Determination of eicosanoid and cytokine production in salvaged blood, stored red blood cell concentrates, and whole blood

Perioperative Inflammatory Response and Cancer Recurrence in Lung Cancer Surgery: A Narrative Review

While surgical resection is the gold standard treatment for solid tumors, cancer recurrence after surgery is common. Immunosurveillance of remnant tumor cells is an important protective mechanism. Therefore, maintenance of anti-tumor cell activity and proper levels of inflammatory mediators is crucial. An increasing body of evidence suggests that surgery itself and perioperative interventions could affect these pathophysiological responses. Various factors, such as the extent of tissue injury, perioperative medications such as anesthetics and analgesics, and perioperative management including transfusions and methods of mechanical ventilation, modulate the inflammatory response in lung cancer surgery. This narrative review summarizes the pathophysiological mechanisms involved in cancer recurrence after surgery and perioperative management related to cancer recurrence after lung cancer surgery.

Effect of washed versus unwashed red blood cells on transfusion-related immune responses in preterm newborns

Objectives

Transfusion with washed packed red blood cells (PRBCs) may be associated with reduced transfusion‐related pro‐inflammatory cytokine production. This may be because of alterations in recipient immune responses.

Methods

This randomised trial evaluated the effect of transfusion with washed compared with unwashed PRBCs on pro‐inflammatory cytokines and endothelial activation in 154 preterm newborns born before 29 weeks’ gestation. Changes in plasma cytokines and measures of endothelial activation in recipient blood were analysed after each of the first three transfusions.

Results

By the third transfusion, infants receiving unwashed blood had an increase in IL‐17A (P = 0.04) and TNF (P = 0.007), whereas infants receiving washed blood had reductions in IL‐17A (P = 0.013), TNF (P = 0.048), IL‐6 (P = 0.001), IL‐8 (P = 0.037), IL‐12 (P = 0.001) and IFN‐γ (P = 0.001). The magnitude of the post‐transfusion increase in cytokines did not change between the first and third transfusions in the unwashed group but decreased in the washed group for IL‐12 (P = 0.001), IL‐17A (P = 0.01) and TNF (P = 0.03), with the difference between the groups reaching significance by the third transfusion (P < 0.001 for each cytokine).

Conclusion

The pro‐inflammatory immune response to transfusion in preterm infants can be modified when PRBCs are washed prior to transfusion. Further studies are required to determine whether the use of washed PRBCs for neonatal transfusion translates into reduced morbidity and mortality.

Effects of leukoreduction on N-methylhistamine concentration in stored units of canine whole blood

OBJECTIVE

To determine the effects of leukoreduction on N-methylhistamine (NMH; a stable histamine metabolite) concentration in units of canine whole blood during storage and incubation at room temperature (approx 22 °C) to simulate temperature conditions during transfusion.

ANIMALS

8 healthy adult Walker Hounds.

PROCEDURES

A standard unit of blood (450 mL) was obtained from each dog twice, with at least 28 days between donations. Blood units collected from 4 dogs during the first donation underwent leukoreduction, whereas the blood units collected from the other 4 dogs did not undergo leukoreduction, prior to storage at 4 °C. The alternate treatment was applied to blood units collected during the second donation. A sample from each unit was obtained for determination of plasma NMH concentration the day of donation (before and after leukoreduction when applicable) and before and after incubation at room temperature for 5 hours on days 14 and 28 of storage.

RESULTS

Units that underwent leukoreduction had substantially lower leukocyte and platelet counts than nonleukoreduced units. Plasma NMH concentration increased immediately after leukoreduction but did not change significantly during the subsequent 28 days of storage, nor did it differ between units that did and did not undergo leukoreduction.

CONCLUSIONS AND CLINICAL RELEVANCE

Leukoreduction and simulated transfusion temperature did not affect the histamine load in units of canine whole blood during the first 28 days of storage. Further research is necessary to determine whether histamine contributes to the development and severity of blood transfusion reactions in dogs.

