Transfusion as an Inflammation Hit: Knowns and Unknowns

Skin boosters: Definitions and varied classifications

BACKGROUND

The concept of "skin boosters" has evolved, marking a shift from traditional uses of hyaluronic acid (HA) fillers primarily for augmenting skin volume to a more diverse application aimed at improving dermal conditions. Restylane Vital and other HA fillers have been repurposed to combat skin aging and wrinkles by delivering HA directly to the dermis.

OBJECTIVES

This review aims to define the term "skin booster" and to discuss the various components that constitute skin boosters. It seeks to provide a comprehensive overview of the different ingredients used in skin boosters, their roles, and their impact on enhancing dermal conditions.

METHODS

A comprehensive review was conducted, focusing on representative skin booster ingredients. The approach involved analyzing the different elements used in skin boosters and their specific roles in enhancing dermal improvement.

RESULTS

The findings indicate that skin boosters, encompassing a range of ingredients, are effective in improving the condition of the skin's dermis. The review identifies key ingredients in skin boosters and their specific benefits, including hydration, elasticity improvement, and wrinkle reduction.

CONCLUSIONS

Skin boosters represent a significant development in dermatological treatments, offering diverse benefits beyond traditional HA fillers. This review provides valuable insights into the constituents of skin boosters and their effectiveness, aiding readers in making informed decisions about these treatments. The potential of skin boosters in dermatological practice is considerable, warranting further research and application.

Bleeding in acute coronary syndrome: from definitions, incidence, and prognosis to prevention and management

INTRODUCTION

In patients with acute coronary syndrome (ACS), the ischemic benefit of antithrombotic treatment is counterbalanced by the risk of bleeding. The recognition that bleeding events have prognostic implications (i.e. mortality) similar to recurrent ischemic events led to the development of treatment regimens aimed at balancing both ischemic and bleeding risks.

AREAS COVERED

This review aims at describing definitions, incidence, and prognosis related to bleeding events in ACS patients as well as bleeding-avoidance strategies for their prevention and management of bleeding complications.

EXPERT OPINION

Management of ACS patients has witnessed remarkable progress after the shift in focusing on the trade-off between ischemia and bleeding. Efforts in standardizing bleeding definitions will allow for better defining the prognostic impact of different types of bleeding events and enable to identify the high-bleeding risk patient. Such efforts will allow to balance the trade-off between the thrombotic and bleeding risk of the individual patient translating into better downward diagnostic and therapeutic decision-making. Novel strategies aiming at maximizing the safety and efficacy of antithrombotic regimens as well as the development of novel antithrombotic drugs and reversal agents and technological advances will allow for optimization of bleeding-avoidance strategies and management of bleeding complications.

Effect of intraoperative blood transfusion on inflammatory response in parturients with placenta previa undergoing cesarean section: A prospective observational study

Background

The neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), and red cell distribution width (RDW) have been reported as useful biomarkers for evaluating inflammation and a predictor of surgical prognosis. Although there have been recent reports that transfusion may affect inflammatory responses, studies on the post-transfusion inflammatory response in parturients are rare. Therefore, this study aimed to observe changes in inflammatory response after transfusion during cesarean section (C-sec) through NLR, PLR, and RDW.

Methods

Parturients aged 20-50 years who underwent C-sec under general anesthesia due to placenta previa totalis from March 4, 2021, to June 10, 2021 were participated in this prospective observational study. We compared postoperative NLR, PLR, and RDW between the transfusion and non-transfusion groups.

Results

A total of 53 parturients were included in this study, of which 31 parturients received intraoperative transfusions during C-sec. There were no significant difference in preoperative NLR (3.6 vs. 3.4, p = 0.780), PLR (132.8 vs. 111.3, p = 0.108), and RDW (14.2 vs. 13.6, p = 0.062) between the two groups. However, postoperative NLR was significantly higher in the transfusion group than in the non-transfusion group (12.2 vs. 6.8, p < 0.001). Postoperative RDW was significantly higher in the transfusion group than in the non-transfusion group (14.6 vs. 13.9, p = 0.002) whereas postoperative PLR was not significantly different between the two groups (108.0 vs. 117.4, p = 0.885).

Conclusions

Postoperative NLR and RDW, the inflammatory biomarkers, were significantly higher in the transfused C-sec parturients. These results suggest a significant association between postoperative inflammatory response and transfusion in obstetric practice.

Anemia Recovery after Trauma: A Longitudinal Study

Background: Post-injury inflammation and its correlation with anemia recovery after severe trauma is poorly described. Severe injury induces a systemic inflammatory response associated with critical illness and organ dysfunction, including disordered hematopoiesis, and anemia. This study sought to characterize the resolution of post-injury inflammation and anemia to identify risk factors associated with persistence of anemia. Patients and Methods: This single-institution study prospectively enrolled 73 trauma patients with an injury severity score >15, hemorrhagic shock, and a lower extremity long bone orthopedic injury. Blood was obtained at enrollment and after 14 days, one, three, and six months. Analytes were compared using Mann-Whitney U tests with correction for multiple comparisons. Results: Median age was 45 years and Injury Severity Score (ISS) was 27, with anemia rates of 97% at two weeks, 80% at one month, 52% at three months, and 30% at six months. Post-injury elevations in erythropoietin, interleukin-6, and C-reactive protein resolved by one month, three months, and six months, respectively. Median granulocyte colony-stimulating factor (G-CSF) and tumor necrosis factor (TNF)-α concentrations remained elevated throughout the six-month follow-up period. Patients with persistent anemia had longer intensive care unit and hospital lengths of stay, more infectious complications, and received more packed red blood cell transfusions compared to those with early anemia recovery. Conclusions: Severe trauma is associated with a prolonged inflammatory response, which is associated with increased transfusion requirements, lengths of stay, and persistent anemia. Further analysis is needed to identify correlations between prolonged inflammation and clinical outcomes after discharge.

Increased severe primary graft dysfunction in left ventricular assist device patients following united network for organ sharing allocation changes

INTRODUCTION

In 2018, the United Network for Organ Sharing (UNOS) implemented a new heart allocation system which prioritized patients on temporary support devices and left-ventricular assist device (LVAD) patients with complications. These changes have the potential to impact outcomes for patients bridged to transplant with an LVAD.

