function is challenging because separating platelets by size without affecting their properties is difficult. A standard approach is centrifugation, but it inevitably leads to premature activation and aggregation of separated platelets. This paper describes the development and validation of a microfluidic device based on controlled incremental filtration (CIF) for separating platelets by size without the cell damage and usability limitations associated with centrifugation. Platelet samples derived from whole blood were used to evaluate the dependence of the CIF device separation performance on design parameters and flow rate, and to compare the properties of PLT fractions generated by the CIF device with those produced using a centrifugation protocol in a split-sample study. This was accomplished by quantifying the platelet size distribution, mean platelet volume (MPV), platelet-large cell ratio (P-LCR) and platelet activation before and after processing for all input and output samples. The 'large platelet' fractions produced by the CIF device and the centrifugation protocol were essentially equivalent (no significant difference in MPV and P-LCR). Platelets in the 'small platelet' fraction produced by the CIF device were significantly smaller than those produced by centrifugation (lower MPV and P-LCR). This was because the CIF 'small platelet' fraction was contaminated by much fewer large platelets (∼2-times lower recovery of >12 fL platelets) and retained the smallest platelets that were discarded by the centrifugation protocol. There was no significant difference in platelet activation between the two methods. However, centrifugation required a substantial amount of additional anticoagulant to prevent platelet aggregation during pelleting. Unlike centrifugation, the CIF device offered continuous, flow-through, single-step processing that did not cause platelet aggregation. Such a capability has the potential to accelerate the basic studies of the relationship between platelet size and function, and ultimately improve transfusion practice, particularly in the pediatric setting, where the need for low-volume, high-quality platelet transfusions is most urgent.

Donor-recipient sex is associated with transfusion-related outcomes in critically ill patients

Transfusion of female RBCs to male recipients increases the risk of ICU mortality compared with female blood to female recipients.

Receiving RBCs from female donors is associated with a trend toward ARDS.

Transfusion of red blood cells (RBCs) from female donors has been associated with increased risk of mortality. This study aims to investigate the associations between donor-recipient sex and posttransfusion mortality and morbidity in critically ill patients who received RBC transfusions from either male-only donors or from female-only donors (unisex-transfusion cases). Survival analysis was used to compare 4 groups: female-to-female, female-to-male, male-to-female, and male-to-male transfusion. Multivariate logistic model was used to evaluate the association between donor sex and intensive care unit (ICU) mortality. Associations between transfusion and acute kidney injury (AKI), acute respiratory distress syndrome (ARDS), and nosocomial infections were assessed. Of the 6992 patients included in the original cohort study, 403 patients received unisex-transfusion. Survival analysis and the logistic model showed that transfusion of female RBCs to male patients was associated with an increased ICU mortality compared with transfusion of female RBCs to female patients (odds ratio, 2.43; 95% confidence interval, 1.02-5.77; P < .05). There was a trend toward increased ARDS in patients receiving RBC from female donors compared with those receiving blood from males (P = .06), whereas AKI was higher in donor-recipient sex-matched transfusion groups compared with sex-mismatched groups (P = .05). This was an exploratory study with potential uncontrolled confounders that limits broad generalization of the findings. Results warrant further studies investigating biological mechanisms underlying the association between donor sex with adverse outcomes as well as studies on the benefit of matching of blood between donor and recipient.

Cryopreserved buffy-coat-derived platelets reconstituted in platelet additive solution: A safe and available product with sufficient haemostatic effectiveness

BACKGROUND

Platelets (PLTs) stored at 20-24 °C have a short shelf life of only 5 days, which can result in their restricted availability. PLT cryopreservation extends the shelf life to 2 years.

METHODS

We implemented a method of PLT freezing at -80 °C in 5-6% dimethyl sulfoxide. Buffy-coat-derived leucodepleted fresh PLTs blood group O (FP) were used for cryopreservation. Cryopreserved pooled leucodepleted PLTs (CPP) were thawed at 37 °C, reconstituted in PLT additive solution SSP + and compared to FP regarding PLT content, PLT concentration, pH, volume, PLT loss, anti-A/B antibody titre, total protein, plasma content, and PLT swirling. Clot properties were evaluated via rotational thromboelastometry. PLT microparticle number and surface receptor phenotype were assessed via flow cytometry.