Cold-stored leukoreduced CPDA-1 whole blood: in vitro quality and hemostatic properties

BACKGROUND

Some jurisdictions require leukoreduction of cellular blood components. The only whole blood collection set with a platelet-saving filter uses citrate-phosphate-dextrose (CPD) as storage solution. Substituting CPD with citrate-phosphate-dextrose-adenine (CPDA-1) increases shelf life from 21 to 35 days. This would simplify prehospital and rural resupply and reduce wastage. We investigated in vitro quality and hemostatic properties of CPDA-1 whole blood leukoreduced with a platelet-saving filter.

STUDY DESIGN AND METHODS

CPDA-1 whole blood was leukoreduced using a platelet-saving filter and stored 35 days. EDQM requirements, hematology, metabolic parameters, thromboelastography, light transmission aggregometry, fibrinogen, factor VIII, and interleukin-6 were measured on Days 0, 1, 14, 21, and 35 and compared to non-leukoreduced blood.

RESULTS

All units met EDQM requirements. Leukoreduction yielded residual white blood cell count <1 × 10⁶ and 87% platelet recovery on Day 1. It caused reduction in thromboelastography parameters, but not aggregometry response. No hemolysis >0.8% was observed. Factor VIII was higher on Day 35 in the leukoreduced group, 37.9 (95% CI: 26.0, 49.8) versus 13.8 (9.4, 18.2) IU/dL. In both groups, aggregation was significantly reduced by Day 14. Thromboelastography showed remaining platelet activity on Day 35, MA 46.9 (42.1, 51.7) in the leukoreduced and 44.3 (39.6, 49.0) mm in the non-leukoreduced group. Fibrinogen was within reference ranges at Day 35 (>2 g/dL). Interleukin-6 was not detectable.

CONCLUSION

Leukoreducing CPDA-1 whole blood with a platelet-saving filter did not compromise hemostatic properties. We encourage development of a single bag CPDA-1 whole blood collection set with in-line platelet-saving filter.

High Levels of β-Amyloid, Tau, and Phospho-Tau in Red Blood Cells as Biomarkers of Neuropathology in Senescence-Accelerated Mouse

Alzheimer's Disease (AD) is the most common Neurodegenerative Disease (ND), primarily characterised by neuroinflammation, neuronal plaques of β-amyloid (Aβ), and neurofibrillary tangles of hyperphosphorylated tau. α-Synuclein (α-syn) and its heteroaggregates with Aβ and tau have been recently included among the neuropathological elements of NDs. These pathological traits are not restricted to the brain, but they reach peripheral fluids as well. In this sense, Red Blood Cells (RBCs) are emerging as a good model to investigate the biochemical alterations of aging and NDs. Herein, the levels of homo- and heteroaggregates of ND-related proteins were analysed at different stages of disease progression. In particular, a validated animal model of AD, the SAMP8 (Senescence-Accelerated Mouse-Prone) and its control strain SAMR1 (Senescence-Accelerated Mouse-Resistant) were used in parallel experiments. The levels of the aforementioned proteins and of the inflammatory marker interleukin-1β (IL-1β) were examined in both brain and RBCs of SAMP8 and SAMR1 at 6 and 8 months. Brain Aβ, tau, and phospho-tau (p-tau) were higher in SAMP8 mice than in control mice and increased with AD progression. Similar accumulation kinetics were found in RBCs, even if slower. By contrast, α-syn and its heterocomplexes (α-syn-Aβ and α-syn-tau) displayed different accumulation kinetics between brain tissue and RBCs. Both brain and peripheral IL-1β levels were higher in SAMP8 mice, but increased sooner in RBCs, suggesting that inflammation might initiate at a peripheral level before affecting the brain. In conclusion, these results confirm RBCs as a valuable model for monitoring neurodegeneration, suggesting peripheral Aβ, tau, and p-tau as potential early biomarkers of AD.

