Transfusion-related acute lung injury

The systemic inflammatory response syndrome induces functional changes and relative hyporesponsiveness in neutrophils

PURPOSE

To study the effects of systemic inflammatory response syndrome (SIRS) on polymorhonuclear neutrophil (PMN) function and phenotype by comparing neutrophils from critically ill patients with SIRS against those from healthy blood donors.

MATERIAL AND METHODS

Intensive care unit patients (n = 110) who met at least one SIRS criterion were recruited to the study. One hundred healthy blood donors were recruited as normal controls.

RESULTS

Polymorphonuclear cells from critically ill patients with SIRS were more resistant to activation than PMNs from healthy donors, but when stimulated had an exaggerated microbicidal response. Buffer-treated PMNs from patients with SIRS had significantly higher CD43 surface expression that may inhibit heterotypic cellular contact or ligand stimulation of membrane receptors, had significantly lower expression of IgG receptor CD16, demonstrated resistance to shedding of L-selectin when primed by platelet-activating factor which could be pro-inflammatory, and had reduced respiratory burst when primed by platelet-activating factor than activated by formyl-Met-Leu-Phe.

CONCLUSION

The phenotypic and functional changes observed in neutrophils in the critically ill indicate that they require a higher level of stimulus to become activated. This may represent an auto-protective mechanism where the neutrophils in the already inflamed host may, by this mechanism, avoid excessive inflammation reducing the risk of further host cell injury and death.

Risks associated with fresh whole blood and red blood cell transfusions in a combat support hospital

OBJECTIVE

Fresh whole blood (FWB) and red blood cells (RBCs) are transfused to injured casualties in combat support hospitals. We evaluated the risks of FWB and RBCs transfused to combat-related casualties.

DESIGN

Retrospective chart review.

SETTING

Deployed U.S. Army combat support hospitals.

SUBJECTS

Donors of FWB and recipients of FWB and RBCs.

MEASUREMENTS AND RESULTS

The storage age of RBCs at transfusion was measured as an indicator of overall risk associated with the storage lesion of RBCs between January 2004 and December 2004 at one combat support hospital. Between April 2004 and December 2004, FWB was prescreened only at one combat support hospital for human immunodeficiency virus, hepatitis C virus, and hepatitis B surface antigen before transfusion. To estimate the general incidence of infectious agent contamination in FWB units, samples collected between May 2003 and February 2006 were tested retrospectively for human immunodeficiency virus, hepatitis B surface antigen, hepatitis C virus, and human lymphotropic virus. Results were compared between FWB samples prescreened and not prescreened for infectious agents before transfusion. At one combat support hospital in 2004, 87 patients were transfused 545 units of FWB and 685 patients were transfused 5,294 units of RBCs with a mean age at transfusion of 33 days (+/- 6 days). Retrospective testing of 2,831 samples from FWB donor units transfused in Iraq and Afghanistan between May 2003 and February 2006 indicated that three of 2,831 (0.11%) were positive for hepatitis C virus recombinant immunoblot assay, two of 2,831 (0.07%) were positive for human lymphotropic virus enzyme immunoassay, and none of 2,831 were positive for both human immunodeficiency virus 1/2 and hepatitis B surface antigen by Western blot and neutralization methods, respectively. The differences in the incidence of hepatitis C virus contamination of FWB donor units between those prescreened for hepatitis C virus (zero of 406; 0%) and not prescreened (three of 2,425; 0.12%) were not significant (p = .48).

CONCLUSIONS

The risk of infectious disease transmission with FWB transfusion can be minimized by rapid screening tests before transfusion. Because of the potential adverse outcomes of transfusing RBCs of increased storage age to combat-related trauma patients, the risks and benefits of FWB transfusions must be balanced with those of transfusing old RBCs in patients with life-threatening traumatic injuries.

Blood management: a primer for clinicians

Blood transfusions are common in the hospital setting. Despite the large commitment of resources to the delivery of blood components, many clinicians have only a vague understanding of the complexities associated with blood management and transfusion therapy. The purpose of this primer is to broaden the awareness of health care practitioners in terms of the risks versus benefits of blood transfusions, their economics, and alternative treatments. By developing and implementing comprehensive blood management programs, hospitals can promote safe and clinically effective blood utilization practices. The cornerstones of blood management programs are the implementation of evidence-based transfusion guidelines to reduce variability in transfusion practice, and the employment of multidisciplinary teams to study, implement, and monitor local blood management strategies. Pharmacists can play a key role in blood management programs by providing technical expertise as well as oversight and monitoring of pharmaceutical agents used to reduce the need for allogeneic blood.

The pathogenesis of transfusion-related acute lung injury and how to avoid this serious adverse reaction of transfusion

Transfusion-related acute lung injury (TRALI) is a serious, life-threatening complication of blood transfusion. Available evidence strongly suggests that leukocyte antibodies present in donor plasma are the predominant mechanism in TRALI. These antibodies lead to recipient neutrophil activation, with activated neutrophils inducing endothelial and alveolar damage in the lungs. These mechanisms are discussed in detail as are the alternative mechanisms that have been proposed. Preventive strategies that may help to reduce TRALI are presented.

Transfusion-related acute lung injury in the critically ill: prospective nested case-control study

RATIONALE

Acute lung injury (ALI) that develops 6 hours after transfusion (TRALI) is the leading cause of transfusion-related mortality. Several transfusion characteristics have been postulated as risk factors for TRALI, but the evidence is limited to retrospective studies.

OBJECTIVES

To compare patient and transfusion risk factors between patients who do and do not develop ALI.

METHODS

In this prospective cohort study, consecutive transfused critically ill patients were closely observed for development of ALI. Donor samples were collected from the transfusion bags. Risk factors were compared between patients who developed ALI after transfusion and transfused control patients, matched by age, sex, and admission diagnosis.

MEASUREMENTS AND MAIN RESULTS

Seventy-four of 901 transfused patients developed ALI within 6 hours of transfusion (8%). Compared with transfused control subjects, patients with ALI were more likely to have sepsis (37 vs. 22%, P = 0.016) and a history of chronic alcohol abuse (37 vs. 18%, P = 0.006). When adjusted for patient characteristics, transfusion of plasma from female donors (odds ratio [OR], 5.09; 95% confidence interval [95% CI], 1.37-18.85) rather than male donors (OR, 1.60; 95% CI, 0.76 to 3.37), number of pregnancies among the donors (OR, 1.19; 95% CI, 1.05 to 1.34), number of donor units positive for anti-granulocyte antibodies (OR, 4.85; 95% CI, 1.32-17.86) and anti-HLA class II antibodies (OR, 3.08; 95% CI, 1.15-8.25), and concentration of lysophosphatidylcholine in the donor product (OR, 1.69; 95% CI, 1.10 to 2.59) were associated with the development of ALI.

