A randomized control trial to compare mortality in recipients of leucoreduced and non-leucoreduced whole blood transfusion in patients with cancer in Uganda

BACKGROUND

Mortality benefit of transfusion with leucoreduced whole blood has not been demonstrated in the sub-Saharan Africa (SSA). We compared mortality in patients with cancer transfused with leucoreduced and non-leucoreduced whole blood in a SSA setting.

METHODS

An open-label randomized controlled trial was conducted at the Uganda Cancer Institute where participants were randomized in a 1:1 ratio into the leucoreduced and non-leucoreduced whole blood transfusion arms. Leucocyte filtration of whole blood was performed within 72 h of blood collection. Patients aged ≥ 15 years who were prescribed blood transfusion by the primary physicians were eligible for study enrolment. Mortality difference was analyzed using intention-to-treat survival analysis and cox proportional hazard model was used to analyze factors associated with mortality.

RESULTS

There were 137 participants randomized to the leucoreduced and 140 to the non-leucoreduced arms. Baseline characteristics were similar between the two arms. The median number of blood transfusions received was 1 (IQR, 1-3) unit and 2 (IQR, 1-3) units in the leucoreduced and non-leucoreduced arms respectively, p = 0.07. The 30-day mortality rate in the leucoreduced arm was 4.6% (95% CI, 2.1-10) and was 6.2% (95% CI, 3.2-12.1) in the non-leucoreduced arm (p = 0.57), representing an absolute effect size of only 1.6%. Increasing age (HR = 0.92, 95% CI, 0.86-0.98, p = 0.02) and Eastern Co-operative Oncology Group (ECOG) performance score of 1 (HR = 0.03, 95% CI, 0.00-0.31, p < 0.01) were associated with reduced 30-day mortality.

CONCLUSIONS

The study failed to demonstrate mortality difference between cancer patients transfused with leucoreduced and non-leucoreduced whole blood. Although this study does not support nor refute universal leucoreduction to reduce mortality in patients with cancer in SSA, it demonstrates the feasibility of doing transfusion RCTs in Uganda, where a multi-center trial with an appropriate sample size is needed.

TRIAL REGISTRATION

Pan African Clinical Trial Registry, https://pactr.samrc.ac.za/ (PACTR202302787440132). Registered on 06/02/2023.

A randomized control trial for evaluation of transfusion related immuno-modulation in patients with meningioma

BACKGROUND

Blood transfusion necessity in neurosurgery varies based on surgical type, blood loss, and patient anemia. Leukocytes in red blood cells (RBCs) component release pro-inflammatory cytokines during storage, contributing to transfusion-related immunomodulation (TRIM). Our aim was to examine the impact of the leukocyte content in transfused PRBCs on patients undergoing neurosurgery for meningioma tumours.

STUDY DESIGN AND METHODS

This prospective randomized controlled trial conducted from 2018 to 2020 by dividing patients randomly into non-leukoreduced (NLR) (n = 65) and leuko-reduced (LR) (n = 65) groups based on PRBCs received during surgery and hospital stay. Hospital and ICU stays, mechanical ventilation duration, and postoperative bacterial infections were observed. Hematological parameters and cytokine levels (IL-10, INF-gamma, and FAS-L) were assessed at pre-transfusion, 24 h, and 7 days post-transfusion. Data analysis included Mann-Whitney U test, Friedman test, Fisher's chi-square test, with statistical significance at p < 0.05.

RESULTS

In our study, ICU and hospital stay duration showed no significant difference (p = 0.06) between groups. However, NLR group had longer mean mechanical ventilation (18 ± 40.1 h) than the LR group (12.8 ± 8.6 h). Both groups showed statistically significant increase in Fas-L level on days 1 and 7 (p < 0.05). The IL-10 levels rose 43% in the NLR group, while and decreased by 7% the LR group on day 1. On day 7, IL-10 increased by 75% in NLR and decreased by 40% in LR, with no significance (p > 0.05).

CONCLUSION

In conclusion, leukoreduction appeared to offer some immune response protection in term of reducing mechanical ventilation timings and cytokine level changes.