RESULTS

CPP met the required quality parameters. The mean freeze-thaw PLT loss was 22.24 %. Anti-A/B antibody titre and plasma content were significantly lower in CPP. CPP were characterised by faster clot initiation and form stable PLT clots. The number of PLT microparticles increased 25 times in CPP and there were more particles positive for the activation marker CD62 P compared to FP.

CONCLUSION

Thawing and reconstitution are easy and fast processes if platelet additive solution is used. Low anti-A/B antibody titre and plasma content make possible the use of CPP of blood group O reconstituted in SSP + as universal ABO products, including clinical situations where washed PLTs are required. Clot properties evaluated via rotational thromboelastometry demonstrated that CPP retain a significant part of their activity compare to FP and are haemostatically effective.

Leukocyte-Reactive Antibodies in Female Blood Donors: The Austrian Experience

Introduction

Antibody-mediated transfusion-related acute lung injury (TRALI) is caused by antibodies against human leukocyte antigens (HLAs) or human neutrophil antigens (HNAs), and is one of the most serious complications associated with transfusion medicine. Prevention strategies like testing allo-exposed female blood donors have not yet been introduced nationwide in Austria. To assess the need and feasibility of routine leukocyte antibody testing, the prevalence of leukocyte-reactive antibodies in an Austrian female donor population was been determined using classical cell-based methods which were compared with a high-throughput bead-based method.

Methods

Sera from 1,022 female blood donors were screened using a granulocyte aggregation test (GAT) and a white blood cell immunofluorescence test (WIFT) after retesting and specification of positive samples by granulocyte immunofluorescence test (GIFT) and monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA). Potential HLA reactivities were confirmed using the microbeads assay LabScreen^TM Mixed. The results in 142 donor sera and 38 well-defined reference sera were investigated by the microbeads assay LabScreen^TM Multi and compared with classical cell-based methods.

Results

Reactivity with either granulocytes and/or lymphocytes was detected in 79 sera (7.7%), with the majority being HLA-specific. Antibodies against HNA were obtained in 7 samples (0.7%). The aggregating potential of the detected antibodies was observed in 9 cases (0.9%). Most of the leukocyte-reactive antibodies occurred at a donor age of between 35 and 59 years (n = 61). LabScreen Multi showed good agreement (κ = 0.767) for HNA antibody detection by cell-based assays, but double/multiple specificities (100% of 7 anti-HNA-1b sera) as well as false-negative results (40% of 15 HNA-3-specific sera) occurred.

Discussion

Leukocyte-reactive antibody screening is advised in Austrian female donors for safe blood transfusion, including single-donor convalescent plasma treatment of COVID-19 that may be implemented soon. For the introduction of LabScreen Multi, the combination with GAT should be considered to ensure correct anti-HNA-3a detection.

Granulocyte antibodies in male blood donors: can they trigger transfusion-related acute lung injury?

BACKGROUND

White blood cell-associated antibodies can lead to transfusion-related acute lung injury (TRALI). Female donors with a history of pregnancies have been identified as a main cause for these antibodies. Male or female donors without a history of pregnancy are considered as safe donors.

STUDY DESIGN AND METHODS

Following the identification of two TRALI cases associated with blood products from male donors, we investigated the frequency of granulocyte-specific and human leukocyte antigen (HLA) antibodies in the entire blood donor population using a high throughput automated flow-cytometry-based granulocyte immunofluorescence test (Flow-GIFT). We investigated sera from 14,343 whole blood donors (female, n = 6974, 48.7%; male, n = 7369, 51.3%) using automated Flow-GIFT. Of the female blood donors, 60.4% had a history of pregnancy. Positive sera were retested by the standard granulocyte immunofluorescence test and granulocyte agglutination test. For the detection of HLA Class I and II immunoglobulin G antibodies, we used a commercial screening enzyme-linked immunosorbent assay.

RESULTS

We detected in 924 (21.9%) of the 4212 females with a history of pregnancy antibodies against granulocyte antigens (n = 62, 1.5%), HLA Class I and/or II antigens (n = 864, 20.5%). Notably, in 3.5% (n = 96) of 2762 females without a history of pregnancy and in 2.1% (n = 154) of 7369 males antibodies against granulocyte antigens (n = 13, 0.47% and n = 45, 0.6%), HLA Class I and/or II (n = 83, 3% and n = 109, 1.4%, respectively), were also detected.

CONCLUSION

Human neutrophil antigen antibodies are rare in male and females without a history of pregnancy compared to females with a history of pregnancy, but their relevance is not negligible.