CONCLUSIONS

Both patient and transfusion risk factors determine the probability of ALI after transfusion. Transfusion factors represent attractive targets for the prevention of ALI.

Transfusion-related immunomodulation (TRIM): an update

Allogeneic blood transfusion (ABT)-related immunomodulation (TRIM) encompasses the laboratory immune aberrations that occur after ABT and their established or purported clinical effects. TRIM is a real biologic phenomenon resulting in at least one established beneficial clinical effect in humans, but the existence of deleterious clinical TRIM effects has not yet been confirmed. Initially, TRIM encompassed effects attributable to ABT by immunomodulatory mechanisms (e.g., cancer recurrence, postoperative infection, or virus activation). More recently, TRIM has also included effects attributable to ABT by pro-inflammatory mechanisms (e.g., multiple-organ failure or mortality). TRIM effects may be mediated by: (1) allogeneic mononuclear cells; (2) white-blood-cell (WBC)-derived soluble mediators; and/or (3) soluble HLA peptides circulating in allogeneic plasma. This review categorizes the available randomized controlled trials based on the inference(s) that they permit about possible mediator(s) of TRIM, and examines the strength of the evidence available for relying on WBC reduction or autologous transfusion to prevent TRIM effects.

Transfusion-related acute lung injury surveillance (2003-2005) and the potential impact of the selective use of plasma from male donors in the American Red Cross

BACKGROUND

American Red Cross surveillance data on transfusion-related acute lung injury (TRALI) fatalities were analyzed to evaluate the association with components from donors with white blood cell (WBC) antibodies and to examine the potential impact of the selective transfusion of plasma from male donors.

STUDY DESIGN AND METHODS

Suspected TRALI reports in 2003 through 2005 were identified and all fatalities were reviewed and classified by three physicians as "probable TRALI" or of "unrelated etiology," with independent review of the associated serologic investigation. Hospital investigational and reporting biases could not be fully controlled in this retrospective study.

RESULTS

A total of 550 reports of suspected TRALI, including 72 fatalities, were investigated. The number of reports increased each year and the rate varied by geographic region. Retrospective review of fatalities revealed 38 cases of probable TRALI, the majority (24 of 38 [63%]) after plasma transfusion. A female, WBC antibody-positive donor was involved in 71 percent (27 of 38) of cases and in 75 percent (18 of 24) of cases involving plasma transfusion. Female antibody-positive donors were more likely to be associated with probable TRALI than with unrelated cases (p = 0.0001; odds ratio [OR], 9.5; 95% confidence interval [CI], 2.9-31.1]. The rate of probable TRALI among recipient fatalities was higher for plasma components (1:202,673; OR, 12.5; 95% CI, 5.4-28.9) and apheresis platelets (PLTs; 1:320,572; OR, 7.9; 95% CI, 2.5-24.8) compared to red cells (1:2,527,437). Male donors contributed 64.5 and 52.0 percent of distributed apheresis PLTs and plasma components, respectively, in 2005.

CONCLUSION

Plasma components linked to female donors with WBC antibodies were responsible for the majority of probable TRALI fatalities. Prudent measures to limit transfusion of WBC antibody-containing plasma components may prevent as many as six fatalities per year in the Red Cross system.

A pediatric case of transfusion-related acute lung injury following bone marrow infusion

TRALI is a rare but serious complication associated with transfusion, and known to occur following infusion of all types of plasma-containing blood products. However, only one adult case of TRALI after allogenic marrow graft has been reported. In this study, we present a pediatric case possibly associated with allogenic marrow infusion. A 10-yr-old girl was referred to our hospital for the treatment of acute myeloid leukemia. She underwent allogenic bone marrow transplantation from her HLA-2-loci-mismatched mother. During conditioning, she suffered from bacterial sepsis, but it had improved with antibiotics until day 0 of transplantation. Two h after starting the marrow infusion, she developed severe hypoxia. We discontinued the infusion and started steroids, which improved her respiratory condition. However, she developed respiratory failure again after resuming infusion of the graft. Despite intensive care with mechanical ventilation, the patient died of endotoxin shock five days after transplantation. Although we could not identify the antibody which might have been involved in the respiratory distress, the clear temporal relationship between marrow infusion and respiratory distress suggested that similar acute lung injury to TRALI might have occurred following allogenic marrow infusion in the present case.

Stored packed red blood cell transfusion up-regulates inflammatory gene expression in circulating leukocytes

SUMMARY BACKGROUND DATA

The transfusion of more than 6 units of packed red blood cells (PRBCs) within the first 12 hours of injury is the strongest independent predictor of multiple organ failure (MOF). This suggests that stored blood contains bioactive factors that may modify the immunoinflammatory response.

METHODS

To simulate postinjury major transfusions ex vivo, we obtained whole blood from 4 healthy adults and divided it into four 7-mL groups (I-IV). Group I was not diluted. Group II had 7 mL of 0.9% sterile saline (SS) added. Group III received 3.5 mL each of leuko-reduced stored PRBC and SS (simulating a major transfusion). Group IV received 3.5 mL each of SS and a hemoglobin-based oxygen carrier (PolyHeme) to evaluate the effects of hemoglobin alone. The hemoglobin content in groups III and IV was measured to be equal. Total leukocyte RNA was purified, and its gene array profiles were obtained.

RESULTS

Of the 56,475 oligonucleotide probe sets interrogated, 415 were statistically different (P < 0.001). Fourteen of the 415 probe sets were inflammatory-related. The PRBC group had a significantly different expression profile compared with the others and included up-regulation of the interleukin-8, toll-like receptor 4, cryropyrin, prostaglandin-endoperoxide synthase-2, and heparinase genes.

CONCLUSIONS

PRBCs activate inflammatory genes in circulating leukocytes, which may be central to the pathogenesis of the adverse inflammatory responses that lead to postinjury MOF.

Increased permeability-oedema and atelectasis in pulmonary dysfunction after trauma and surgery: a prospective cohort study

BACKGROUND

Trauma and surgery may be complicated by pulmonary dysfunction, acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), but the mechanisms are incompletely understood.