Red blood cell transfusion-related dynamics of extracellular vesicles in intensive care patients: a prospective subanalysis

Extracellular vesicles (EVs) accumulate during packed red blood cell (PRBC) storage. To date, the involvement of EVs in transfusion-related immunomodulation (TRIM) has not been prospectively evaluated in intensive care unit (ICU) patients. This was a prospective subanalysis of a recent observational feasibility study in postoperative ICU patients after: (1) open aortic surgery (Aorta), (2) bilateral lung transplantation (LuTx), and (3) other types of surgery (Comparison). Patient plasma was collected three times each before and after leukoreduced PRBC transfusion at 30-min intervals. The total number of EVs and EVs derived from erythrocytes (EryEVs), total platelets (total PEVs), activated platelets, granulocytes (GEVs), monocytes, and myeloid cells in PRBC samples and patient plasma were analyzed by flow cytometry. Statistical analysis was performed by Spearman's correlation test, linear mixed models and pairwise comparisons by Wilcoxon matched-pairs test. Twenty-three patients (Aorta n = 5, LuTx n = 9, Comparison n = 9) were included in the final analysis. All EV subgroups analyzed were detectable in all PRBCs samples (n = 23), but concentrations did not correlate with storage time. Moreover, all EVs analyzed were detectable in all plasma samples (n = 138), and EV counts were consistent before transfusion. Concentrations of total EVs, EryEVs, total PEVs, and GEVs increased after transfusion compared with baseline in the entire cohort but not in specific study groups. Furthermore, the change in plasma EV counts (total EVs and EryEVs) after transfusion correlated with PRBC storage time in the entire cohort. Extracellular vesicles were detectable in all PRBC and plasma samples. Individual EV subtypes increased after transfusion in the entire cohort, and in part correlated with storage duration. Future clinical studies to investigate the role of EVs in TRIM are warranted and should anticipate a larger sample size.Trial registration: Clinicaltrials.gov: NCT03782623.

Erythrocyte-derived extracellular vesicles aggravate inflammation by promoting the proinflammatory macrophage phenotype through TLR4-MyD88-NF-κB-MAPK pathway

Transfusion of stored erythrocytes is associated with the increased risk of morbidity and mortality in critical infections, but the mechanism is incompletely understood. Previous studies have suggested that RBC-derived extracellular vesicles (EVs) may be potential risk factors for the occurrence of transfusion-related immunomodulation. The purpose of our study was to evaluate the effects of RBC-derived EVs under inflammatory conditions and explore the underlying mechanisms. In vivo, the activity of EVs was evaluated in cecal ligation and puncture (CLP)-induced sepsis. Our results showed that EVs significantly aggravated the inflammatory response to sepsis in serum and lung tissue by promoting the production of the proinflammatory factors tumor necrosis factor-α (TNF-α）-interleukin-6(IL-6), and interleukin-1β (IL-1β) and reduced the survival rate of septic mice in vivo. Importantly, adoptive transfer of EVs-pretreated bone marrow-derived macrophages (BMDMs) obviously aggravated systemic proinflammatory factors in mice after CLP surgery. In vitro, the proinflammatory properties of EVs were shown to elevate TNF-α, IL-6, and IL-1β levels in lipopolysaccharide (LPS)-stimulated BMDMs. Moreover, EVs promoted LPS-induced macrophage polarization into a proinflammatory phenotype. The underlying mechanism might involve EV-mediated up-regulation of TLR4-MyD88-NF-κB-MAPK activity to favor macrophage cytokine production.