Red blood cell transfusion and its alternatives in oncologic surgery-A critical evaluation

Although blood transfusions have been used for more than 100 years and their potential to save lives is indisputable, there is still limited data on medium- and long-term outcomes after hemotherapy. Until recently, red blood cell transfusions represented the most commonly employed treatment for cancer anemia. As transfusions have been related to worse patient outcome in oncologic surgery, preventive strategies and alternative treatment approaches in the perioperative setting are warranted. This review aims to evaluate the evidence concerning the impact of transfusion on the course of malignant diseases with a focus on oncologic surgery and to provide a bundle of measures to improve patient care. The perioperative period is pivotal in determining long-term cancer outcome. An increasingly recognized area for improvement during this highly sensitive period is the treatment of anemia for three main reasons: Firstly, anemia has been recognized as an independent predictor of poor prognosis in cancer patients. Secondly, anemia is largely undertreated. Thirdly and probably most importantly, anemia therapy relied and often still relies heavily on red blood cell (RBC) transfusions, which may be an often suboptimal stopgap treatment. Perioperative RBC transfusions should be kept to a minimum due to growing concerns regarding the associated risks, which this review tries to clarify by providing an update of recent literature. This review furthermore discusses treatments for anemia and provides best-practice approaches to improve perioperative management of oncology patients undergoing surgery.

Preoperative anemia and perioperative blood transfusion in head and neck squamous cell carcinoma

OBJECTIVES

To evaluate the impact of preoperative anemia and perioperative blood transfusion (PBT) on disease free (DFS) and overall survival (OS) of patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

Retrospective study of 354 patients primarily treated with surgery between 2006 and 2016. Cases were selected according to completeness and accuracy of available clinical data. Thus, a selection bias cannot be excluded. Patients who received PBT were identified by our controlling department and verified by our blood bank data base.

RESULTS

Both, preoperative anemia and PBT significantly decreased OS in univariate analysis. Although PBT was needed more frequently by older patients in worse physical conditions with more advanced HNSCC, subgroup analysis also demonstrate a profoundly negative effect of PBT on OS in younger patients and early stage HNSCC. According to a restrictive transfusion policy at our hospital the transfusion rate was comparably low. We could not verify increasing effects of PBT on cancer recurrence rates as it was previously shown.

DISCUSSION

Preoperative anemia is the most common paraneoplastic syndrome in HNSCC. Despite its devastating prognostic effect we suggest a restrictive transfusion policy whenever possible. Our data also show that anemia as an independent prognostic factor in head and neck surgical oncology is defined not only by low hemoglobin concentrations but low red blood cell counts as well.

Effect of storage period of red blood cell suspensions on helper T-cell subpopulations

BACKGROUND

The aim of this study was to investigate the immunological alterations that occur during the storage of erythrocyte suspensions which may lead to transfusion-related immunomodulation following allogeneic blood transfusion.

MATERIALS AND METHODS

One part of the erythrocyte suspensions obtained from donors was leucoreduced while the other part was not. The leucoreduced (LR) and non-leucoreduced (NL) erythrocyte suspensions were then further divided into three equal amounts which were stored for 0, 21 or 42 days prior to measurements, by enzyme-linked immunosorbent assays, of cytokine levels in their supernatants. T-helper (Th) lymphocyte subgroups and gene expression were analysed in the NL erythrocyte suspensions by flow cytometry and real-time polymerase chain reaction, respectively. Results were compared to those of storage day 0.

RESULTS

By day 21, the number of Th2 cells had increased significantly and the numbers of Th1, Th22 and Treg cells had decreased significantly in the NL erythrocyte suspensions. On day 42 the numbers of Th2 and Treg cells in the NL suspensions were significantly increased while the number of Th1 cells was significantly decreased. The levels of transcription factors (TBX21, GATA3, and SPI.1) were significantly decreased on days 21 and 42, and AHR, FOXP3 and RORC2 levels were significantly increased on day 42 in NL erythrocyte suspensions. The decrease in interleukin-22 and increase in transforming growth factor-β levels found in NL erythrocyte suspensions on day 21 were statistically significant. Elevated levels of interleukin-17A were found in both LR and NL erythrocyte suspensions on day 42.

DISCUSSION

Our results suggest that allogeneic leucocytes and cytokines may play significant roles in the development of transfusion-related immunomodulation.