METHODS

We evaluated lung capillary protein permeability non-invasively with help of the 67Ga-transferrin pulmonary leak index (PLI) technique and extravascular lung water (EVLW) by the transpulmonary thermal-dye dilution technique in consecutive, mechanically ventilated patients in the intensive care unit within 24 h of direct, blunt thoracic trauma (n = 5, 2 with ARDS), and within 12 h of indirect trauma by transhiatal oesophagectomy (n = 8), abdominal surgery for cancer (n = 6) and bone surgery (n = 4). We studied transfusion history, haemodynamics, oxygenation and mechanics of the lungs. The lung injury score (LIS, 0-4) was calculated. Plain radiography was also done to judge densities and atelectasis.

RESULTS

The PLI and EVLW were elevated above normal in 61 and 30% of patients, respectively, and the PLI directly related to the number of red cell concentrates given (rs = 0.69, P < 0.001), without group differences. Oxygenation, lung mechanics, radiographic densities and thus the LIS (1.0 [0.25-3.5]) did not relate to PLI and EVLW. However, groups differed in oxygenation and airway pressures and impaired oxygenation related to the number of radiographic quadrants with densities (rs = 0.55, P = 0.007). Thoracic trauma patients had a worse oxygenation requiring higher airway pressures and thus higher LIS than the other patient groups, unrelated to PLI and EVLW but attributable to a higher cardiac output and thereby venous admixture. Finally, patients with radiographic signs of atelectasis had more impaired oxygenation and more densities than those without.

CONCLUSION

The oxygenation defect and radiographic densities in mechanically ventilated patients with pulmonary dysfunction and ALI/ARDS after trauma and surgery are likely caused by atelectasis rather than by increased permeability-oedema related to red cell transfusion.

Transfusion from male-only versus female donors in critically ill recipients of high plasma volume components

OBJECTIVE

To reduce the incidence of transfusion-related acute lung injury (ALI), the American Association of Blood Banks recently recommended rapid implementation of strategies to minimize transfusion of high plasma volume components, fresh frozen plasma and apheresis platelets, from potentially alloimmunized donors, especially females. The objective of this study was to evaluate the effect of transfusing components from male-only vs. female donors on development of ALI, gas exchange, and outcome in critically ill patients.

DESIGN

In this retrospective case-control study, we identified patients who received high plasma volume components from male-only donors and compared them with patients matched by severity of illness, postoperative state, and number of transfusions but who received high plasma volume components from female donors.

SETTING

Four intensive care units at a tertiary medical center.

PATIENTS

Critically ill patients who received >2 units of fresh frozen plasma or apheresis platelets.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

From a database of 3,567 patients who received a total of 46,101 units of fresh frozen plasma and 6,251 units of apheresis platelets, we identified 112 patients who received three or more male-only donor components and 112 matched controls. Baseline characteristics, ALI risk factors, and development of ALI were similar between the two groups. Arterial oxygenation (PaO2/FIO2) worsened after the female (mean difference -52, 95% confidence interval -14 to -91, p = .008) but not after male-only donor product transfusion (mean difference 22, 95% confidence interval -23 to 67, p = .325). Male-only component recipients had more ventilator-free days (median 28 vs. 27, p = .006) and a trend toward lower hospital mortality rates (14% vs. 24%, p = .054).

CONCLUSIONS

In critically ill recipients of high plasma volume components, gas exchange worsened significantly after transfusion of female but not male donor components. Prospective studies are needed to evaluate the effect of recommendations by the American Association of Blood Banks on outcome of transfused critically ill patients.

The pathogenesis of transfusion-related acute lung injury (TRALI)

In recent years, transfusion-related acute lung injury (TRALI) has developed from an almost unknown transfusion reaction to the most common cause of transfusion-related major morbidities and fatalities. A clinical definition of TRALI was established in 2004, based on acute respiratory distress, non-cardiogenic lung oedema temporal association with transfusion and hypoxaemia. Histological findings reveal lung oedema, capillary leucostasis and neutrophil extravasation. However, the pathogenesis of TRALI remains controversial. Leucocyte antibodies, present in fresh frozen plasma and platelet concentrates from multiparous donors, and neutrophil priming agents released in stored cellular blood components have been considered to be causative. As neutrophils and endothelial cells are pivotal in the pathogenesis of TRALI, a threshold model was established to try to unify the various reported findings on pathogenesis. This model comprises the priming of neutrophils and/or endothelium by the patient's co-morbidity, neutrophil and/or endothelial cell activation by the transfused blood component, and the severity of the TRALI reaction.

[Transfusion-related acute lung injury]

OBJECTIVES

The transfusion-related acute lung injury frequency was for a long time underestimated since it lacked both a widely accepted clinical definition and a comprehensive etiologic description. Recent clinical and biological data have underlined its frequency and have allowed a better understanding of its mechanisms.

CURRENT KNOWLEDGE AND KEY POINTS

Trali is an interstitial lung injury occurring within 6 hours after the beginning of a blood transfusion. This time relationship between blood injection and the occurrence of lung edema is sufficient for a positive diagnosis, if any other cause of interstitial lung edema have been excluded. The clinical definition relies on a desaturation of arterial blood associated to a lack of any cardiac failure or circulation overload. The link between transfusion and lung edema is not univocal and several categories of mechanisms have been discussed. At least 2 of them are well identified; the first one is an immune conflict, and the second one is an activation of neutrophils by injection of biological modifiers such as lipids or CD40 soluble ligand. Evidences exist for the occurrence of Trali only in predisposing condition that mostly consists of a preceding leucostase in lung capillaries. Trali is treated like other lung interstitial edema by oxygen therapy and mechanical ventilation.

FUTURE PROJECTS

A better knowledge of Trali offers the opportunity of improving the understanding of the role of blood transfusion in lung edema occurring in complex situations and open the way for a better definition of at risk patient and at risk blood components.