METHODS

We performed a retrospective study of 168 adult heart transplant recipients at our center between 2016 and 2020 evaluating post-transplant outcomes before and after UNOS allocation changes. Donor and recipient data were retrieved from chart review and national databases. The primary outcome of this study was severe primary graft dysfunction (PGD) with secondary outcomes of 30-day readmission, 30-day mortality, and 1-year mortality.

RESULTS

Incidence of severe PGD was similar in the overall cohort before and after the changes (10% vs. 15%, respectively, p = .3) and increased in the LVAD-bridged cohort (12% vs. 40%, respectively, p < .01). Secondary outcomes of readmission and survival were similar between all groups. Blood transfusion was predictive of severe PGD in multivariable modeling (OR 1.3 [1.11-1.59], p < .01).

Rectus Plication Does Not Increase Risk of Thromboembolic Events Following Abdominal Body Contouring: A Matched Case-Control Analysis

BACKGROUND

Rectus abdominis plication increases intra-abdominal pressure and lower-extremity venous stasis, which may increase the incidence of venous thromboembolism (VTE) events.

OBJECTIVES

The aim of this study was to investigate the potential association between VTE and rectus abdominis muscle plication during surgery.

METHODS

A retrospective review of all patients who underwent abdominal body contouring at the authors' institution between 2010 and 2020 was completed. Cases were those with postoperative VTEs and were matched to controls (1:4) via potential confounders. Variables collected include demographic data, operative details, comorbidities, and postoperative complications. Statistical analysis was performed with parametric, nonparametric, and multivariable regression modeling.

RESULTS

Overall, 1198 patients were included; 19 (1.59%) experienced a postoperative VTE and were matched to 76 controls. The overall cohort was 92.7% female with an average age of 44 years, an average Charlson Comorbidity Index of 1 point, and an average BMI of 30.1 kg/m2. History of cerebrovascular events (14.5% vs 36.8%, P = 0.026) differed significantly between cohorts, but no significant associations were noted in all other baseline demographics. Additionally, VTE cases were more likely to have received intraoperative blood transfusions (odds ratio = 8.4, P = 0.04). Bivariate analysis demonstrated cases were significantly more likely to experience concurrent complications, including delayed wound healing (0% vs 5.3%, P = 0.044), seroma formation (5.3% vs 21.1%, P = 0.027), and fat necrosis (0% vs 5.3%, P = 0.044). However, these findings were not significant in a multivariable regression model. Plication was not associated with VTE outcomes.

CONCLUSIONS

Rectus plication does not increase the risk of VTE. However, the odds of VTE are significantly increased in patients who received intraoperative blood products compared with those who did not.

LEVEL OF EVIDENCE: 3

Cell saver blood transfusions may be associated with a decrease in inflammation and improved outcome measures in pediatric cardiac surgery patients

OBJECTIVE

Cardiopulmonary bypass (CPB) is a requisite for correction of congenital heart disease by open-heart surgery and induces a systemic inflammatory response that can lead to complications such as acute lung injury and acute kidney injury. In addition, blood transfusions are commonly required for this type of surgery, and they may further exacerbate this inflammatory response and increase morbidity and mortality. We hypothesized that, in contrast to red blood cells, intraoperative cell saver (CS) blood transfusions attenuate the post-CPB proinflammatory cytokine response.

METHODS

Serum cytokine concentrations of IL-10, IL-1RA, IL-6, IL-8, and TNF-α were measured at four time points (preoperatively and postoperatively on postoperative days 0, 1, and 2).

RESULTS

Anti-inflammatory IL-10 levels were significantly lower in the CS group on POD 0 than in the control group (mean 1083.2 pg/mL vs 2080.2 pg/mL, 95%CI 357.4-1636.6, p = .0026). Of the clinical parameters measured, mean BUN and creatinine levels on POD 2 were significantly lower in the CS group (13.79 vs 21.88, p = .004 and 0.45 vs 0.55, p = .055, respectively). In addition, the duration of milrinone use decreased by 80% in the CS group (0.20, 95%CI 0.04, 0.94; p = .048), the median time to extubation in hours was significantly lower in the CS group (3.5 vs 6.5; 95%CI -38.00, -0.50; p = .026), and hospital length of stay was decreased by 60% in the CS group (p = .003).

CONCLUSIONS

CS transfusions in children may lower postoperative anti-inflammatory IL-10 levels, possibly due to an overall decrease in proinflammatory state, and may be associated with improvements in renal and pulmonary functions.

Increased risk of suicide attempt among patients receiving blood transfusion: A propensity matched analysis

To examine whether the association between blood transfusion and suicide attempt exists.Utilizing the national insurance database from Taiwan and propensity score matching analysis, the incidence of suicide attempt in a cohort with blood transfusion versus controls was compared.The key finding is that higher incidence of suicide attempt in blood transfusion than control group (with an adjusted hazard ratio of 1.79 with 95% confidence interval, 1.72-1.88) after adjusted for the covariates.Patients receiving blood transfusion are an increased risk of subsequent suicide attempt.

Hemoglobin matters: Perioperative blood management for oncology patients

As the number of cancer cases rise each year in Canada, so does the number of surgical oncology cases. Surgery presents a unique and heightened stressor for the body already experiencing volatility from factors such as disease and treatments. Perioperative red blood cell (RBC) transfusions are critical to stabilize hemoglobin levels and correct anemia, as well as provide a buffer against anticipated intraoperative blood loss. Thoroughly examining and anticipating risk factors related to the potential need for perioperative blood transfusions is necessary to improve outcomes. Research evidence in recent years related to perioperative blood management of oncology patients has specifically recommended active, coordinated programs to reduce the need and amount of blood transfusions administered pre-, intra-, and post-surgery. Coordination between surgical oncologists and a local or provincial patient blood management (PBM) program is an important strategy that allows patients at risk of perioperative complications to be identified and receive early interventions and ongoing observation.

L’importance de l’hémoglobine : gestion périopératoire du sang pour les patients en oncologie

Au Canada, le nombre de cas de cancer augmente chaque année et, par conséquent, le nombre de patients en oncologie qui subissent une opération. La chirurgie cause un stress particulièrement intense à l’organisme déjà fragilisé par la maladie et les traitements. Les transfusions périopératoires de globules rouges sont essentielles pour stabiliser le taux d’hémoglobine et soigner l’anémie, ainsi que pour gérer la perte de sang attendue pendant l’opération. Il est nécessaire d’examiner en profondeur et d’anticiper les facteurs de risque associés aux transfusions sanguines périopératoires pour améliorer le devenir des patients. Ces dernières années, la recherche sur la gestion périopératoire du sang des patients en oncologie recommande tout spécialement la création de programmes d’intervention coordonnés pour réduire la nécessité et le nombre de transfusions sanguines administrées avant, pendant et après l’opération. Pour recenser les patients à risque de complications périopératoires et leur faire bénéficier d’interventions rapides et d’une observation continue, la bonne stratégie est de mettre en lien les chirurgiens oncologues avec un programme local ou provincial de conservation du sang.