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.

The accumulation of lipids and proteins during red blood cell storage: the roles of leucoreduction and experimental filtration

Pre-storage leucoreduction has been universally adopted in most developed countries in Asia, Europe and the Americas. It decreases febrile transfusion reactions, alloimmunisation to HLA antigens, cytomegalovirus exposure, the accumulation of a number of pro-inflammatory mediators in the supernatant, including the accumulation of platelet-and leucocyte-derived proteins and metabolites during routine storage. This review will highlight the lipids and proteins, biological response modifiers (BRMs) that accumulate, their clinical effects in transfused hosts, and methods of mitigation.

Determining the Volume of Additive Solution and Residual Plasma in Whole Blood Filtered and Buffy Coat Processed Red Cell Concentrates

BACKGROUND

Residual plasma in transfused red cell concentrates (RCCs) has been associated with adverse transfusion outcomes. Despite this, there is no consensus on the standard procedure for measuring residual plasma volume.

METHODS

The volumes of residual plasma and additive solution were measured in RCCs processed using two separation methods: whole blood filtration (WBF) and buffy coat (BC)/RCC filtration. The concentration of mannitol and albumin in RCC components was measured using colorimetric assays. Mannitol concentration was used to calculate additive solution volume. Residual plasma volume was calculated using two methods.

RESULTS

Calculated RCC supernatant volumes were much lower in BC-processed components compared to WBF-processed components (BC = 97 ± 6 ml, WBF = 109 ± 4 ml; p < 0.05). Calculated additive solution volumes were greater in WBF- than in BC-processed components (BC = 81 ± 4 ml, WBF = 105 ± 2 ml; p < 0.05). Absolute residual plasma volume varied significantly based on the calculation method used.

CONCLUSION

Disparity between plasma volume calculation methods was observed. Efforts should be made to standardize residual plasma volume measurement methods in order to accurately assess the impact of residual plasma on transfusion outcomes.

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.

Antibody-mediated transfusion-related acute lung injury; from discovery to prevention

Transfusion-related acute lung injury (TRALI), a syndrome of respiratory distress caused by blood transfusion, is the leading cause of transfusion-related mortality. The majority of TRALI cases have been related to passive infusion of human leucocyte antigen (HLA) and human neutrophil antigen (HNA) antibodies in donor blood. In vitro, ex vivo and in vivo animal models have provided insight in TRALI pathogenesis. The various classes of antibodies implicated in TRALI appear to have different pathophysiological mechanisms for the induction of TRALI involving endothelial cells, neutrophils, monocytes and, as very recently has been discovered, lymphocytes. The HLA and HNA-antibodies are found mainly in blood from multiparous women as they have become sensitized during pregnancy. The incidence of TRALI has decreased rapidly following the introduction of a male-only strategy for plasma donation. This review focuses on pre-clinical and clinical studies investigating the pathophysiology of antibody-mediated TRALI.

Residual plasma in red blood cells and transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is the most common cause of death from blood transfusion and red blood cells (RBCs) now account for approximately 50% of these fatalities. RBCs from female donors have been implicated in large series and HLA Class II antibodies to cognate recipient antigens identified in small series and case reports. The absolute volume of residual plasma in these RBCs is unknown.

STUDY DESIGN AND METHODS

Two confirmed cases of RBC-associated TRALI in which the implicated donors had Class II antibodies were investigated, and the antibody strength against recipient cognate antigens was assessed using a fluorescent bead assay. RBCs in additive solution (AS) were studied on Day 42 of liquid storage to calculate residual anticoagulated plasma.

RESULTS

Both RBC units were stored in AS-1 and were from female donors who had anti-HLA Class II antibodies of high strength against cognate antigens in the recipients. Anti-DR4 was identified in both cases. Nineteen AS-1 RBC units manufactured from whole blood donations using a hard spin had a mean (±1SD) residual plasma content of 38 ± 8 mL, and 26 AS-3 RBC units manufactured using a soft spin had 66 ± 13 mL (p < 0.01).

CONCLUSION

RBCs continue to be manufactured from female donors of unknown or even known anti-HLA status. The residual plasma content of these RBCs may approach 100 mL. A combination of a high-strength antibody and large residual plasma volume could explain severe or even fatal RBC-associated TRALI.