Perioperative red blood cell transfusion in orofacial surgery

In the field of orofacial surgery, a red blood cell transfusion (RBCT) is occasionally required during double jaw and oral cancer surgery. However, the question remains whether the effect of RBCT during the perioperative period is beneficial or harmful. The answer to this question remains challenging. In the field of orofacial surgery, transfusion is performed for the purpose of oxygen transfer to hypoxic tissues and plasma volume expansion when there is bleeding. However, there are various risks, such as infectious complications (viral and bacterial), transfusion-related acute lung injury, ABO and non-ABO associated hemolytic transfusion reactions, febrile non-hemolytic transfusion reactions, transfusion associated graft-versus-host disease, transfusion associated circulatory overload, and hypersensitivity transfusion reaction including anaphylaxis and transfusion-related immune-modulation. Many studies and guidelines have suggested RBCT is considered when hemoglobin levels recorded are 7 g/dL for general patients and 8-9 g/dL for patients with cardiovascular disease or hemodynamically unstable patients. However, RBCT is occasionally an essential treatment during surgeries and it is often required in emergency cases. We need to comprehensively consider postoperative bleeding, different clinical situations, the level of intra- and postoperative patient monitoring, and various problems that may arise from a transfusion, in the perspective of patient safety. Since orofacial surgery has an especially high risk of bleeding due to the complex structures involved and the extensive vascular distribution, measures to prevent bleeding should be taken and the conditions for a transfusion should be optimized and appropriate in order to promote patient safety.

The role of endothelium in the onset of antibody-mediated TRALI

Transfusion Related Acute Lung Injury (TRALI) is one of the leading causes of mortality and morbidity following blood transfusion. The mechanisms behind the disease are not yet fully understood but seem to involve many different activating pathways and donor factors, in synergy with patient susceptibility. Studies have focused mostly on neutrophil activation, as aggregates of neutrophils and edema in lungs are found in post-mortem histological sections. This review aims to highlight the role of the endothelium in TRALI, as activated endothelium is the main promoter of leukocyte transmigration, and creates the barrier between blood and tissue. Since recent evidence suggests that a strong endothelial barrier prevents leukocyte transmigration and vascular leakage, we suggest that strengthening this barrier may be key to TRALI prevention.

Balance Between the Proinflammatory and Anti-Inflammatory Immune Responses with Blood Transfusion in Sepsis

Blood product transfusion may exacerbate the initial immunosuppressive response of sepsis. Nurses and other patient care providers must be diligent in recognizing and managing a worsening immune status, using flow cytometry to monitor patients' immune status. This type of monitoring may be instrumental in reducing morbidity and mortality in persons with sepsis. This article discusses the recent literature on the associated inflammatory responses that occur with blood transfusion and provides an analysis of alterations in key inflammatory pathways in response to transfusion in a sepsis population.

Transfusion-related immunomodulation and cancer

Blood and blood-component therapy triggers immunological reactions in recipients. Transfusion-related immunomodulation [TRIM] is an important complex biological immune reaction to transfusion culminating in immunosuppression. The mechanisms underlying TRIM include the presence of residual leukocytes and apoptotic cells, the transfusion of immunosuppressive cytokines either present in donor components or generated during blood processing, the transfer of metabolically active growth factor-loaded microparticles and extracellular vesicles and the presence of free hemoglobin or extracellular vesicle-bound hemoglobin. TRIM variables include donor-specific factors as well as processing variables. TRIM may explain, at least in part, the controversial negative clinical outcomes observed in cancer patients receiving transfusion in the context of curative-intent surgeries. The use of novel technologies including metabolomics and proteomics on stored blood may pave the way for a deeper understanding of TRIM in general and its impact on cancer progression.

Effects of Leukoreduction and Storage on Erythrocyte Phosphatidylserine Expression and Eicosanoid Concentrations in Units of Canine Packed Red Blood Cells

Background

Storage of canine packed red blood cells (pRBCs) can increase erythrocyte phosphatidylserine (PS) expression and eicosanoid concentrations.

Hypothesis/Objectives

To determine the effects of leukoreduction on erythrocyte PS expression and eicosanoid concentrations in stored units of canine pRBCs. Our hypothesis was that leukoreduction would decrease PS expression and eicosanoid concentrations.