The Use of Screening Algorithm to Defer Blood Donors with Subclinical Malaria

Plasmodium falciparum infection in blood donors is common in malaria endemic countries, including Ghana. To date, there are no established exclusion criteria to defer a donor carrying malaria parasites. Therefore, based on significant independent variables identified in this study, donor malaria screening algorithm was developed to be used by blood banks to screen blood donors for subclinical malaria. Each significant variable was weighted one (1) point and its alternative response was weighted negative one (-1) point. Accumulation of the points determines the risk level of the donor. These weighted points were used to categorize infected donors as having negligible (<2 points), tolerable (3-4 points), undesirable (5-8 points), or intolerable (>9 points) risk. Based on accumulated weight of ≥5 points, the algorithm was 94.7% (54/57) sensitive but 82% (298/364) specific. With this level of specificity, 18% of the blood donors without malaria would have been deferred. Therefore, it is imperative that all donors with accumulated risk ≥5 be screened for malaria using either malaria rapid test kit or microscopy.

Effects and Side Effects of Platelet Transfusion

Aside from their canonical role in hemostasis, it is increasingly recognized that platelets have inflammatory functions and can regulate both adaptive and innate immune responses. The main topic this review aims to cover is the proinflammatory effects and side effects of platelet transfusion. Platelets prepared for transfusion are subject to stress injury upon collection, preparation, and storage. With these types of stress, they undergo morphologic, metabolic, and functional modulations which are likely to induce platelet activation and the release of biological response modifiers (BRMs). As a consequence, platelet concentrates (PCs) accumulate BRMs during processing and storage, and these BRMs are ultimately transfused alongside platelets. It has been shown that BRMs present in PCs can induce immune responses and posttransfusion reactions in the transfusion recipient. Several recent reports within the transfusion literature have investigated the concept of platelets as immune cells. Nevertheless, current and future investigations will face the challenge of encompassing the immunological role of platelets in the scope of transfusion.

Blood transfusion in major emergency abdominal surgery

BACKGROUND

Major emergency abdominal surgery is associated with excess mortality. Transfusion is known to be associated with increased morbidity and emergency surgery is an independent risk factor for perioperative transfusion. The primary objectives of this study were to identify risk factors for transfusion, and secondarily to investigate the influence of transfusion on clinical outcomes after major emergency abdominal surgery.

STUDY DESIGN AND METHODS

This study combined retrospective observational data including intraoperative, postoperative, and transfusion data in patients undergoing major emergency abdominal surgery from January 2010 to October 2016 at a Danish university hospital. The primary outcome was a transfusion of any kind from initiation of surgery to postoperative day 7. Secondary outcomes included 7-, 30-, 90-day and long-term mortality (median follow-up = 34.6 months, IQR = 13.0-58.3), lengths of stay, and surgical complication rate (Clavien-Dindo score ≥ 3a).

RESULTS

A total of 1288 patients were included and 391 (30%) received a transfusion of any kind. Multivariate logistic regression identified age, hepatic comorbidity, cardiac comorbidity, post-surgical anemia, ADP-receptor inhibitors, acetylsalicylic acid, anticoagulants, and operation type as risk factors for postoperative transfusion. 60.1% of the transfused patients experienced a serious surgical complication within 30 days of surgery compared with 28.1% of the non-transfused patients (p < 0.001). Among patients receiving a postoperative transfusion, unadjusted long-term mortality was increased with a hazard ratio of 3.8 (95% CI 2.9-5.0), p < 0.01. Transfused patients had significantly higher mortality at 7-, 30-, 90- and long-term, as well as a longer hospital stay but in the multivariate analyses, transfusion was not associated with mortality.

CONCLUSION

Peri- and postoperative transfusion in relation to major emergency abdominal surgery was associated with an increased risk of postoperative complications. The potential benefits and harms of blood transfusion and clinical significance of pre- and postoperative anemia after major emergency abdominal surgery should be further studied in clinical prospective studies.

Left ventricular assist device implantation causes platelet dysfunction and proinflammatory platelet-neutrophil interaction

Blood flow through left ventricular assist devices (LVAD) may induce activation and dysfunction of platelets. Dysfunctional platelets cause coagulation disturbances and form platelet-neutrophil conjugates (PNC), which contribute to inflammatory tissue damage. This prospective observational cohort study investigated patients, who underwent implantation of a LVAD (either HeartMate II (HM II) (n = 7) or HeartMate 3 (HM 3) (n = 6)) and as control patients undergoing coronary artery bypass grafting (CABG) and/or aortic valve replacement (AVR) (n = 10). We performed platelet and leukocyte flow cytometry, analysis of platelet activation markers, and platelet aggregometry. Platelet CD42b expression was reduced at baseline and perioperatively in HM II/3 compared to CABG/AVR patients. After surgery the platelet activation marker β-thromboglobulin and platelet microparticles increased in all groups while platelet aggregation decreased. Platelet aggregation was more significantly impaired in LVAD compared to CABG/AVR patients. PNC were higher in HM II compared to HM 3 patients. We conclude that LVAD implantation is associated with platelet dysfunction and proinflammatory platelet-leukocyte binding. These changes are less pronounced in patients treated with the newer generation LVAD HM 3. Future research should identify device-specific LVAD features, which are associated with the least amount of platelet activation to further improve LVAD therapy.

Cryopreservation of buffy coat derived platelets: Paired in vitro characterization using uncontrolled versus controlled freezing rate protocols

Background

Cryopreserved platelets show a reduced recovery and viability after freezing and thawing including several ultrastructural and phenotypic deteriorations compared with liquid‐stored platelets. It is suggested that using Controlled‐Rate Freezing (CRF) can reduce variability and optimize the functionality profile for cells. The objective of the study is to compare cellular, metabolic, phenotypic and functional effects on platelets after cryopreservation using different freezing rate protocols.