[Acute lung injury as a consequence of fresh frozen plasma administration in a patient with factor XII deficiency]

Along with the complete blood count, the coagulation tests are those most demanded before a surgical procedure. The activated partial thromboplastin time (APPT) quantifies the intrinsic and common coagulation pathways, including factors XII, XI, IX, VIII, X, V and II. Factor XII deficiency is associated with a prolonged APPT and an increase in thromboembolic phenomena, without increasing the intraoperative bleeding risk. A 20 year old man with factor XII deficiency was receiving two units of fresh frozen plasma because of an APPT of 100 seconds, with the intention of normalizing it before an urgent surgery procedure, and the fear of intraoperative bleeding. An hour after starting the transfusion the patient developed an acute lung injury (ALI) compatible with the diagnosis of a transfusion related acute lung injury (TRALI). The surgery continued without complications, and the patient was admitted to the resuscitation unit for 72 h, needing respiratory support. If the APTT is prolonged in the absence of bleeding, the presence of a non-specific circulating anticoagulant, a deficiency of factor XI, XII and VIII (associated to Von Willebrand disease) must be ruled out. Therefore, in the case presented here, the administration of hemoderivatives was unnecessary and can have consequences as serious as the one that the patient presented, a transfusion related acute lung injury.

The impact of platelet additive solution apheresis platelets on allergic transfusion reactions and corrected count increment (CME)

BACKGROUND

Allergic transfusion reaction (ATR) incidence ranges from 1% to 3% of all transfusions. We evaluated the impact of InterSol platelet additive solution (PAS) apheresis platelets (APs) on the incidence of ATRs and the posttransfusion platelet (PLT) increment.

STUDY DESIGN AND METHODS

This retrospective study evaluated all ATRs among patients at a university hospital that maintained a mixed inventory of PAS APs and non-PAS APs (standard plasma-suspended PLTs). Corrected count increments (CCIs) were calculated for AP transfusions of individuals who received both a PAS and a non-PAS AP transfusion within a 7-day period. Hypothesis testing was performed with chi-square test for dichotomous variables and t tests for continuous variables.

RESULTS

The incidence of ATRs among the non-PAS APs was 1.85% (72 ATRs/3884 transfusions) and 1.01% (12 ATRs/1194 transfusions) for PAS APs (risk ratio [RR], 0.54; 95% confidence interval [CI]=0.30-0.99; p=0.04). However, there was no difference in the incidence of febrile nonhemolytic transfusion reactions between non-PAS APs (incidence, 0.70%; 27/3884) compared to PAS APs (incidence, 0.59%; 7/1194; p=0.69). Among 223 individuals with paired non-PAS and PAS AP transfusions, the mean CCI at 1 to 4 hours after transfusion was 4932 (95% CI, 4452-5412) for non-PAS APs and was lower for PAS APs (CCI, 3766; 95% CI, 3375-4158; p ≤ 0.001). However, there was no significant difference in mean CCI at 12 to 24 hours between non-PAS (CCI, 2135; 95% CI, 1696-2573) and PAS APs (CCI, 1745; 95% CI, 1272-2217; p=0.14).

CONCLUSIONS

PAS APs substantially reduce the number of ATRs. CCIs for PAS APs were lower immediately after transfusion, but not significantly different at 12 to 24 hours.

[Transfusion-related acute lung injury]

Transfusion-related acute lung injury (TRALI) developed into the leading cause of transfusion-related morbidity and mortality after the first description by Popovsky et al. approximately three decades ago. It was the most frequent reason for transfusion-related fatalities worldwide before implementation of risk minimization strategies by donor selection. Plasma-rich blood products, such as fresh frozen plasma and apheresis platelets seem to be the leading triggers of TRALI. Hypoxemia and development of pulmonary edema within 6 h of transfusion are the diagnostic criteria for TRALI. The differentiation between cardiac failure and other transfusion-related lung injuries, such astransfusion-associated circulatory overload ( TACO) is difficult and causal treatment is not available. Therapy is based on supportive measures, such as oxygen insufflationor mechanical ventilation. The exactly pathogenesis is still unknown but the most propagated hypothesis is the two-event-model. Neutrophils are primed by the underlying condition, e.g. sepsis or trauma during the first event and these primed neutrophils are activated by transfused leukoagglutinating antibodies (immunogen) or bioreactive mediators (non-immunogen) during the second-event. Transfusion of leukoagglutinating antibodies from female donors with one or more previous pregnancies is the most frequent reason. No more TRALI fatalities were reported after implementation of the donor selection in Germany in 2009.