Blood transfusions increase the risk for venous thromboembolism events following total joint arthroplasty

The association between blood transfusions and thromboembolic events (VTE) following total joint arthroplasty (TJA) remains debatable. Using contemporary institutional data, this study aimed to determine whether blood transfusions increase the risk of VTE following primary and revision TJA. This was a single institution, retrospective cohort study. The clinical records of all patients (n = 34,824) undergoing primary and revision TJA between 2009 and 2020 were reviewed. Demographic variables, co-morbidities, type of chemoprophylaxis and intraoperative factors such as use of tranexamic acid were collected. Clinical notes, hospital orders, and discharge summaries were reviewed to determine if a patient received a blood transfusion. Comprehensive queries utilizing keywords for VTE were conducted in clinical notes, physician dictations, and patient-provider phone-call logs. Propensity score matching as well as adjusted mixed models were performed. After adjusting for various confounders, results from regression analysis showed a significant association between allogenic blood transfusions and risk for developing VTE following primary and revision TJA (OR 4.11, 95% CI 2.53-6.69 and OR 2.15, 95% CI 1.12-4.13, respectively). While this strong association remained significant for PE in both primary (p < 0.001) and revision (p < 0.001) matched cohorts, it was no longer statistically significant for DVT (p = 0.802 and p = 0.65, respectively). These findings suggest that the risk of VTE is increased by approximately three-folds when blood transfusions are prescribed. This association was mainly due to higher symptomatic PE events which makes it even more worrisome. Surgeons should be aware of this association, revisit criteria for blood transfusions and use all means available in the perioperative period to optimize the patients and avoid transfusion.

Increased blood transfusion after outpatient autologous transplantation with reduced intensity conditioning for hematological malignancies predicts worse outcomes

Transfusion has a recognized immunomodulatory effect, and its role on the outcomes after an ambulatory autologous hematopoietic stem cell transplantation (auto-HSCT) following reduced intensity conditioning (RIC) has not been documented. A study to assess factors associated with the number of packed red blood cells (PRBCs) and platelet units transfused and their impact on survival rates of auto-HSCT recipients after RIC was conducted between 2013 and 2019. Transfusions were recorded from days 0 to 100. Of the 130 patients studied, seventy (53.9%) required transfusion support. The median number of PRBC transfused was 2 (range 1-20), and for platelets, it was also 2 units (range 1-19). Infused CD34 + cells/kg, pre-transplant CMV status, and relapse/progression were significantly associated with the number of PRBC units transfused and sex, infused CD34 + cells/kg, and pre-transplant CMV status with the number of platelet units transfused. In multivariate analysis, a high/very high Disease Risk Index (P = .001) (P = .001) and transfusion of ≥ 5 total blood products (P = .001) (P = .010) were associated with decreased disease-free and overall survival. Two-year cumulative incidence of relapse was 50% for transfused patients vs. 34% for those not transfused (P = .009). These data suggest that the transfusion burden and its interplay with other patient and transplant-related factors could be associated with inferior auto-HSCT outcomes.

Convalescent Plasma Therapy for Management of COVID-19: Perspectives and Deployment in the Current Global Pandemic

The world is striving against the severe crisis of the COVID-19 pandemic. Healthcare professionals are struggling to treat their patients based on nonspecific therapies. Amidst this uncertainty, convalescent plasma therapy (CPT) has appeared to be an interim adjuvant therapy for severely ill patients of COVID-19 until long-term clinical trial treatment options are available. Considering the transfusion-related hazards, especially lung injuries and microbial transmission, where sensitivity is not ensured, rigorous trials should be conducted to determine this therapy's efficacy. Moreover, the ratio of recovered cases to plasma donors is not satisfying, which questioning this therapy's availability and accessibility. Although some countries are making the treatment free, the attributable cost mandates a justification for its suitability and sustainability. Our article aimed to review the published facts and findings of CPT's effectiveness in lowering the mortality rate of COVID-19. This pandemic showed that healthcare systems worldwide need core reform. A unified global collaboration must align and coordinate to face the current pandemic and enhance world readiness for future outbreaks based on health equity and equality.