Study Design and Methods

To evaluate the possible effects of different freezing rate protocols a two‐experimental study comparing diverse combinations was tested with a pool and split design. Uncontrolled freezing of platelets in materials with different thermal conductivity (metal vs cardboard) was evaluated in experiment 1. Experiment 2 evaluated uncontrolled vs a controlled‐rate freezing protocol in metal boxes. All variables were assessed pre and post cryopreservation.

Results

Directly after thawing, no major differences in platelet recovery, LDH, ATP, Δψ, CD62P, CD42b, platelet endothelial cell adhesion molecule and sCD40L were seen between units frozen with different thermal conductivity for temperature. In contrast, we observed signs of increased activation after freezing using the CRF protocol, reflected by increased cell surface expression of CD62P, PAC‐1 binding and increased concentration of LDH. Agonist induced expression of a conformational epitope on the GPIIb/IIIa complex and contribution to blood coagulation in an experimental rotational thromboelastometry setup were not statistically different between the groups.

Conclusion

The use of a uncontrolled freezing rate protocol is feasible, creating a platelet product comparable to using a controlled rate freezing equipment during cryopreservation of platelets.

Transfusion medicine: Overtime paradigm changes and emerging paradoxes

This essay aims to discuss some aspects of blood transfusion in the perspective of the changes that occurred over time as well as modifications of the paradigms that transformed the activities and the organization of blood transfusion services. Without specific knowledge, pioneers envisioned precision and personalized medicine, rendering transfusion medicine operational. Transfusion medicine is like The Picture of Dorian Grey: always young despite being old and sometimes appearing old-fashioned. Over the years, the transfusion medicine discipline has evolved, and major progress has been achieved, despite some troublesome periods (for example, the tainted blood scandal, and—at the time being—the offending plasma market and the selling of human parts). Transfusion medicine has at all times implemented the rapidly developing biomedical technologies to secure blood components. The safety of blood components has now reached an exceptional level in economically wealthy countries, especially compared to other health care disciplines. Strengthening of the safety has mandated that blood donors and recipients are unrelated, an issue which has eased preservation and fractionation practices; blood is no longer arm-to-arm transfused and neither is whole blood, the commonest component. However, it is interesting to note that a revival is occurring as whole blood is back on stage for certain specific indications, which is one among the many paradoxes encountered while studying this discipline.

The effects of selective beta-adrenergic blockade on bone marrow dysfunction following severe trauma and chronic stress

INTRODUCTION

Propranolol has been shown to improve erythroid progenitor cell growth and anemia following trauma and this study sought to investigate the mechanisms involved by evaluating the effects of selective beta blockade.

METHODS

Male Sprague-Dawley rats were subjected to lung contusion, hemorrhagic shock and chronic stress (LCHS/CS) ± daily selective beta-1, beta-2, or beta-3 blockade (B1B, B2B, B3B). Bone marrow cellularity and growth of erythroid progenitor colonies, hemoglobin, plasma granulocyte colony-stimulating factor (G-CSF), hematopoietic progenitor cell mobilization, and daily weight were assessed.

RESULTS

Selective beta-2 and beta-3 blockade improved bone marrow cellularity, erythroid progenitor colony growth and hemoglobin levels, while decreasing plasma G-CSF, progenitor cell mobilization and weight loss following LCHS/CS.

CONCLUSIONS

Attenuating the neuroendocrine stress response with the use of selective beta-2 and 3 adrenergic blockade may be an alternative to improve bone marrow erythroid function following trauma.

Early Allograft Dysfunction Following Liver Transplant: Impact of Obesity, Diabetes, and Red Blood Cell Transfusion

PURPOSE

We examined the role of obesity and intraoperative red blood cell (RBC) and platelet transfusion in early allograft dysfunction (EAD) following liver transplantation (LT).

METHODS

This is a retrospective analysis of 239 adult deceased-donor LT recipients over a 10-year period. EAD was defined by Olthoff's criteria. Data collection included donor (D) and recipient (R) age, body mass index (BMI) ≥ 35 kg/m², diabetes mellitus, allograft macrosteatosis, and intraoperative (RBC) and platelet administration. We employed logistic regression to evaluate associations of these factors with EAD. Results are presented as odds ratios (OR) and 95% confidence intervals (CI) with corresponding P values. A P ≤ .05 was considered statistically significant.

RESULTS

EAD occurred in 85 recipients (36%). Macrosteatosis data were available for 199 donors. In the multivariate analyses, BMI-D ≥ 35 kg/m² increased the odds of developing EAD by 156% in the entire cohort (OR 2.56, 95% CI 1.09-6.01) and by 187% in recipients with macrosteatosis data (n = 199, OR 2.87, 95% CI 1.15-7.15). Each unit of RBCs increased the odds for EAD by 8% (OR 1.08, 95% CI 1.02-1.14) and, for the subgroup of 238 recipients with macrosteatosis data, by 9% (OR 1.09, 95% CI 1.02-1.16).

CONCLUSION

We found a significant independent association of donor obesity and intraoperative RBC transfusion with EAD but no such association for platelet administration, MELD score, age, recipient obesity, and diabetes.

Dysregulated pathways and differentially expressed proteins associated with adverse transfusion reactions in different types of platelet components

Platelet components (PCs) are occasionally associated with adverse transfusion reactions (ATRs). ATRs can occur regardless of the type of PC being transfused, whether it is a single-donor apheresis PC (SDA-PC) or a pooled PC (PPCs). The purpose of this study was to investigate the proteins and dysregulated pathways in both of the main types of PCs. The proteomic profiles of platelet pellets from SDA-PCs and PPCs involved in ATRs were analysed using the label-free LC-MS/MS method. Differentially expressed proteins with fold changes >|1.5| in clinical cases versus controls were characterised using bioinformatic tools (RStudio, GeneCodis3, and Ingenuity Pathways Analysis (IPA). The proteins were confirmed by western blotting. The common primary proteins found to be dysregulated in both types of PCs were the mitochondrial carnitine/acylcarnitine carrier protein (SLC25A20), multimerin-1 (MMRN1), and calumenin (CALU), which are associated with the important enrichment of platelet activation, platelet degranulation, and mitochondrial activity. Furthermore, this analysis revealed the involvement of commonly dysregulated canonical pathways, particularly mitochondrial dysfunction, platelet activation, and acute phase response. This proteomic analysis provided an interesting contribution to our understanding of the meticulous physiopathology of PCs associated with ATR. A larger investigation would assist in delineating the most relevant proteins to target within preventive transfusion safety strategies. BIOLOGICAL SIGNIFICANCE: Within platelet transfusion strategies, the two primary types of PCs predominantly processed in Europe, include (i) single donor apheresis PCs (SDA-PCs) from one donor and (ii) pooled PCs (PPCs). The current study used PCs from five buffy coats derived from five whole blood donations that were identical in ABO, RH1 and KEL1 groups. Both PC types were shown to be associated with the onset of an ATR in the transfused patient. Several common platelet proteins were found to be dysregulated in bags associated with ATR occurrences regardless of the type of PCs transfused and of their process. The dysregulated proteins included mitochondrial carnitine/acylcarnitine carrier protein (SLC25A20), which is involved in a fatty acid oxidation disorder; calumenin (CALU); and multimerin-1 (MMRN1), which is chiefly involved in platelet activation and degranulation. Dysregulated platelet protein pathways for ATRs that occurred with SDA-PCs and PPCs could support the dysregulated functions found in association with those three proteins. Those common platelet proteins may become candidates to define biomarkers associated with the onset of an ATR from PC transfusions, including monitoring during the quality steps of PC manufacturing, provided that the results are confirmed in larger cohorts. This study enriches our knowledge of platelet proteomics in PCs under pathological conditions.