Histoblood groups other than HLA in organ transplantation

Immunological matching of a living related donor and recipient of an allograft is precise, but for cadaver organs matching is controversial, including at least detection of specific sensitization in the recipient against the donor, especially for HLA-DR. With the publication of some cases of ABO histoblood group incompatible transplantations with favorable outcomes, transplantation immunologists now focus on many of the 29 International Society of Blood Transfusion-approved histoblood group systems. So far, research lags behind knowledge about which system occurs in which organ, but modern molecular biology tests, like basic local alignment search tools (BLAST) and the recent inclusion of some systems into the CD classification, make possible the tracking of some histoblood group epitopes to specific tissue components. We have conducted such a search. With respect to tissue distribution, mRNA transcripts, and expressed sequence tags (EST), we observed a huge variety of distribution patterns. The total number of EST in the embryo pool was 752,991 and in the adult pool 1,227,835. Representative results were described for umbilical cord, bone marrow, peripheral stem cells, the nervous system, and the embryo. The ABO histoblood group systems maintain high priority for matching, because of the occurrence of naturally occurring anti-A/B antibodies. Substantial progress has been made in monitoring their levels and immunoglobulin isotypes in recipients, which, beyond hemagglutination, can now be quantitated using ELISA or cytofluorometry. A picture of ever-improving compatibility matching in solid organ and stem cell transplantation beyond mere HLA typing is the consequence.

Lesão pulmonar aguda associada à transfusão

Lesão pulmonar aguda associada à transfusão (transfusion-related acute lung injury, TRALI) é uma complicação clínica grave relacionada à transfusão de hemocomponentes que contêm plasma. Recentemente, TRALI foi considerada a principal causa de morte associada à transfusão nos Estados Unidos e Reino Unido. É manifestada tipicamente por dispnéia, hipoxemia, hipotensão, febre e edema pulmonar não cardiogênico, que ocorre durante ou dentro de 6 h, após completada a transfusão. Embora o exato mecanismo não tenha sido totalmente elucidado, postula-se que TRALI esteja associada à infusão de anticorpos contra antígenos leucocitários (classes I ou II ou aloantígenos específicos de neutrófilos) e a mediadores biologicamente ativos presentes em componentes celulares estocados. A maioria dos doadores implicados em casos da TRALI são mulheres multíparas. TRALI, além de ser pouco diagnosticada, pode ainda ser confundida com outras situações de insuficiência respiratória aguda. Um melhor conhecimento sobre TRALI pode ser crucial na prevenção e tratamento desta severa complicação transfusional.

Transfusion-related acute lung injury in patients with burns

Transfusion-related acute lung injury (TRALI) has not been systematically described in patients with burn injury, and the characterization of TRALI in patients with pre-existing acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) also is lacking. Our aim was to identify TRALI in burn patients and to attempt to characterize transfusion (TXN)-related pulmonary deterioration in burn patients with pre-existing ALI or ARDS. We undertook a retrospective review of mechanically ventilated and transfused burn patients at an adult regional burn center between January 1, 2003, and January 5, 2005. A blinded intensivist independently rated pre- and post-TXN chest radiographs (CXRs). There were 25 patients (age 51 +/- 19 years, %TBSA burns 30 +/- 19, full thickness %BSA 17 +/- 19, with a 24% incidence of smoke inhalation) who received 124 TXNs. New ALI developed within 6 hours after four TXNs. In one TXN, there were no other precipitating causes (eg, infection, inhalation injury), suggesting possible TRALI (incidence 0.8%). Existing ALI or ARDS was present before 63 (51%) of the TXNs. Definite worsening of the CXR and deterioration in the PaO2/FiO2 ratio (18% +/- 4%) within 6 hours of TXN occurred after six transfusions. In two of the TXNs, there were no other precipitating causes, suggesting possible TXN-related pulmonary deterioration (incidence 3.2%). Vigilance must be maintained for TRALI in burn patients. For patients with existing ALI or ARDS, we suggest that worsening of the CXR and reduction in the PaO2/FiO2 ratio by 20% or more within 6 hours of transfusion should be investigated for possible TRALI with appropriate donor investigations.

Early noncardiogenic pulmonary edema and the use of PEEP and prone ventilation after emergency liver transplantation

Noncardiogenic pulmonary edema in liver transplant recipients is usually secondary to TRALI (transfusion related acute lung injury) or liver ischemic-reperfusion injury. If persistent, the resultant hypoxemia is associated with increased ventilator days, prolonged length of stay (intensive care and hospital) and increased 28-day mortality. Ventilation strategies for the management of hypoxemia in acute lung injury include moderate to high levels of PEEP (positive and expiratory pressure) and prone ventilation (PV). Such strategies have theoretical adverse effects on graft perfusion. Evidence does however exist to demonstrate that maintenance of cardiac output and correct positioning of the prone patient to allow abdominal excursion can negate the deleterious effects of PEEP and PV. A liver transplant recipient became profoundly hypoxemic on our intensive care unit following the onset of noncardiogenic pulmonary edema. A risk-benefit assessment performed at the time deemed that the potential adverse effects of PEEP and PV were outweighed by the life-threatening nature of hypoxemia. The patient's condition improved following prone positioning and application of PEEP (10-15 cm H(2)O). We conclude that such ventilation strategies are appropriate in hypoxemic liver transplant recipients if an appropriate risk-benefit assessment is performed.

Generation of inflammatory cytokines and chemokines from peripheral blood mononuclear cells by HLA Class II antibody-containing plasma unit that was associated with severe nonhemolytic transfusion reactions

BACKGROUND

HLA Class II antibodies are thought to be involved in severe transfusion reactions including transfusion-related acute lung injury (TRALI). The activation of monocytes by HLA Class II antibody may play an important role in the etiology of TRALI.

CASE REPORT

An 81-year-old man with non-Hodgkin's lymphoma (Clinical Stage IIIA) received a plateletpheresis unit containing at least 4 x 10(11) platelets because of thrombocytopenia and a bleeding tendency. Approximately 30 minutes after the start of transfusion, he developed chills, tachycardia, dyspnea, lumber, and abdominal pain and then a fever (40.3 degrees C). His SaO(2) dropped to 70 percent. The transfusion was discontinued immediately. His symptoms disappeared after treatment with oxygen and the administration of corticosteroid and aminophyrine. A chest X-ray showed no sign of pulmonary edema.

RESULTS

The donor serum sample had HLA-DR antibodies against multiple DR antigens including DR13, the recipient's HLA-DR type. The cross-match between the patient's lymphocytes and the donor serum was positive. The treatment of peripheral blood mononuclear cells from healthy subjects bearing DR13 antigen with the donor plasma caused the secretion of inflammatory cytokines (i.e., interleukin [IL]-1beta, IL-6, and tumor necrosis factor-alpha) and neutrophil-activating chemokines (i.e., IL-8 and CXCL1/GRO-alpha) in a cognate antigen-antibody relationship. In addition, the secretion of inflammatory cytokines appeared to require the involvement of CD32 and/or CD16.