Coronary artery bypass grafting is associated with immunoparalysis of monocytes and dendritic cells

Coronary artery bypass grafting (CABG) triggers a systemic inflammatory response that may contribute to adverse outcomes. Dendritic cells (DC) and monocytes are immunoregulatory cells potentially affected by CABG, contributing to an altered immune state. This study investigated changes in DC and monocyte responses in CABG patients at 5 time-points: admission, peri-operative, ICU, day 3 and day 5. Whole blood from 49 CABG patients was used in an ex vivo whole blood culture model to prospectively assess DC and monocyte responses. Lipopolysaccharide (LPS) was added in parallel to model responses to an infectious complication. Co-stimulatory and adhesion molecule expression and intracellular mediator production was measured by flow cytometry. CABG modulated monocyte and DC responses. In addition, DC and monocytes were immunoparalysed, evidenced by failure of co-stimulatory and adhesion molecules (eg HLA-DR), and intracellular mediators (eg IL-6) to respond to LPS stimulation. DC and monocyte modulation was associated with prolonged ICU length of stay and post-operative atrial fibrillation. DC and monocyte cytokine production did not recover by day 5 post-surgery. This study provides evidence that CABG modulates DC and monocyte responses. Using an ex vivo model to assess immune competency of CABG patients may help identify biomarkers to predict adverse outcomes.

Association Between Transfusion of RBCs and Subsequent Development of Delirium in Critically Ill Children

OBJECTIVES

To determine the temporal relationship between the transfusion of RBCs and the subsequent development of delirium in a cohort of critically ill children.

DESIGN

Nested retrospective cohort study within prospective cohort study.

SETTING

Urban academic tertiary care PICU.

PATIENTS

All consecutive admissions from September 2014 through August 2015.

INTERVENTIONS

Children were screened twice daily for delirium during their PICU admission.

MEASUREMENTS AND MAIN RESULTS

Among 1,547 independent admissions screened for delirium, 166 (10.7%) were transfused RBCs. Children who were transfused RBCs were more than twice as likely to be delirious during their admission compared with children who were never transfused, after controlling for known predictors of delirium development (adjusted odds ratio, 2.16; 95% CI, 1.38-3.37; p = 0.001). Among transfused children, a temporal relationship was observed between receipt of RBCs and the subsequent development of delirium. For each additional 10 mL/kg of RBCs transfused, the recipients were 90% more likely to develop delirium or coma in the 72 hours following the transfusion, after controlling for confounders (adjusted odds ratio, 1.90; 95% CI, 1.14-3.17; p = 0.01). Anemia (represented by nadir hemoglobin prior to transfusion) was not associated with delirium development.

CONCLUSIONS

In this cohort of critically ill children, there is an independent association between the receipt of an RBC transfusion and the subsequent development of delirium. Further prospective studies are warranted to replicate this finding and investigate possible pathophysiologic mechanisms for this association.

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.

Short-term outcome of cardiac surgery under cardiopulmonary bypass in patients who refuse transfusion: a controlled study

BACKGROUND

Although bloodless cardiac surgery has been successfully performed for many years, studies with controls permitting transfusion are few and their results inconclusive. This study compares the outcome of cardiac surgery on Jehovah's Witnesses (JW) refusing transfusion, with that of controls permitting transfusion if required.

METHODS

Data from 172 operations in 162 JW were compared with 172 matched controls. Risk factors, preoperative, operative, 48 hour postoperative variables, outcome data and transfusions were recorded.

RESULTS

Preoperative and operative variables were similar in both groups except for more previous cardiac operations, and more frequent use of cell saver and aprotinin in JW, who bled less and had higher hemoglobin concentrations at all periods. Thirty-day mortality was higher in JW (9.9% vs. 3.5%; P=0.03) (Risk difference 6.4%; CI95%: 2.7-10.1). Nevertheless operative mortality was similar in both groups (9.9% vs. 7.6%; P=0.44). Mortality in low-risk subjects was higher in JW (8.9% vs. 1.0%; P=0.02) (Risk difference 7.9%; CI95%: 2.7-13.2). Moreover, death associated with hemorrhage and anemia tended to be more frequent in JW. Mortality of transfused controls (14.1%) and their matched JW (13.0%) was similar. In contrast, mortality of non-transfused controls was zero versus 6.3% in their matched JW (P=0.059).

CONCLUSIONS

Low-risk JW had significantly higher mortality than controls. Bleeding related deaths tended to be more frequent in JW. Blood-sparing maneuvers should be intensively implemented in both JW and patients permitting transfusion in order to reduce bleeding and the need for transfusion with its harmful effects.