The Contribution of Storage Medium and Membranes in the Microwave Dielectric Response of Packed Red Blood Cells Suspension

During cold storage, packed red blood cells (PRBCs) undergo slow detrimental changes that are collectively termed storage lesion. The aging of the cells causes alterations in the composition of the storage-medium in the PRBC unit. In this paper, we present the comparison of the dielectric response of water in the primary (fresh) storage medium (citrate phosphate dextrose adenine solution, CPDA-1) versus the storage medium from three expired units of PRBCs. Dielectric response of the water molecules has been characterized by dielectric spectroscopy technique in the microwave frequency band (0.5–40 GHz). The dominant phenomenon is the significant increase of the dielectric strength and decrease the relaxation time τ for the samples of the stored medium in comparison with the fresh medium CPDA-1. Furthermore, we demonstrated that removing the ghosts from PRBC hemolysate did not cause the alteration of the dielectric spectrum of water. Thus, the contribution associated with water located near the cell membrane can be neglected in microwave dielectric measurements.

Platelet depletion limits the severity but does not prevent the occurrence of experimental transfusion-related acute lung injury

BACKGROUND

Transfusion-related acute lung injury (TRALI) is a severe pulmonary reaction due to blood transfusions. The pathophysiology of this complication is still not widely elucidated by the scientific community, especially regarding the direct role of blood platelets within the cellular mechanism responsible for the development of TRALI.

STUDY DESIGN AND METHODS

In this study, a mouse model was used to induce the development of antibody-mediated acute lung injury through injections of lipopolysaccharide and an anti-major histocompatibility complex Class I antibody. BALB/c mice were pretreated with an anti-GPIbα antibody, which induces platelet depletion, or ML354, a protease receptor 4 pathway inhibitor, 30 minutes before TRALI induction.

RESULTS

Depletion of platelets before TRALI induction appeared to reduce the severity of TRALI without completely inhibiting its development. Also, inhibition of platelet activation by ML354 did not prevent the onset of TRALI. Finally, the stimuli used for TRALI induction also triggered specific platelet activation upon ex vivo stimulation.

CONCLUSIONS

This study suggests that blood platelets are not critically required for TRALI induction, although they are to some extent involved in its pathophysiology.

Prospective Cohort Study to Assess the Effect of Storage Duration, Leuko-Filtration, and Gamma Irradiation on Cell-Free DNA in Red Cell Components

Introduction

Damage to a cell and the loss of integrity of its cell membrane leads to the release of endogenous immunogenic molecules, which together are classified as "damage-associated molecular patterns" (DAMPs). Cell-free DNA (cf-DNA) released from nucleosomes may serve as a proco-agulant cofactor and may be an important mediator of immunomodulatory and proinflammatory effects associated with blood transfusion.

Objectives

To assess the levels of cf-DNA in supernatants of stored red cell components and the effect of leukoreduction and gamma irradiation on the release of cf-DNA during storage.

Methods

This is a prospective cohort study on 99 stored red cell components, randomly divided into three groups - buffy coat (BC)-depleted, leuko-filtered (LP), and irradiated (IR) packed red blood cells. Red cell supernatants were drawn over a period of 21 days at three different time points (day 0, 7, and 21) from the study units. cf-DNA extraction was done and quantified by a bench top fluorometer. Change in cf-DNA content, rate of change (μg/day), and percent change were estimated and compared across different groups.

Results

cf-DNA content increased (p = 0.000) with storage duration in the BC (median = 238.66 μg, interquartile range [IQR] = 168.42 on day 21 vs. median = 9.44 μg, IQR = 5.23 on day 0) and IR groups (p = 0.000) (median = 245.55 μg, IQR = 253.88 on day 21 vs. median = 7.07 μg, IQR = 13.58 on day 0), while there was a decreasing trend (p = 0.032) in the LP group (median = 4.55 μg, IQR = 10.73 on day 21 vs. median = 8.66 μg, IQR = 6.56 on day 0). The median rate of change in cf-DNA content (11.13 μg/day) and percent change in cf-DNA content (median = 4,106.16%) was highest in the IR group.

Conclusions

Stored red cell components contain significant amount of cf-DNA. Release of cf-DNA is further aggravated by irradiation while leukoreduction leads to a decrease in cf-DNA content.

Use of red blood cells in Danish intensive care units: A population-based register study

BACKGROUND

Red blood cell (RBC) transfusion is common in the intensive care unit (ICU). Recent trials have shown that a restrictive transfusion strategy is safe in most patients, and recent guidelines recommend such a strategy in most ICU patients. It is unknown if this has translated into a change in clinical practice.

METHODS

We conducted a population-based register study of RBC transfusions in ICUs in the Danish Capital Region between 1st of January 2011 and 31st of December 2016 by linking data from the regional blood bank and the Danish Intensive Care Database. We used crude data and run- and control-charts to analyse changes in the number of RBC transfusions.

RESULTS

We included 27 835 ICU admissions of which 6936 received 40 889 RBC units. The crude use was 36.2 RBC units per one-hundred patient bed-days in 2011 vs 29.8 in 2016. The run-chart analysis did not confirm a change in the total use of RBC units in all ICUs combined, and we observed no change in the proportion of transfused patients or in the use of RBCs among transfused patients. Sensitivity analyses showed decreased use of RBC units in two general ICUs, and a reduced use of RBC units among medical ICU patients.