Animals

Eight healthy dogs.

Methods

In a cross‐over study, units of whole blood were leukoreduced (LR) or non‐LR and stored (10 and 21 days) as pRBCs. Samples were collected at donation, and before and after a simulated transfusion. PS expression was measured by flow cytometry, and concentrations of arachidonic acid (AA), prostaglandin F_2α (PGF_2α), prostaglandin E₂ (PGE₂), prostaglandin D₂ (PGD₂), thromboxane B₂ (TXB₂), 6‐keto‐prostaglandin F_1α (6‐keto‐PGF_1α), and leukotriene B₄ (LTB₄) were quantified by liquid chromatography–mass spectrometry.

Results

There was no change in PS expression during leukoreduction, storage, and simulated transfusion for non‐LR and LR units. Immediately after leukoreduction, there was a significant increase in TXB₂ and PGF_2α concentrations, but during storage, these eicosanoids decreased to non‐LR concentrations. In both LR and non‐LR units, 6‐keto‐PGF_1α concentrations increased during storage and simulated transfusion, but there was no difference between unit type. There was no difference in AA, LTB₄, PGE₂, and PGD₂ concentrations between unit types.

Conclusions and Clinical Importance

Leukoreduction, storage, and simulated transfusion do not alter erythrocyte PS expression. Leukoreduction causes an immediate increase in concentrations of TXB₂ and PGF_2α, but concentrations decrease to non‐LR concentrations with storage. Leukoreduction does not decrease the accumulation of 6‐keto‐PGF_1α during storage.

Evaluation of eicosanoid concentrations in stored units of canine packed red blood cells

OBJECTIVE To evaluate eicosanoid concentrations in freshly prepared canine packed RBCs (PRBCs) and to assess changes in eicosanoid concentrations in PRBC units over time during storage and under transfusion conditions. DESIGN Prospective study. SAMPLE 25 plasma samples from 14 healthy Greyhounds. PROCEDURES Plasma samples were obtained during PRBC preparation (donation samples), and the PRBC units were then stored at 4°C until used for transfusion (≤ 21 days later; n = 17) or mock transfusion if expired (22 to 24 days later; 8). Immediately prior to use, 100 mL of saline (0.9% NaCl) solution was added to each unit and a pretransfusion sample was collected. A posttransfusion sample was collected after transfusion or mock transfusion. Concentrations of arachidonic acid, prostaglandin (PG) F_2α, PGE₂, PGD₂, thromboxane B₂, 6-keto-PGF_1α, and leukotriene B₄ were measured by liquid chromatography-mass spectrometry and analyzed statistically. RESULTS Median arachidonic acid concentration was significantly decreased in posttransfusion samples, compared with the concentration in donation samples. Median PGF_2α, 6-keto-PGF_1α, and leukotriene B₄ concentrations were significantly increased in pretransfusion samples, compared with those in donation samples. Median PGF_2α, thromboxane B₂, and 6-keto-PGF_1α concentrations were significantly increased in posttransfusion samples, compared with those in pretransfusion samples. Duration of PRBC storage had significant associations with pretransfusion and posttransfusion arachidonic acid and thromboxane B₂ concentrations. CONCLUSIONS AND CLINICAL RELEVANCE Concentrations of several proinflammatory eicosanoids increased in PRBC units during storage, transfusion, or both. Accumulation of these products could potentially contribute to adverse transfusion reactions, and investigation of the potential association between eicosanoid concentrations in PRBCs and the incidence of transfusion reactions in dogs is warranted.

Leucoreduction of blood components: an effective way to increase blood safety?

Over the past 30 years, it has been demonstrated that removal of white blood cells from blood components is effective in preventing some adverse reactions such as febrile non-haemolytic transfusion reactions, immunisation against human leucocyte antigens and human platelet antigens, and transmission of cytomegalovirus. In this review we discuss indications for leucoreduction and classify them into three categories: evidence-based indications for which the clinical efficacy is proven, indications based on the analysis of observational clinical studies with very consistent results and indications for which the clinical efficacy is partial or unproven.