CONCLUSION

HLA-DR antibodies, detected in this case, had biologic functions to induce production of not only inflammatory cytokines but also neutrophil-attractant chemokines in vitro, which could contribute to the etiology of severe nonhemolytic transfusion reactions.

Intravenous Busulfan and Melphalan, Tacrolimus, and Short-Course Methotrexate Followed by Unmodified HLA-Matched Related or Unrelated Hematopoietic Stem Cell Transplantation for the Treatment of Advanced Hematologic Malignancies

Results of allogeneic hematopoietic stem cell transplantation (HCT) to treat advanced leukemia or myelodysplastic syndrome (MDS) remain poor due to excessive relapse and transplant-related mortality. To improve transplant outcome in this patient population, 43 patients (median age, 46.1 years) with high-risk or advanced lymphoid (n = 5) or myeloid malignancy (n = 38) were prospectively enrolled on a pilot trial of cytoreduction with intravenous busulfan and melphalan followed by an unmodified HLA-A, -B, and -DRbeta1-matched related (n = 18) or unrelated (n = 25) HCT. Graft-versus-host disease (GVHD) prophylaxis consisted of tacrolimus and methotrexate. Thirty-four patients had > or = 5% blasts at the time of HCT; 12 of these had > 20% blasts. Seventeen patients had unfavorable cytogenetics, 8 patients underwent transplantation for secondary MDS or acute myelogenous leukemia, and 4 patients had relapsed after a previous allogeneic transplantation. Although mucositis was the most significant regimen-related toxicity, requiring the addition of folinic acid rescue and failure to receive all 4 doses of methotrexate in 23 patients, the nonrelapse mortality at 30 and 100 days was low at 0% and 16%, respectively. The cumulative incidence of grade II-IV acute GVHD was 24%, and that of extensive chronic GVHD was 7%. With a minimum follow-up of 18 months, the estimated 3-year overall survival is 37% and the estimated disease-free survival (DFS) is 33%. For 18 patients with MDS (< or = RAEB-2) or high-risk myeloproliferative disorder, the estimated 3 year DFS is 61%. These data demonstrate the curative potential of this regimen in patients with high-risk myeloid malignancies.

Peritoneal hemorrhage due to a ruptured ovarian cyst in ITP

Immune thrombocytopenic purpura in children rarely causes severe bleeding. The incidence of intracranial hemorrhage is approximately 0.2% to 1.0%, and severe bleeding (defined as persistent epistaxis, melena, menorrhagia, gastrointestinal bleeding, etc, requiring hospitalization or transfusion) occurs in only 5% of patients. Epstein-Barr virus (EBV) associated idiopathic thrombocytopenic purpura (ITP) tends to behave similarly to non-EBV - associated ITP with no increase in hemorrhagic complications and only a small increase in time to remission. Immune thrombocytopenic purpura diagnosed in adolescence is more likely to be chronic then in childhood ITP, but has a higher rate of spontaneous resolution than in adults. However, females in this age group are in their early childbearing years and present a unique set of possible hemorrhagic complications not seen in younger patients. We present the case of an 18-year-old female with EBV-associated ITP, who developed a severe intra-abdominal bleed secondary to a hemorrhagic ovarian cyst.

Anti-inflammatory Strategies and Hemostatic Agents: Old Drugs, New Ideas

Hemostatic abnormalities occur following injury associated with both cardiac and noncardiac surgery. These changes are part of inflammatory pathways with signaling mechanisms that link these diverse pathways. The inflammatory response to surgery is exacerbated by allogeneic blood transfusion by enhancing intrinsic inflammatory activity and directly increasing plasma levels of inflammatory mediators. Surgical patients can be preventively treated with pharmacologic agents to modulate inflammatory responses. Multiple studies have reported preventive pharmacologic therapies to reduce bleeding and the need for allogeneic transfusions in surgery. Strategies for cardiac surgical patients during cardiopulmonary bypass include administration of either lysine analogs, such as epsilon aminocaproic acid and tranexamic acid, or the serine protease inhibitor aprotinin.

Transfusion-related Acute Lung Injury

With the success of reducing the risk of transfusion-transmitted infectious diseases, noninfectious serious hazards of transfusion have come to the forefront with respect to transfusion safety. Transfusion-related acute lung injury has emerged as a dominant noninfectious serious hazard of transfusion. Improved understanding of its pathophysiology is needed to improve clinical strategies to deal with the risk. Such understanding, in turn, will depend on the continued progress in development of good model systems, in vitro and in vivo, for experimental studies. As the pathologic mechanisms are elucidated, a universal definition and strategies for the prevention and/or mitigation may become more tangible. This article reviews the clinical manifestations, evolving definition, incidence, pathophysiology, animal modeling, and donor screening and deferral algorithms as they relate to transfusion-related acute lung injury.

An association of soluble CD40 ligand (CD154) with adverse reactions to platelet transfusions

BACKGROUND

Removal of stored supernatant abrogates most transfusion reactions to leukoreduced platelets (PLTs), suggesting that PLT-derived soluble mediators are involved. PLTs are the primary source of soluble CD40 ligand (sCD40L). Engagement of the receptor for CD40L induces synthesis of proinflammatory mediators including interleukin (IL)-6, IL-8, and monocyte chemotactic protein-1 (MCP-1).

STUDY DESIGN AND METHODS

Supernatants from poststorage leukoreduced PLT concentrates were assayed for white cell- (IL-6, IL-8, MCP-1) and PLT-derived (sCD40L, RANTES) inflammatory mediators. These levels were correlated with clinical outcomes.

RESULTS

Of 534 transfusions, there were 12 reported (2.2%) and 2 unreported reactions (0.4%)--10 febrile and 4 allergic. Transfusions with reactions had significantly higher levels of IL-6 (2.3-fold higher; p = 0.005), IL-8 (2.2-fold higher; p = 0.001), MCP-1 (2.6-fold higher; p = 0.002), and sCD40L (1.24-fold higher; p = 0.015), but not RANTES. (1.14-fold higher; p = 0.22). The vast majority (>93%) of patients transfused with mediator levels in the highest quintile had no reactions. When levels of all five mediators were summed, the reaction rates in the first through fifth quintiles increased from 1 to 7 percent (p = 0.027). All but one reaction occurred in patients with hematologic malignancies (13 reactions/380 transfusions; 3.4%; p = 0.04 vs. other diagnoses).

CONCLUSIONS

These are the first data demonstrating that a PLT-derived mediator, sCD40L, is associated with adverse transfusion events. Existing clinical factors, for example, inflammation or leukopenia, may influence whether infused mediators cause reactions.