CONCLUSIONS

In this population-based register study, we did not with certainty observe changes over time in the use of RBC transfusions in all patients in all ICUs in the Danish Capital Region. A reduction in RBC use may have occurred in some general ICUs and in medical ICU patients.

Effect of red blood cell storage duration on major postoperative complications in cardiac surgery: A randomized trial

BACKGROUND

Although observational studies suggest an association between transfusion of older red blood cell (RBC) units and increased postoperative risk, randomized trials have not supported this. The objective of this randomized trial was to test the effect of RBC storage age on outcomes after cardiac surgery.

METHODS

From July 2007 to May 2016, 3835 adults undergoing coronary artery bypass grafting, cardiac valve procedures, or ascending aorta repair, either alone or in combination, were randomized to transfusion of RBCs stored for ≤14 days (younger units) or for ≥20 days (older units) intraoperatively and throughout the postoperative hospitalization. According to protocol, 2448 patients were excluded because they did not receive RBC transfusions. Among the remaining 1387 modified intent-to-treat patients, 701 were randomized to receive younger RBC units (median age, 11 days) and the remaining 686 to receive older units (median age, 25 days). The primary endpoint was composite morbidity and mortality, analyzed using a generalized estimating equation (GEE) model. The trial was discontinued midway owing to enrollment constraints.

RESULTS

A total of 5470 RBC units were transfused, including 2783 in the younger RBC storage group and 2687 in the older RBC storage group. The GEE average relative-effect odds ratio was 0.77 (95% confidence interval [CI], 0.50-1.19; P = .083) for the composite morbidity and mortality endpoint. In-hospital mortality was lower for the younger RBC storage group (2.1% [n = 15] vs 3.4% [n = 23]), as was occurrence of other adverse events except for atrial fibrillation, although all CIs crossed 1.0.

CONCLUSIONS

This clinical trial, which was stopped at its midpoint owing to enrollment constraints, supports neither the efficacy nor the futility of transfusing either younger or older RBC units. The effects of transfusing RBCs after even more prolonged storage (35-42 days) remains untested.

Cytokines and related molecules, and adverse reactions related to platelet concentrate transfusions

Platelet transfusion is a safe process, but during or after the process the recipient may experience an adverse reaction and occasionally a serious adverse reaction (SAR). Platelet concentrate transfusion may be liable for significant absence of beneficial response. Danger may manifest clinically or biologically; in the latter case, manifestations are frequently an absence of the expected response to the blood component by the recipient. Blood platelets exert roles in inflammation, especially through the immunomodulator complex CD40/CD40L (sCD40L). In this review, we concentrate on the inflammatory potential of platelets and their participation to SARs in transfusion.

Immunological Features in the Process of Blood Platelet-Induced Alloimmunisation, with a Focus on Platelet Component Transfusion

Alloimmunisation to platelet antigens is not uncommon; a large number of females, having had pregnancies, developed antibodies to Human Leukocyte Antigen (HLA) moieties harboured on their foetuses' cells (inherited from the father(s)) that may conflict with further pregnancies and transfused Platelet Components occasionally. This is possible since platelets constitutionally express HLA class I molecules (though in copy numbers that consistently differ among individuals). Platelets also express HPA moieties that are variants of naturally expressed adhesion and aggregation molecules; HPA differences between mothers and foetuses and between donors and recipients explain alloimmune conflicts and consequences. Lastly, platelets express ABO blood group antigens, which are rarely immunising, however transfusion mismatches in ABO groups seem to be related to immunisation in other blood and tissue groups. Transfusion also brings residual leukocytes that may also immunise through their copious copy numbers of HLA class I (rarely class II on activated T lymphocytes, B cells, and dendritic cells). In addition, residual red blood cells in platelet concentrates may induce anti-red blood cell allo-antibodies. This short review aims to present the main mechanisms that are commonly reported in alloimmunisation. It also critically endeavours to examine paths to either dampen alloimmunisation occurrences or to prevent them.

Real Age: Red Blood Cell Aging During Storage

BACKGROUND

During cold storage, some red blood cell (RBC) units age more rapidly than others. Yet, the Food and Drug Administration has set a uniform storage limit of 42 days. Objectives of this review are to present evidence for an RBC storage lesion and suggest that functional measures of stored RBC quality-which we call real age-may be more appropriate than calendar age.

METHODS

During RBC storage, biochemical substances and byproducts accumulate and RBC shape alters. Factors that influence the rate of degradation include donor characteristics, bio-preservation conditions, and vesiculation. Better understanding of markers of RBC quality may lead to standardized, quantifiable, and operationally practical measures to improve donor selection, assess quality of an RBC unit, improve storage conditions, and test efficacy of the transfused product.

RESULTS

The conundrum is that clinical trials of younger versus older RBC units have not aligned with in vitro aging data; that is, the units transfused were not old enough. In vitro changes are considerable beyond 28 to 35 days, and average storage age for older transfused units was 14 to 21 days.

CONCLUSIONS

RBC product real age varies by donor characteristics, storage conditions, and biological changes during storage. Metrics to measure temporal changes in quality of the stored RBC product may be more appropriate than the 42-day expiration date. Randomized trials and observational studies are focused on average effect, but, in the evolving age of precision medicine, we must acknowledge that vulnerable populations and individuals may be harmed by aging blood.

Ultraviolet-Based Pathogen Inactivation Systems: Untangling the Molecular Targets Activated in Platelets

Transfusions of platelets are an important cornerstone of medicine; however, recipients may be subject to risk of adverse events associated with the potential transmission of pathogens, especially bacteria. Pathogen inactivation (PI) technologies based on ultraviolet illumination have been developed in the last decades to mitigate this risk. This review discusses studies of platelet concentrates treated with the current generation of PI technologies to assess their impact on quality, PI capacity, safety, and clinical efficacy. Improved safety seems to come with the cost of reduced platelet functionality, and hence transfusion efficacy. In order to understand these negative impacts in more detail, several molecular analyses have identified signaling pathways linked to platelet function that are altered by PI. Because some of these biochemical alterations are similar to those seen arising in the context of routine platelet storage lesion development occurring during blood bank storage, we lack a complete picture of the contribution of PI treatment to impaired platelet functionality. A model generated using data from currently available publications places the signaling protein kinase p38 as a central player regulating a variety of mechanisms triggered in platelets by PI systems.