Release of cytokines in stored whole blood and red cell concentrate: Effect of leukoreduction

Background:

Storage time of blood components plays a major role in the accumulation of cytokines causing adverse transfusion reactions.

Aims:

The aim was to study the trend in the levels of interleukin-6 (IL-6), IL-8, tumor necrosis factor-alpha (TNF-α) and regulated upon activation, normal T-cells expressed and secreted (RANTES) during storage of whole blood (WB) and red cell concentrate (RCC) and to study the effect of leukoreduction (LR).

Materials and Methods:

WB sample was taken on 0, 7, 14, 21, and between 28 and 35 days and plasma aliquots were frozen. Samples from RCC and buffy-coat depleted RCC prepared using Optipress II were collected on 0, 7, 14, 21 and between 28 and 35 days. Cytokine estimation was done using ELISA development kits. Normal range of cytokines was established using 0 day samples of WB. Statistical analysis was done using nonparametric tests.

Results and Conclusion:

The normal range of IL-6 was 0-23 pg/ml, IL-8 0-12 pg/ml, TNF-α 0-3 pg/ml, and RANTES 1200-2000 pg/ml. IL-6 was in normal range and showed a decreasing trend during storage. IL-8 levels increased significantly from 0 to 35 days. In RCC, the highest level was 480 pg/ml on 28^th day. It was in the normal range in buffy-coat depleted RCC up to 28 days. RANTES level was significantly low in buffy-coat depleted RCC compared to RCC. We conclude that WB has high levels of IL-8 and RANTES. The levels of cytokines are affected by storage period and LR. Comparison of WB and buffy-coat depleted RCC shows significantly low levels of IL-6, IL-8, and RANTES in buffy-coat depleted RCC. This study emphasizes the use of red cell components instead of WB and buffy-coat depleted RCC instead of RCC.

Inflammatory response, immunosuppression, and cancer recurrence after perioperative blood transfusions

Debate on appropriate triggers for transfusion of allogeneic blood products and their effects on short- and long-term survival in surgical and critically ill patients continue with no definitive evidence or decisive resolution. Although transfusion-related immune modulation (TRIM) is well established, its influence on immune competence in the recipient and its effects on cancer recurrence after a curative resection remains controversial. An association between perioperative transfusion of allogeneic blood products and risk for recurrence has been shown in colorectal cancer in randomized trials; whether the same is true for other types of cancer remains to be determined. This article focuses on the laboratory, animal, and clinical evidence to date on the mechanistic understanding of inflammatory and immune-modulatory effects of blood products and their significance for recurrence in the cancer surgical patient.

Blood transfusion and cytokines' changes in total knee replacement

INTRODUCTION

The aim of this prospective comparative study was to evaluate the serum levels of different cytokines and the frequency of adverse reactions and wound infections in patients who underwent total knee replacement (TKR) and were not transfused or received either allogeneic blood transfusion or postoperative auto-transfusion (PAT) with unwashed shed blood.

MATERIALS AND METHODS

A total of 248 patients were categorized into three groups; in Group 0 (n 85) patients received no blood transfusion, in Group 1 (n 92) patients received PAT and in Group 2 (n 71) patients received allogeneic blood transfusion. Patient's demographic and clinical data including age, gender, body mass index, preoperative haemoglobin value, adverse reactions and complications were documented. The serum levels of IL-1b, IL-6, IL-8, IL-10 and TNF were measured preoperatively, and on the first, third and fifth postoperative day. A statistical analysis of the results was performed.

RESULTS

A significant elevation of cytokine values were observed during the first five postoperative days in patients who received blood transfusion after TKR. Adverse reactions (chills and pyrexia) were also more common in patients who received blood transfusion, whereas superficial infections were more common in patients who received allogeneic blood transfusion.

CONCLUSION

The immunological status-as expressed by the measured cytokine levels-is altered in patients receiving blood transfusion compared to patients receiving no blood transfusion during the first five postoperative days. PAT is preferable to allogeneic blood transfusion in terms of the rate of adverse reactions and superficial wound infections.