Mechanisms of red blood cell transfusion-related immunomodulation

Red blood cell (RBC) transfusion is common in critically ill, postsurgical, and posttrauma patients in whom both systemic inflammation and immune suppression are associated with adverse outcomes. RBC products contain a multitude of immunomodulatory mediators that interact with and alter immune cell function. These interactions can lead to both proinflammatory and immunosuppressive effects. Defining clinical outcomes related to immunomodulatory effects of RBCs in transfused patients remains a challenge, likely due to complex interactions between individual blood product characteristics and patient-specific risk factors. Unpacking these complexities requires an in-depth understanding of the mechanisms of immunomodulatory effects of RBC products. In this review, we outline and classify potential mediators of RBC transfusion-related immunomodulation and provide suggestions for future research directions.

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.

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.

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.

Soluble Mediators in Platelet Concentrates Modulate Dendritic Cell Inflammatory Responses in an Experimental Model of Transfusion

The transfusion of platelet concentrates (PCs) is widely used to treat thrombocytopenia and severe trauma. Ex vivo storage of PCs is associated with a storage lesion characterized by partial platelet activation and the release of soluble mediators, such as soluble CD40 ligand (sCD40L), RANTES, and interleukin (IL)-8. An in vitro whole blood culture transfusion model was employed to assess whether mediators present in PC supernatants (PC-SNs) modulated dendritic cell (DC)-specific inflammatory responses (intracellular staining) and the overall inflammatory response (cytometric bead array). Lipopolysaccharide (LPS) was included in parallel cultures to model the impact of PC-SNs on cell responses following toll-like receptor-mediated pathogen recognition. The impact of both the PC dose (10%, 25%) and ex vivo storage period was investigated [day 2 (D2), day 5 (D5), day 7 (D7)]. PC-SNs alone had minimal impact on DC-specific inflammatory responses and the overall inflammatory response. However, in the presence of LPS, exposure to PC-SNs resulted in a significant dose-associated suppression of the production of DC IL-12, IL-6, IL-1α, tumor necrosis factor-α (TNF-α), and macrophage inflammatory protein (MIP)-1β and storage-associated suppression of the production of DC IL-10, TNF-α, and IL-8. For the overall inflammatory response, IL-6, TNF-α, MIP-1α, MIP-1β, and inflammatory protein (IP)-10 were significantly suppressed and IL-8, IL-10, and IL-1β significantly increased following exposure to PC-SNs in the presence of LPS. These data suggest that soluble mediators present in PCs significantly suppress DC function and modulate the overall inflammatory response, particularly in the presence of an infectious stimulus. Given the central role of DCs in the initiation and regulation of the immune response, these results suggest that modulation of the DC inflammatory profile is a probable mechanism contributing to transfusion-related complications.

Blood transfusion practices in cancer surgery

Cancer patients are commonly transfused with blood products immediately before, during or after major surgery. Blood loss and haemodilution are the most common causes of red blood cells (RBCs) administration and coagulopathies are the indications for the infusion of fresh-frozen plasma (FFP), cryoprecipitates and platelets. Transfusion-related immune modulation is a complication associated with the administration of blood products. A decreased immune surveillance as a consequence of blood transfusions has been linked to cancer recurrence and progression. Moreover, soluble factors present in packed RBCs, platelets and FFP can directly stimulate tumour growth and spread. Two meta-analyses suggest that the administration of blood products is associated with shorter recurrence-free survival and overall survival after colorectal cancer surgery. More studies are needed to show such association in different cancer patient populations.