Irradiation and prolonged storage of red cells are associated with increased adverse events

BACKGROUND

Red blood cell (RBC) transfusion is associated with the most transfusion-related adverse events (AE). Recent clinical studies showed no significant difference in transfusion-associated mortality between fresh and older RBCs. However, the impact of storage duration as well as irradiation on nonfatal yet much more common complications has not been fully investigated.

MATERIALS/METHODS

In this retrospective study of RBC transfusion-associated AEs, a total of 188,562 units of leucocyte-reduced RBCs were transfused in approximately 5·5 years. After excluding washed, deglycerolized, autologous or directed RBCs and RBCs transfused during a massive transfusion protocol, 149,052 units were analysed. Attributes of RBCs including storage time, collection method, CMV serological status and gamma irradiation, as well as the recipient's gender, were analysed. A total of 358 RBC transfusion AEs were categorized into allergic and non-allergic reactions and analysed.

RESULTS

Univariate and multivariate logistic analyses showed that irradiated RBCs were associated with a significantly increased frequency of non-allergic reactions (OR (95% CI): 1·89 (1·52, 2·35); P < 0·001). There was a significant association between the frequency of non-allergic reactions and the storage time of irradiated RBCs (OR (95% CI): 1·024 (1·001, 1·048); P = 0·042). In contrast, there was no association between the frequency of allergic reactions and the storage time of irradiated RBCs or between the age of non-irradiated RBCs and the frequency of non-allergic reactions.

CONCLUSIONS

Prolonged storage of irradiated RBCs was associated with a significant increase in non-allergic transfusion reactions. Overall, the irradiated RBCs appeared to cause more non-allergic reactions compared with non-irradiated RBCs.

Initiation and Propagation of Vascular Calcification Is Regulated by a Concert of Platelet- and Smooth Muscle Cell-Derived Extracellular Vesicles

The ageing population continues to suffer from its primary killer, cardiovascular disease (CVD). Despite recent advances in interventional medicinal and surgical therapies towards the end of the 20th century, the epidemic of cardiovascular disease has not been halted. Yet, rather than receding globally, the burden of CVD has risen to become a top cause of morbidity and mortality worldwide. Most CVD arises from thrombotic rupture of an atherosclerotic plaque, the pathologic thickening of coronary and carotid artery segments and subsequent distal ischemia in heart or brain. In fact, one-fifth of deaths are directly attributable to thrombotic rupture of a vulnerable plaque. Atherosclerotic lesion formation is caused by a concert of interactions between circulating leukocytes and platelets, interacting with the endothelial barrier, signalling into the arterial wall by the release of cytokines and extracellular vesicles (EVs). Both platelet- and cell-derived EVs represent a novel mechanism of cellular communication, particularly by the transport and transfer of cargo and by reprogramming of the recipient cell. These interactions result in phenotypic switching of vascular smooth muscle cells (VSMCs) causing migration and proliferation, and subsequent secretion of EVs. Loss of VSMCs attracts perivascular Mesenchymal Stem Cells (MSCs) from the adventitia, which are a source of VSMCs and contribute to repair after vascular injury. However, continuous stress stimuli eventually switch phenotype of cells into osteochondrogenic VSMCs facilitating vascular calcification. Although Virchow’s triad is over 100 years old, it is a reality that is accurate today. It can be briefly summarised as changes in the composition of blood (platelet EVs), alterations in the vessel wall (VSMC phenotypic switching, MSC infiltration and EV release) and disruption of blood flow (atherothrombosis). In this paper, we review the latest relevant advances in the identification of extracellular vesicle pathways as well as VSMCs and pericyte/MSC phenotypic switching, underlying vascular calcification.

Transfusion-associated hazards: A revisit of their presentation

As a therapy or a support to other therapies, despite being largely beneficial to patients in general, transfusion it is not devoid of some risks. In a moderate number of cases, patients may manifest adverse reactions, otherwise referred to as transfusion-associated hazards (TAHs). The latest French 2016 haemovigilance report indicates that 93% of TAHs are minor (grade 1), 5.5% are moderate (grade 2) and 1.6% are severe (grade 3), with only five deaths (grade 4) being attributed to transfusion with relative certainty (imputability of level [or grade] 1 to 3). Health-care providers need to be well aware of the benefits and potential risks (to best evaluate and discuss the benefit-risk ratio), how to prevent TAHs, the overall costs and the availability of alternative therapeutic options. In high-income countries, most blood establishments (BEs) and hospital blood banks (HBBs) have developed tools for reporting and analysing at least severe transfusion reactions. With nearly two decades of haemovigilance, transfusion reaction databases should be quite informative, though there are four main caveats that prevent it from being fully efficient: (ai) reporting is mainly declarative and is thus barely exhaustive even in countries where it is mandatory by law; (aii) it is often difficult to differentiate between the different complications related to transfusion, diseases, comorbidities and other types of therapies in patients suffering from debilitating conditions; (aiii) there is a lack of consistency in the definitions used to describe and report some transfusion reactions, their severity and their likelihood of being related to transfusion; and (aiv) it is difficult to assess the imputability of a particular BC given to a patient who has previously received many BCs over a relatively short period of time. When compiling all available information published so far, it appears that TAHs can be analysed using different approaches: (bi) their pathophysiological nature; (bii) their severity; (biii) the onset scheme; (biv) a quality assessment (preventable or non-preventable); (bv) their impact on ongoing therapy. Moreover, TAHs can be reported either in a non-integrative or in an integrative way; in the latter case, presentation may also differ when issued by a blood establishment or a treating ward. At some point, a recapitulative document would be useful to gain a better understanding of TAHs in order to decrease their occurrence and severity and allow decision makers to determine action plans: this is what this review attempts to make. This review attempts to merge the different aspects, with a focus on the hospital side, i.e., how the most frequent TAHs can be avoided or mitigated.

Effects of Normovolemic Hemodilution on Survival of Skin Flaps: An Experimental Study

Background

The aim of this study was to investigate the effects of various ratios of hemodilution on the survival of McFarlane’s skin flaps.

Material/Methods

An experimental study was performed on 42 adult male Wistar rats (weighing 260 to 305 g) allocated to a control group without any volume loss and to 6 study groups with hemodilution ratios of 5%, 10%, 15%, 20%, 25%, and 30%. In all subjects, random-pattern McFarlane’s skin flaps were uniformly elevated and re-sutured to the donor sites. The amount of necrosis was evaluated on the 7^th day postoperatively and compared among the groups.