Error management of emergency transfusions: A surveillance system to detect safety risks in day to day practice

Acute hemolysis due to AB0-incompatibility caused by transfusion of red blood cell concentrates (RBCC) to the wrong recipient is one of the major causes of transfusion-related death. As part of our policy to improve quality and safety in emergency transfusion, we have developed a standardized surveillance system for supplying RBCC in emergency situations. This surveillance system involves the implementation of a standardized set of basic data transmitted from the requesting unit to the blood bank by phone and a scoring system to check for compliance with guidelines and errors in daily routines. Communication deficiencies and delayed pretransfusion sampling were the most common errors.

Lung microvascular endothelial cell injury caused by treatment with polymorphonuclear neutrophils and low-IgM serum: a model of transfusion-related acute lung injury

Transfusion-related acute lung injury (TRALI) is one of the serious side effects that occur immediately after blood transfusion. The etiology of TRALI may be attributed to the presence of anti-human leukocyte antigen (HLA) and/or anti-polymorphonuclear neutrophil (PMN) antibodies in the plasma of donor blood products. However, the precise mechanisms underlying the development of TRALI are unclear to date. To further evaluate mechanisms we investigated the relationship between human lung microvascular endothelial cell (LME cell) lysis and normal human serum. We found the LME cell lysis occurred within 4 h of combining LME cells with PMNs and low-IgM serum, but not with high-IgM serum, without serum, or with PMNs alone. By flow cytometry and modified ELISA, the specific binding of not only PMN surface proteins but also intact PMNs to LME cells was observed in the presence of low-IgM serum but not in the presence of high-IgM serum or in the absence of serum. The blocking of CD7 expressed on LME cells or the blocking of CD16 or CD32 on PMNs by pretreatment with monoclonal antibodies (mAbs) inhibited LME cell lysis. Moreover, two serum samples with low lgM obtained from blood donors whose sera contained anti-PMN antibodies caused LME cell lysis in the presence of PMNs. Furthermore, the addition of an elastase inhibitor inhibited the lysis of LME cells caused by the treatment with PMNs and low-IgM serum. Our present results suggest that PMNs and low-IgM serum are the likely components in the development of TRALI.

Transfusion-related acute lung injury and pulmonary edema in critically ill patients: a retrospective study

BACKGROUND

Using the recent Consensus Panel recommendations, we sought to describe the incidence of transfusion-related acute lung injury (TRALI) and transfusion-associated circulatory overload (TACO) in critically ill patients.

STUDY DESIGN AND METHODS

Consecutive patients at four intensive care units (ICUs) who did not require respiratory support at the time of transfusion were identified with custom electronic surveillance system that prospectively tracks the time of transfusion and onset of respiratory support. Respiratory failure was defined as the onset of noninvasive or invasive ventilator support within 6 hours of transfusion. Experts blinded to specific transfusion factors categorized the cases of pulmonary edema as permeability edema (suspected or possible TRALI) or hydrostatic edema (TACO) according to predefined algorithm. In a nested case-control design, transfusion variables and lung injury risk factors were compared between the TRALI cases and controls matched by age, sex, and admission diagnosis.

RESULTS

There were 8902 units transfused in 1351 patients of whom 94 required new respiratory support within 6 hours of transfusion. Among 49 patients with confirmed acute pulmonary edema, experts identified 7 cases with suspected TRALI, 17 patients with possible TRALI, and 25 cases with TACO. The incidence of suspected TRALI was 1 in 1271 units transfused; possible TRALI, 1 in 534 per unit transfused; and TACO, 1 in 356 per unit transfused. When adjusted for sepsis and fluid balance in a stepwise conditional logistic regression analysis, patients who developed acute lung injury (suspected or possible TRALI) received larger amount of plasma (odds ratio 3.4, 95% confidence interval 1.2-10.2, for each liter infused; p = 0.023).

CONCLUSION

In the ICU, pulmonary edema frequently occurs after blood transfusion. The association between infusion of plasma and the development of suspected or possible TRALI may have important implications with regards to etiology and prevention of this syndrome.

An update on solutions for red cell storage

Anticoagulant and nutrient solutions allow red blood cells to be stored and transported, enabling modern blood banking. The development of these solutions has been slow, covering 90 years, and the reasons for past formulations are best understood in a historical context. Modern red cell storage solutions work well for blood banks, allowing 5-7-week storage, which means more than 90% of collected units find a recipient. Improved scientific understanding of the red cell storage lesion has shown a way to make even better storage solutions, which maintain red cell metabolism and reduce membrane loss.

Transfusion-related acute lung injury (TRALI)--an important, severe transfusion-related complication

BACKGROUND

Transfusion-related acute lung injury (TRALI) is an immune-mediated transfusion reaction that can cause severe complications or even death. It is now the leading cause of transfusion-related death in the United States.

METHODS

The TRALI syndrome is presented in two cases in a surgical intensive care unit and discussed against the background of the present literature. In both cases, concomitant diseases led to an extremely difficult course of TRALI.

CONCLUSIONS

Knowledge of the TRALI syndrome is necessary to enable early diagnosis and treatment. It should be taken into consideration at any time when cardiopulmonary instability occurs after transfusion of blood products, which is a frequent event on surgical Intensive Care Units. TRALI remains a clinical diagnosis supported by serologic studies if these are available. Against the background of this potentially life-threatening complication, every single indication to transfuse blood products needs to be scrutinized carefully.

Transfusion-related acute lung injury: a literature review

Transfusion-related acute lung injury (TRALI) is a serious and potentially fatal complication of transfusion of blood and blood components. TRALI is under-diagnosed and under-reported because of a lack of awareness. A number of models have been proposed to explain the pathogenesis of TRALI: an antibody mediated model; a two-event biologically active mediator model; and a combined model. TRALI can occur with any type of blood product and can occur with as little as one unit. Its presentation is similar to other forms of acute lung injury and management is predominantly supportive. The main strategy in combating TRALI is prevention both through manipulation of the donor pool and through clinical strategies directed at reducing transfusion of blood products including, but not limited to, evidence-based lower transfusion thresholds. This article presents a review of TRALI and addresses the definition, pathology, pathogenesis, clinical manifestations, treatment and prevention of the syndrome.