Transfusion-related acute lung injury: a clinical review

Three decades ago, transfusion-related acute lung injury (TRALI) was considered a rare complication of transfusion medicine. Nowadays, the US Food and Drug Administration acknowledge the syndrome as the leading cause of transfusion-related mortality. Understanding of the pathogenesis of TRALI has resulted in the design of preventive strategies from a blood-bank perspective. A major breakthrough in efforts to reduce the incidence of TRALI has been to exclude female donors of products with high plasma volume, resulting in a decrease of roughly two-thirds in incidence. However, this strategy has not completely eradicated the complication. In the past few years, research has identified patient-related risk factors for the onset of TRALI, which have empowered physicians to take an individualised approach to patients who need transfusion.

Immune-reactive soluble OX40 ligand, soluble CD40 ligand, and interleukin-27 are simultaneously oversecreted in platelet components associated with acute transfusion reactions

BACKGROUND

Leukoreduction of labile blood components dramatically decreases the frequency of minor, intermediate, and severe adverse events (AEs), referred to as acute transfusion reactions (ATRs), especially after transfusion of platelet components (PCs). The pathophysiology of AEs may result from accumulation of soluble, secreted, platelet (PLT) factors with proinflammatory functions stored in PCs. Thus, several cosynergizing factors associated with PLT accumulation in PCs may contribute to clinically reported ATRs with inflammatory symptoms.

STUDY DESIGN AND METHODS

We screened for 65 PLT-associated secretory products in PCs that caused ATRs and identified PLT molecules associated with ATRs and inflammation. A functional in vitro study using PC supernatants assayed on reporting immune cells was performed to indicate relevance.

RESULTS

Among 10,600 apheresis PCs, 30 caused inflammatory ATRs and contained significantly elevated levels of soluble CD40 ligand (sCD40L), interleukin (IL)-27, and soluble OX40 ligand (sOX40L). Normal PLTs secreted IL-27 and sOX40L at bioactive concentrations upon thrombin stimulation and were up regulated in association with ATRs, similar to sCD40L. Other secreted products were identified but not investigated further as their positivity was not consistent.

CONCLUSIONS

This study demonstrates the putative participation of PLT-derived sOX40L, IL-27, and sCD40L, which accumulate in PC supernatants, with inflammatory-type ATRs. Further studies are required to determine the clinical significance of these findings to forecast preventive measures whenever possible.

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.

Mechanical ventilation and the titer of antibodies as risk factors for the development of transfusion-related lung injury

Purpose. Onset of transfusion-related acute lung injury (TRALI) is suggested to be a threshold-event. Data is lacking on the relation between titer of antibodies infused and onset of TRALI. We determined whether onset of TRALI is dependent on the titer of MHC-I antibodies infused in a combined model of ventilator-induced lung injury and antibody-induced TRALl. Methods. BALB/c mice were ventilated for five hours with low (7.5 ml/kg) or high (15 ml/kg) tidal volume. After three hours of MV, TRALI was induced by infusion of 0.5 mg/kg, 2.0 mg/kg or 4.5 mg/kg MHC-I antibodies. Control animals received vehicle. After five hours of MV, animals were sacrificed. Results. MV with high tidal volumes resulted in increased levels of all markers of lung injury compared to animals ventilated with low tidal MV. In ventilator-induced lung injury, infusion of 4.5 mg/kg of antibodies further increased pulmonary wet-to-dry ratio, pulmonary neutrophil influx and pulmonary KC levels, whereas infusion of lower dose of antibodies did not augment lung injury. In contrast, mice ventilated with low tidal volumes did not develop lung injury, irrespective of the dose of antibody used. Conclusions. In the presence of injurious MV, onset of TRALI depends on the titer of antibodies infused.

Implementation and outcomes of a transfusion-related acute lung injury surveillance programme and study of HLA/HNA alloimmunisation in blood donors

BACKGROUND

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-associated mortality. Antibodies against human leucocyte antigens (HLA) and human neutrophil antigens (HNA) are often detected in the implicated donors. We investigated the incidence and aetiology of TRALI in Lombardy. Moreover, we determined the rate of HLA and HNA alloimmunisation and the HNA genotype in a cohort of local blood donors.