Results

The amounts of flap necrosis in the groups with 5%, 10%, 15%, and 20% hemodilution ratios were significantly lower than that of the control group (p<0.001). In the 25% and 30% hemodilution groups, although there was less necrosis than in the control group, the differences were not statistically significant. Hematocrit levels, which initially decreased in conjunction with the hemodilution ratios, returned to normal levels on the 7^th day after the operation.

Conclusions

Our results indicated that 20% or less of the total blood volume loss that may be compensated by the normovolemic hemodilution with dextran can improve flap survival.

The Non-Hemostatic Aspects of Transfused Platelets

Platelets transfusion is a safe process, but during or after the process, the recipient may experience an adverse reaction and occasionally a serious adverse reaction (SAR). In this review, we focus on the inflammatory potential of platelet components (PCs) and their involvement in SARs. Recent evidence has highlighted a central role for platelets in the host inflammatory and immune responses. Blood platelets are involved in inflammation and various other aspects of innate immunity through the release of a plethora of immunomodulatory cytokines, chemokines, and associated molecules, collectively termed biological response modifiers that behave like ligands for endothelial and leukocyte receptors and for platelets themselves. The involvement of PCs in SARs—particularly on a critically ill patient’s context—could be related, at least in part, to the inflammatory functions of platelets, acquired during storage lesions. Moreover, we focus on causal link between platelet activation and immune-mediated disorders (transfusion-associated immunomodulation, platelets, polyanions, and bacterial defense and alloimmunization). This is linked to the platelets’ propensity to be activated even in the absence of deliberate stimuli and to the occurrence of time-dependent storage lesions.

Toward the Relevance of Platelet Subpopulations for Transfusion Medicine

Circulating platelets consist of subpopulations with different age, maturation state and size. In this review, we address the association between platelet size and platelet function and summarize the current knowledge on platelet subpopulations including reticulated platelets, procoagulant platelets and platelets exposing signals to mediate their clearance. Thereby, we emphasize the impact of platelet turnover as an important condition for platelet production in vivo. Understanding of the features that characterize platelet subpopulations is very relevant for the methods of platelet concentrate production, which may enrich or deplete particular platelet subpopulations. Moreover, the concept of platelet size being associated with platelet function may be attractive for transfusion medicine as it holds the perspective to separate platelet subpopulations with specific functional capabilities.

Effects of red blood cell storage time on transfused patients in the ICU-protocol for a systematic review

BACKGROUND

Patients in the intensive care unit (ICU) are often anaemic due to blood loss, impaired red blood cell (RBC) production and increased RBC destruction. In some studies, more than half of the patients were treated with RBC transfusion. During storage, the RBC and the storage medium undergo changes, which lead to impaired transportation and delivery of oxygen and may also promote an inflammatory response. Divergent results on the clinical consequences of storage have been reported in both observational studies and randomised trials. Therefore, we aim to gather and review the present evidence to assess the effects of shorter vs. longer storage time of transfused RBCs for ICU patients.

METHODS

We will conduct a systematic review with meta-analyses and trial sequential analyses of randomised clinical trials, and also include results of severe adverse events from large observational studies. Participants will be adult patients admitted to an ICU and treated with shorter vs. longer stored RBC units. We will systematically search the Cochrane Library, MEDLINE, Embase, BIOSIS, CINAHL and Science Citation Index for relevant literature, and we will follow the recommendation by the Cochrane Collaboration and the Preferred Reporting Items for Systemtic Review and Meta-Analysis (PRISMA)-statement. We will assess the risk of bias and random errors, and we will use the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach to evaluate the overall quality of evidence.

CONCLUSION

We need a high-quality systematic review to summarise the clinical consequences of RBC storage time among ICU patients.

High Levels of CXCL8 and Low Levels of CXCL9 and CXCL10 in Women with Maternal RhD Alloimmunization

Maternal RhD alloimmunization is an inflammatory response against protein antigens in fetal red blood cells (RBC). However, not all women become alloimmunized when exposed to RhD⁺ fetal RBC. Thus, this study aimed to evaluate levels of inflammatory chemokines in RhD⁻ pregnant women with erythrocyte alloimmunization. CXCL8, CXCL9, CCL5, and CXCL10 levels were determined from cell culture supernatants by flow cytometry in 46 (30 non-alloimmunized RhD⁻ and 16 previously alloimmunized RhD⁻) pregnant women. CXCL8 levels were significantly higher (P < 0.004), and CXCL9 (P < 0.008) and CXCL10 (P < 0.003) levels were significantly lower in alloimmunized pregnant women. No significant difference in CCL5 levels was detected between the groups. Fetal RHD genotyping was performed in the alloimmunized RhD⁻ group by real-time PCR. Anti-D alloantibody was detected in 10 mothers and anti-D and -C in six mothers. Twelve fetuses were RHD positive and four were RHD negative. Further studies of serum chemokines and placenta tissue could provide a better understanding of the cells involved in the pathogenesis of maternal erythrocyte alloimmunization.

Red blood cell transfusion in surgical cancer patients: Targets, risks, mechanistic understanding and further therapeutic opportunities

Anemia is present in more than half of cancer patients and appears to be an independent prognostic factor of short- and long-term adverse outcomes. It increases in the advanced period of cancer and perioperatively, in patients with solid tumors who undergo surgery. As a result, allogeneic red blood cell (RBC) transfusion is an indispensable treatment in cancer. However, its safety remains controversial, based on several laboratory and clinical data reporting a linkage with increased risk for cancer recurrence, infection and cancer-related mortality. Immunological, inflammatory and thrombotic reactions mediated by the residual leukocytes and platelets, the stored RBCs per se, the biological response modifiers and the plasticizer of the unit may underlie infection and tumor-promoting effects. Although the causality between transfusion and infection has been established, the effects of transfusion on cancer recurrence remain confusing; this is mainly due to the extreme biological heterogeneity that characterizes RBC donations and cancer context. In fact, the functional interplay between donation-associated factors and recipient characteristics, including tumor biology per se, inflammation, infection, coagulation and immune activation state and competence may synergistically and individually define the clinical impact of each transfusion in any given cancer patient. Our understanding of how the potential risk is mediated is important to make RBC transfusion safer and to pave the way for novel, promising and highly personalized strategies for the treatment of anemia in surgical cancer patients.