Specific requirements for bloodless cardiopulmonary bypass in neonates and infants; a review

A miniaturized cardiopulmonary bypass circuit enables the safe performance, in selected pediatric patients, of bloodless open heart surgery. As the latest survival rates in neonatal and infant cardiac surgery have become satisfactory, investigators have concentrated upon the improvement of existing procedures. Institutional guidelines and multidisciplinary efforts undertaken in the pre- and postoperative periods are of great importance, concerning bloodless CPB and should be seriously pursued by all involved caregivers.

This review reflects upon the selective, most relevant requirements for success of asanguinous neonatal and infant CPB: acceptable level of hemodilution during the CPB, patient preoperative hematocrit value and volume of CPB circuit. We present an assessment of practical measures that were also adapted in our institution to achieve an asanguinous CPB for neonatal and infant patients.

TRALI--definition, mechanisms, incidence and clinical relevance

Transfusion-related acute lung injury (TRALI) is defined as new acute lung injury (ALI) that occurs during or within six hours of transfusion, not explained by another ALl risk factor. Transfusion of part of one unit of any blood product can cause TRALI. The mechanism may include factors in unit(s) of blood, such as antibody and biologic response modifiers. In addition, yet to be described factors in a patient's illness may predispose to the condition. The current incidence is estimated to be 1 in 5000 units. Patients present with acute dyspnea, or froth in the endotracheal tube in intubated patients. Hypertension, hypotension, acute leukopenia have been described. Management is similar to that for ALI and is predominantly supportive. When TRALI is suspected, Blood banks should be notified to quarantine other components from the same donation. No special blood product is required for subsequent transfusion of a patient who has developed TRALI.

Effects of Circuit Miniaturization in Reducing Inflammatory Response to Infant Cardiopulmonary Bypass by Elimination of Allogeneic Blood Products

Conventional neonatal cardiopulmonary bypass requires the use of large volumes of allogeneic blood to prevent unacceptable hemodilution. Evidence is accumulating to suggest that the use of blood products during cardiopulmonary bypass has a negative effect on clinical recovery through inflammatory side effects. This would suggest an advantage for eliminating blood use in infant cardiopulmonary bypass through circuit miniaturization. In this article, we review the data supporting this rationale and provide the results from studies in our laboratory that emphasize the benefits of circuit miniaturization.

Complement activation in prestorage leucocyte-filtered plasma

Complement activation and generation of pro-inflammatory cytokines occur during storage of blood components. Prestorage leucocyte filtration of platelet concentrates and red cells diminishes the accumulation of leucocyte-derived cytokines during storage, however, transfusion reactions are not eliminated. We investigated inflammatory mediator release during storage of plasma and whole blood and the effect of prestorage leucocyte filtration of plasma. Twenty-four blood units were collected from healthy blood donors and stored for 35 days. Eight units were stored as whole blood, eight units as plasma and eight units as prestorage filtered plasma. Samples were collected weekly for analyses of potassium, leucocytes, free plasma haemoglobin, complement activation (C3a and SC5b-9) and pro-inflammatory cytokines [interleukin (IL)-6, IL-8 and tumor necrosis factor (TNF)-alpha]. Elevated levels of C3a and SC5b-9 were registered in filtered plasma, from the beginning of storage. C3a levels increased during storage. There was a higher rate of change during storage in C3a (P < 0.01) and SC5b-9 (P < 0.05) in plasma compared with filtered plasma. Interleukin (IL)-8 is released in whole blood. The cytokine levels generated in plasma and filtered plasma were low. Complement activation is present in whole blood, plasma and filtered plasma during storage. Prestorage filtration of plasma activates the complement cascade but does not influence cytokine generation.