Pulmonary consequences of transfusion: TRALI and TACO

Transfusion-related acute lung injury and transfusion-associated circulatory overload are important, life-threatening complications of transfusion. Each adversely impact hospital length of stay and cost of healthcare. TRALI is clinically indistinguishable from the adult respiratory distress syndrome but it has a more favorable prognosis. Approximately 10% of TRALI patients die from this complication. The at-risk patient for TRALI has not been identified. The most commonly cited incidence is 1:5000 plasma-containing blood component transfusions. Although several pathways may lead to TRALI, passive transfusion of leukocyte antibodies is currently the most important association. TACO occurs in 1-8% of patients undergoing hip or knee arthroplasty. It is precipitated by positive fluid balance and high transfusion flow rates. TACO is characterized by respiratory distress and acute pulmonary edema.

Präoperative Eigenblutspende in der Herzchirurgie

BACKGROUND

Preoperative autologous blood donation is an effective method to reduce allogeneic transfusion requirement. However, this method is only rarely utilized in cardiac surgery. Besides economic concerns one essential argument against predonation is the lack of sufficient time due to the short waiting lists. The aim of the present study was to investigate the efficacy of autologous predonation to reduce allogeneic blood transfusion in routine cardiac surgery on a center without longer preoperative waiting lists.

PATIENTS AND METHODS

A total of 2,626 cardiac surgery patients were included. Primary endpoint of the study was the perioperative incidence of allogeneic packed cell transfusion. If time between diagnosis and admission to the hospital was >10 days, predonation was offered to the patients. Data were stratified for preoperative risk score. Logistic and linear regression analysis tested the influence of different variables on the incidence of allogeneic blood transfusion and the total amount of allogeneic blood.

RESULTS

Of all patients 267 (11.2%) underwent predonation. The incidence of allogeneic packed cell transfusion was reduced from 53% to 19% by autologous predonation (p<0.001). The total amount of allogeneic blood transfused was significantly different between the groups (2.2+/-4.2 vs. 0.84+/-6.3 units; p<0.001).

DISCUSSION

Autologous predonation in cardiac surgery was effective in reducing blood transfusions even in the absence of longer preoperative waiting times. It is a safe and effective method to minimize blood transfusion in cardiac surgery.

Recombinant factor VIIa in patients with coagulopathy secondary to anticoagulant therapy, cirrhosis, or severe traumatic injury: review of safety profile

BACKGROUND

In recent years, the hemostatic agent recombinant factor VIIa (rFVIIa) has emerged as a potentially new therapeutic agent for management of coagulopathy in patients with cirrhosis or following severe traumatic injury, a complex problem for clinicians in which standard treatment strategies are not always effective. As with other hemostatic agents, a primary safety concern of rFVIIa therapy is the theoretical possibility that systemic administration could confer an increased risk of thrombotic complications. So far, clinical experience indicates rFVIIa to be a safe treatment for currently approved indications within hemophilia. Little information is available, however, for patient populations outside this clinical setting.

STUDY DESIGN AND METHODS

This article reviews critical safety data obtained from 13 Novo Nordisk-sponsored clinical trials of rFVIIa in patients with coagulopathy secondary to anticoagulant therapy, cirrhosis, or severe traumatic injury.

RESULTS

Thrombotic adverse events were reported for 5.3 percent (23/430) of placebo-treated patients and 6.0 percent (45/748) of patients on active treatment. No significant difference was found between placebo-treated and rFVIIa-treated patients with respect to the incidence of thrombotic AEs, either on an individual trial basis or for these trial populations combined (p=0.57).

CONCLUSION

An important determinant for the safety profile reported here is likely to be the specific mechanism of action of rFVIIa, shown in experimental studies to be localized to the site of vascular injury where tissue factor is exposed.

TRALI in 2 cases of leukemia

We describe transfusion-related acute lung injury (TRALI) in 2 acute leukemia cases to increase awareness of this under reported serious transfusion complication syndrome in multitransfused patients. There are a number of reports in multitransfused patients with nonmalignant disorders. However, reports of pediatric oncology patients are few, suggesting a lack of recognition or misdiagnosis of the syndrome. A disproportionately high number of fatalities in children is recorded in the literature. This highlights the need for increased awareness and appropriate treatment of this serious complication of transfusion. Although TRALI is initially a clinical diagnosis, the laboratory investigation is vital as it contributes to defining the pathogenesis of the syndrome and importantly facilitates the effective management of implicated donations and donors. An investigational strategy for suspected cases is presented and the results are discussed in the context of current proposed mechanisms for TRALI. As each transfused blood product is associated with a potential risk of TRALI, more frequent reports in patients receiving large volume or recurrent transfusion would be expected.

The two-event model of transfusion-related acute lung injury

The objective of this review is to present the two-event model of transfusion-related acute lung injury (TRALI), a life-threatening complication of transfusions that has been the most common cause of transfusion-related death over the past 2 yrs in the United States. The two-event model of TRALI, which is identical to the pathogenesis of the acute respiratory distress syndrome (ARDS), is reviewed and contrasted to antibody-mediated TRALI. Laboratory studies, both in vitro and in vivo, are discussed as well as human studies of TRALI. Methods to avoid patient exposure to blood components that may cause TRALI are also discussed.

Animal models of transfusion-related acute lung injury

OBJECTIVE

To examine the existing animal models of transfusion-related acute lung injury (TRALI) for insight into disease pathogenesis.

DATA SOURCE

The data were taken from published research and from our own experimental results.

RESULTS

Animal models have disproved the microaggregate theory of acute lung injury from blood transfusions. The two major hypotheses of TRALI, passively transfused neutrophil and human leukocyte antigen antibodies and biologically active lipids that accumulate in older, cellular blood products, have been replicated in animal models. The proposed two-hit model of TRALI is also supported by animal studies. A new in vivo mouse model of TRALI based on major histocompatibility complex (MHC) I antibodies has replicated several features of human TRALI, focusing prominently on the role of neutrophils.

CONCLUSIONS

Experimental animal models support both the antibody and lipid theories of TRALI. The essential role of neutrophils to producing lung injury is common to all existing models of TRALI. There is a lack of clinically relevant animal models that explain why transfusion of donor antibodies to cognate antigens in the recipient does not always lead to TRALI.