MATERIALS AND METHODS

During a 2-year observational study in eight blood transfusion services, suspected TRALI cases were collected and characterised by means of HLA and HNA antibody screening of implicated donors, donor/recipient cross-matching and HLA/HNA molecular typing. In addition, 406 Italian donors were evaluated for alloimmunisation and in 102 of them HNA gene frequencies were determined.

RESULTS

Eleven cases were referred to the central laboratory, of whom three were diagnosed as having TRALI, seven as having possible TRALI and one as having transfusion-associated circulatory overload. Seven TRALI cases were immune-mediated whereas in three we did not find either alloantibodies in implicated donors or a positive reaction in the cross-match. The most frequently implicated blood component was red blood cells (in 5 males and in 1 female), whereas four cases of TRALI were associated with transfusion of fresh-frozen plasma (in 3 females and in 1 male). The frequency of reported TRALI/possible TRALI cases was 1:82,000 for red blood cells and 1:22,500 for fresh-frozen plasma. No cases were observed for platelets. Overall, the frequency of HLA or HNA alloimmunisation in blood donors was 29% for females and 7% for males. The latter could be related, at least in part, to natural antibodies. HNA gene frequencies showed that HNA-1b is more frequent than HNA-1a in our sample of donors.

DISCUSSION

The recently adopted national policy to prevent TRALI, i.e. using only plasma donated by males, would have had a positive impact in our setting.

Current status of additive solutions for platelets

The storage of platelets in additive solution (PAS) had lagged behind red cell concentrates, especially in North America. The partial or complete removal of anticoagulated plasma and storage of platelet concentrates in AS presents many advantages. The PAS can be formulated to optimize aerobic metabolism or decrease platelet activation, thus abrogating the platelet storage lesion and potentially improving in vivo viability. Plasma removal has been shown to reduce allergic reactions and the plasma harvested could contribute to the available plasma pool for transfusion or fractionation. PAS coupled to pathogen reduction technology results in a platelet product of equivalent hemostatic efficacy to conventionally stored platelets. Given the above, the likely future direction of platelet storage will be in new generation designer PAS with an extended shelf life and a superior safety profile to plasma stored platelets. J. Clin. Apheresis, 2012. © 2012 Wiley Periodicals, Inc.

TRALI-new challenges for histocompatibility and immunogenetics in transfusion medicine

Antibodies against human leukocyte antigens (HLAs) have long been associated with transfusion-related acute lung injury (TRALI). In contrast to febrile transfusion reactions and refractoriness to platelet transfusions in immunized patients, the causative antibodies in TRALI are present in the transfused blood component, i.e. they are formed by the blood donor and not by the recipient. Consequently, blood components with high plasma volume are particularly associated with TRALI. In addition to antibodies against HLAs, antibodies directed against human neutrophil antigens (HNAs) present in the plasma of predominantly multiparous female blood donors can induce severe TRALI reactions. Especially, antibodies to HLA class II and HNA-3a antigens can induce severe or even fatal ALI in critically ill patients. Over the last decade, the clinical importance of TRALI as major cause for severe transfusion-related morbidities has led to the establishment of new guidelines aimed at preventing this condition, including routine testing for HLA and -HNA antibodies for plasma donors with a history of allogeneic sensitization. This, in turn, poses new challenges for close collaboration between blood transfusion centers and histocompatibility and immunogenetics laboratories, for sensitive and specific detection of the relevant antibodies.

Manufacture of pooled platelets in additive solution and storage in an ELX container after an overnight warm temperature hold of platelet-rich plasma

The processing of whole blood-derived platelet-rich plasma (PRP) to a platelet concentrate and platelet-poor plasma is currently performed within 8 hours to comply with the requirements to manufacture fresh frozen plasma. Maintaining PRP at room temperature for a longer period can have the advantage of shifting the completion of component manufacture onto day shifts. Pairs of ABO-identical prepooled platelets were manufactured by the PRP method, using the current approach with platelet storage in a CLX HP container (Pall Medical, Covina, CA) and plasma, or a novel approach with an 18- to a 24-hour room temperature hold of the PRP and the manufacture of pooled platelets in a glucose-containing additive solution (AS) and storage in a new ELX container (Pall Medical). Standard in vitro assays were performed on days 2, 5, and 7. The results showed that the AS platelets in ELX have in vitro characteristics that are equivalent or superior to those of the standard product.

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.