Transfusion of post-operative shed blood: laboratory characteristics and clinical utility

Increased awareness of the potential hazards of allogenic blood transfusion, such as incompatibility reactions, metabolic and immunologic disorders, or transmission of viral diseases, has led to an emphasis on allogeneic blood alternatives. For orthopaedic surgery, several autologous transfusion modalities have emerged as alternatives to allogeneic blood transfusion, avoiding its immunomodulatory effects. Among them, transfusion or return of post-operative salvaged shed blood has become popular in major orthopaedic procedures. However, although the effectiveness of this blood-saving method is well documented, several authors have questioned its safety and recommended the use of washed blood. Therefore, this review analyses the haematologic characteristics of unwashed filtered shed blood, including metabolic status and survival of red blood cells, the components of the haemostatic system, the content of fat particles, bacterial and tumour cells and the possibility of their removal, the content of inflammatory mediators, and the effects on the patient's immune system. From data reviewed in this paper, it can be concluded that post-operative salvage of blood seems to be an excellent source of functional and viable red cells without many of the transfusion-related risks and with some immuno-stimulatory effects. In addition, from our experience, post-operative re-infusion of unwashed shed blood after major spine procedures has proved to reduce post-operative homologous transfusion requirements and to complement pre-operative autologous blood donation, without any clinically relevant complication.

Effect of autologous salvaged blood on postoperative natural killer cell precursor frequency

BACKGROUND

Immunosuppression after major surgery increases the risk of infections. Natural killer cells play a pivotal part in defence against infection. We aimed to investigate the immunomodulatory effects of different types of postoperative blood transfusion by use of a new assay for measuring the frequency of peripheral blood natural killer precursor cells (NKpf assay).

METHODS

We measured the natural killer cell precursor (NKp) frequency before and 5 days after surgery in 120 patients undergoing joint replacement surgery. The patients were assigned to one of five groups according to the type of transfusion received: non-transfused (n=32), allogeneic non-leukodepleted blood (eight), allogeneic leukodepleted blood (30), autologous predeposited blood (ten), and autologous salvaged blood collected within the first 24 h after surgery (40). We also measured interferon gamma and interleukin 10 concentrations before and after surgery.

FINDINGS

The mean postoperative NKp frequency for all patients was lower than the preoperative values, except in patients receiving autologous salvaged blood, which was higher than all other groups (p<0.0001). Postoperative NKp frequencies for patients receiving allogeneic or autologous predeposited blood responded similarly (p=0.99), but these patients had lower NKp frequencies than did the non-transfused group (p<0.0001). Postoperative interferon gamma concentrations were higher in the autologous salvaged blood group (p<0.0001) than in other groups, which did not differ from each other. Interleukin 10 concentrations were similar across all groups (p=0.49).

INTERPRETATION

Immunosuppression associated with surgery and blood loss was reflected in a reduced frequency of NKp and decreased interferon gamma. This immunosuppression was reversed by transfusion of autologous salvaged blood, suggesting that this fluid contained immunostimulants.

Immune response to autologous transfusion in healthy volunteers: WB versus packed RBCs and FFP

BACKGROUND

Storage of blood as packed RBCs and FFP is standard practice in allogeneic transfusion. Separation into components has been proposed for autologous transfusion, as well, but beneficial effects have not yet been shown.

STUDY DESIGN AND METHODS

Twenty-four healthy male volunteers were randomly assigned to receive 1 unit of either autologous RBCs and FFP (RCP group) or WB (WB group) after 49 or 35 days of storage, respectively. The immune response was analyzed by ELISA for IL-6, C3a, terminal complement complex SC5b-9, TNF-alpha, and neopterin. Differential WBC counts and the phagocytosis of neutrophils and monocytes were measured by flow cytometry.

RESULTS

Cell counts of monocytes (0.85 x 10(3) ng/microL) [corrected] and neutrophils (6.9 x 10(3) ng/microL) [corrected] increased 30 minutes after WB transfusion and then returned to close to the baseline values seen in the RCP group (0.47 and 2.9 x 10(3) ng/microL [corrected], respectively) throughout the monitored period (p<0.05). C3a (169 vs. 116 ng/microL) [corrected] and IL-6 (29 vs. 6 pg/mL) reached higher plasma concentrations in the WB group (n = 11) than in the RCP group (n = 10). Phagocytosis of opsonized Escherichia coli was increased in neutrophils and monocytes and lasted up to 7 days after the transfusion of whole blood.

CONCLUSION

Autologous WB induces a modest immunomodulation, but this effect is not observed upon transfusion of autologous blood components.