Mechanisms of transfusion-related acute lung injury (TRALI): anti-leukocyte antibodies

There is abundant evidence that leukocyte antibodies in blood donor products are somehow involved in transfusion-related acute lung injury (TRALI). Human leukocyte antigen (HLA) class I, HLA class II, and neutrophil-specific antibodies in the plasma of both blood donors and recipients have been implicated in the pathogenesis of TRALI. The case for a relationship between leukocyte antibodies and TRALI is more compelling if concordance between the antigen specificity of the leukocyte antibodies in the donor plasma and the corresponding antigen on the cells of the affected recipient is demonstrated. Such antibody-antigen concordance can be investigated by typing the recipient for the cognate leukocyte antigens or by cross-matching the donor plasma against the recipient's leukocytes. Two proposed pathophysiologic mechanisms for TRALI have received the most attention: the antibody hypothesis and the two-event hypothesis. The final common pathway in all of the proposed pathogenic mechanisms of TRALI is increased pulmonary capillary permeability, which results in movement of plasma into the alveolar space causing pulmonary edema. A typical TRALI serologic workup consists of tests for HLA class I and II and neutrophil-specific antibodies. The use of flow cytometry and HLA-coated microbeads is recommended for detection of HLA antibodies in plasma of implicated blood donors and a combination of the granulocyte agglutination test and granulocyte immunofluorescence test for detection of neutrophil-specific antibodies. Genotyping for class I and II HLA and for a limited number of neutrophil antigens may also be helpful in establishing antibody-antigen concordance.

Transfusion-related acute lung injury (TRALI): clinical presentation, treatment, and prognosis

The term transfusion-related acute lung injury (TRALI) was coined in 1983 to describe a constellation of clinical and laboratory features seen within 6 hrs of the transfusion of plasma-containing blood products. These products contain antibodies directed to human leukocyte antigens (and subsequently described to nonhuman leukocyte antigens) found on white blood cells. In the intervening 2 decades, other cases not associated with antibodies have been reported as TRALI and an association with passive infusion of lipids accumulated in stored cellular blood products has been made in those cases. This has led to confusion as to what should be considered to constitute TRALI. Therefore, the true incidence of this pulmonary reaction to blood products is currently conjectural at best. Recent consensus development conferences have been held to develop and standardize definitions of TRALI so that epidemiologic and research aspects of this condition can be explored in a scientific manner. These conferences have set out criteria by which TRALI is distinguished from other causes of acute lung injury. This review outlines the widely accepted clinical (mainly pulmonary) features of TRALI, the treatment options, and the excellent long-term prognosis for patients who survive the initial pulmonary insult.

Treatment of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP), characterized by thrombocytopenia and microangiopathic haemolytic anaemia, was almost universally fatal until the introduction of plasma exchange (PE) therapy in the 1970s. Based on clinical studies, daily PE has become the first-choice therapy since 1991. Recent findings may explain its effectiveness, which may include, in particular, the removal of anti-ADAMTS13 autoantibodies and unusually large von Willebrand factor multimers and/or supply of ADAMTS13 in acquired idiopathic or congenital TTP. Based on currently available data, the favoured PE regimen is daily PE [involving replacement of 1-1.5 times the patient's plasma volume with fresh-frozen plasma (FFP)] until remission. Adverse events of treatment are mainly related to central venous catheters. The potential reduction of plasma related side-effects, such as transfusion-related acute lung injury (TRALI) or febrile transfusion reactions by use of solvent-detergent treated (S/D) plasma instead of FFP is not established by controlled clinical studies. Uncontrolled clinical observations and the hypothesis of an autoimmune process in a significant part of the patients with acquired idiopathic TTP suggest a beneficial effect of adjunctive therapy with corticosteroids. Other immunosuppressive treatments are not tested in controlled trials and should be reserved for refractory or relapsing disease. There is no convincing evidence for the use of antiplatelet agents. Supportive treatment with transfusion of red blood cells or platelets has to be evaluated on a clinical basis, but the transfusion trigger for platelets should be very restrictive. Further controlled, prospective studies should consider the different pathophysiological features of thrombotic microangiopathies, address the prognostic significance of ADAMTS13 and explore alternative exchange fluids to FFP, the role of immunosuppressive therapies and of new plasma saving approaches as recombinant ADAMTS13 and protein A immunoadsorption.

Storage of platelet-rich plasma-derived platelet concentrate pools in plasma and additive solution

BACKGROUND

Prestorage pooling of platelet (PLT)-rich plasma (PRP)-derived PLT concentrates (PCs) and storage in either plasma (PS) or an additive solution (AS) is logistically feasible and would result in a product similar to buffy-coat or apheresis PLTs.

STUDY DESIGN AND METHODS

On Day 0, PS PRP PCs were pooled with a sterile connecting device into a new 1.3-L storage container (ELX, PALL Medical). AS-PCs were prepared by addition of a new low-pH glucose-containing AS to the PLT sediment. AS-PCs were pooled into a 1.3-L ELX bag containing four tablets of NaHCO3. PC pools were sampled on Days 1, 5, and 7.

RESULTS

PS pools containing 5 units had a mean PLT yield similar to the AS pools (39 x 10(10) +/- 3 x 10(10) vs. 37 x 10(10) +/- 6 x 10(10); p = 0.25). All pools had WBC counts of less than 1 x 10(6). pH and HCO3 decreased in PS pools with storage, but either increased or remained constant in the AS pools. On Day 7, no differences were seen in morphology score or extent of shape change. Hypotonic shock response was better preserved in the plasma pools (71 +/- 12% vs. 56 +/- 13%, p < 0.01); however, surface P-selectin was expressed less in the AS pools (6 +/- 4% vs. 18 +/- 10%, p < 0.01).

CONCLUSION

Manufacture and storage of PRP-PCs in pools either in plasma or in a glucose-containing AS in this new container are feasible, and there is good preservation of PLT quality to Day 7.

Antibody-induced neutrophil activation as a trigger for transfusion-related acute lung injury in an ex vivo rat lung model

Transfusion-related acute lung injury (TRALI) is a hazardous complication of transfusion and has become the leading cause of transfusion-related death in the United States and United Kingdom. Although leukoagglutinating antibodies have been frequently shown to be associated with the syndrome, the mechanism by which they induce TRALI is poorly understood. Therefore, we reproduced TRALI in an ex vivo rat lung model. Our data demonstrate that TRALI induction by antileukocyte antibodies is dependent on the density of the cognate antigen but does not necessarily require leukoagglutinating properties of the antibody or the presence of complement proteins. Rather, antibody-mediated activation of neutrophils seems to initiate TRALI, a process that could be triggered by neutrophil stimulation with fMLP. Antibody-mediated neutrophil activation and subsequent release of reactive oxygen species may thus represent key events in the pathophysiologic cascade that leads to immune TRALI.