The incidence, risk factors, and outcome of transfusion-related acute lung injury in a cohort of cardiac surgery patients: a prospective nested case-control study

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Both antibodies and bioactive lipids that have accumulated during storage of blood have been implicated in TRALI pathogenesis. In a single-center, nested, case-control study, patients were prospectively observed for onset of TRALI according to the consensus definition. Of 668 patients, 16 patients (2.4%) developed TRALI. Patient-related risk factors for onset of TRALI were age and time on the cardiopulmonary bypass. Transfusion-related risk factors were total amount of blood products (odds ratio [OR] = 1.2; 95% confidence interval [CI], 1.03-1.44), number of red blood cells stored more than 14 days (OR = 1.6; 95% CI, 1.04-2.37), total amount of plasma (OR = 1.2; 95% CI, 1.03-1.44), presence of antibodies in donor plasma (OR = 8.8; 95% CI, 1.8-44), and total amount of transfused bioactive lipids (OR = 1.0; 95% CI, 1.00-1.07). When adjusted for patient risk factors, only the presence of antibodies in the associated blood products remained a risk factor for TRALI (OR = 14.2; 95% CI, 1.5-132). In-hospital mortality of TRALI was 13% compared with 0% and 3% in transfused and nontransfused patients, respectively (P < .05). In conclusion, the incidence of TRALI is high in cardiac surgery patients and associated with adverse outcome. Our results suggest that cardiac surgery patients may benefit from exclusion of blood products containing HLA/HNA antibodies.

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

BACKGROUND

Although quantitative evidence is lacking, it is generally believed that the majority of cases of transfusion-related acute lung injury (TRALI) are caused by female blood donors. We aimed to examine the relation between female donors and the occurrence of TRALI.

STUDY DESIGN AND METHODS

We performed an international, multicenter case-referent study. TRALI patients who were diagnosed clinically, independent of serology or donor sex, and had received transfusions either only from male donors or only from female donors (unisex cases) were selected. The observed sex distribution among the donors of these TRALI patients was compared to the expected sex distribution, based on the relevant donor populations.

RESULTS

Eighty-three clinical TRALI cases were included; 67 cases received only red blood cells (RBCs), 13 only plasma-rich products, and three both. Among RBC recipients the relative risk (RR) of TRALI after a transfusion from a female donor was 1.2 (95% confidence interval [CI], 0.69-2.1) and among plasma-rich product recipients the RR was 19 (95% CI, 1.9-191). The p value for the difference between RBCs and plasma was 0.023.

CONCLUSION

Our data support the notion that plasma from female donors is associated with an increased risk of TRALI, while RBCs from female donors are not.

Transfusion-related acute lung injury after transfusion of maternal blood: a case-control study

STUDY DESIGN

This is a single-center retrospective case-control study of 7 transfusion-related acute lung injury (TRALI) cases and 28 controls in the pediatric spinal surgery population.

OBJECTIVE

To determine the association between maternal transfusion and risk of TRALI in pediatric spinal surgery patients.

SUMMARY OF BACKGROUND DATA

Previous studies support a "2-hit" model for the pathogenesis of TRALI-activation and sequestration of neutrophils in the pulmonary vasculature followed by transfusion of a biologic response modifier such as antileukocyte antibodies. Maternal donation of blood products is a potential risk factor for TRALI because of the development of antileukocyte antibodies during pregnancy. Until now there have been no studies specifically addressing the risk of TRALI following maternal transfusions.

METHODS

This is a retrospective case-control study of 7 TRALI cases with 4 controls per case, matched by strata for volume of plasma transfused. All cases identified by the Transfusion Biology and Medicine Specialized Center of Clinically Oriented Research with a TRALI diagnosis were eligible for inclusion. Electronic medical records and operative notes were reviewed to obtain demographic data, diagnosis, surgical approach, and number of spine levels for each operation.

RESULTS

An increased prevalence of maternal blood transfusion was found among the TRALI cases compared with the control cases: 43% (3 of 7) versus 7% (2 of 28), P = 0.044. There were otherwise no statistical differences between the groups, including age, gender, surgical approach, number of spinal levels, or type of blood product transfused.

CONCLUSION

Pediatric patients undergoing spinal surgery may be at increased risk for the development of TRALI following the transfusion of maternal blood products. Accordingly, we recommend that directed donation of maternal blood products should be avoided in this population. This study also found that TRALI may be underrecognized and underreported to the transfusion service.