Effects of the Sangvia blood collection system on patients undergoing elective hip surgery

We have conducted a randomized controlled study where 164 patients were randomized to receive autologous salvaged blood collected by Sangvia™ Blood Salvage System or allogeneic red cell concentrates if transfusion was indicated by clinical judgement. The study was powered to detect if transfusion of autologous blood reduced the occurrence of postoperative infections. We found no statistical significant difference in postoperative infection rate between the groups, but this may be due to the fact that postoperative infections were diagnosed in only five patients. Increased C-reactive protein concentrations slightly above level of significance indicate that autologous blood transfusions stimulate the patient's immune system. However, there was no indication of increased transfusion reaction rate, including febrile reactions, in the autologous group. Transfusion of autologous blood did not reduce the use of allogeneic red cell concentrates. The mean use of allogeneic red cell concentrates was 0.93 units (both groups combined), indicating that the transfusion policy may have been too liberal. There was a highly significant inverse correlation between pre-operative haemoglobin concentration and transfusion of allogeneic blood. In a patient population with a low frequency of postoperative infection, a larger study is needed to clarify if autologous salvaged blood protects against postoperative infections.

The impact of two different transfusion strategies on patient immune response during major abdominal surgery: a preliminary report

Blood transfusion is associated with well-known risks. We investigated the difference between a restrictive versus a liberal transfusion strategy on the immune response, as expressed by the production of inflammatory mediators, in patients subjected to major abdominal surgery procedures. Fifty-eight patients undergoing major abdominal surgery were randomized preoperatively to either a restrictive transfusion protocol or a liberal transfusion protocol (with transfusion if hemoglobin dropped below 7.7 g dL(-1) or 9.9 g dL(-1), respectively). In a subgroup of 20 patients randomly selected from the original allocation groups, blood was sampled for measurement of IL-6, IL-10, and TNFα. Postoperative levels of IL-10 were higher in the liberal transfusion group on the first postoperative day (49.82 ± 29.07 vs. 15.83 ± 13.22 pg mL(-1), P < 0.05). Peak postoperative IL-10 levels correlated with the units of blood transfused as well as the mean duration of storage and the storage time of the oldest unit transfused (r(2) = 0.38, P = 0.032, r(2) = 0.52, P = 0.007, and r(2) = 0.68, P<0.001, respectively). IL-10 levels were elevated in patients with a more liberal red blood cell transfusion strategy. The strength of the association between anti-inflammatory IL-10 and transfusion variables indicates that IL-10 may be an important factor in transfusion-associated immunomodulation. This trial is registered under ClinicalTrials.gov Identifier: NCT02020525.

T-cell suppression by red blood cells is dependent on intact cells and is a consequence of blood bank processing

BACKGROUND

Red blood cells (RBCs) suppress T-cell responsiveness through a mechanism requiring cell-cell contact. Questions remain as to whether this effect is an allogeneic response, related to cell death, or dependent on particular components of the RBCs.

STUDY DESIGN AND METHODS

Peripheral T cells were isolated from healthy donors and exposed to stored allogeneic RBCs or autologous RBCs after processing. RBCs were lysed by hypotonic solvent to produce cellular ghosts. Tritiated thymidine proliferation assays were utilized. Cultures were saturated with interleukin (IL)-2 to determine whether impaired IL-2 synthesis played a role.

RESULTS

T-cell proliferation was suppressed by both autologous and allogeneic RBCs. RBC membrane integrity does enhance T-cell suppression. T-cell death is not responsible for the suppressive changes. IL-2 synthesis is suppressed in RBC-exposed T cells but addition of exogenous IL-2 does not rescue proliferative capabilities. Proliferation of T cells was inhibited with RBC exposure but mitigated with the addition of fresh RBCs.

CONCLUSIONS

T-cell suppression is enhanced by intact RBCs but this effect is unrelated solely to alloantigens. Neither apoptosis nor necrosis of T cells contributes to this phenomenon. IL-2 synthesis is suppressed after RBC exposure as a consequence of T-cell inhibition, but is not the primary cause of suppression. Fresh RBCs do not mediate T-cell suppression, indicating that changes in the RBC and development of the storage lesion may occur during initial blood bank processing.

Perioperative cardiovascular system failure in South Asians undergoing cardiopulmonary bypass is associated with prolonged inflammation and increased Toll-like receptor signaling in inflammatory monocytes

BACKGROUND

South Asian ethnicity is an independent risk factor for mortality after coronary artery bypass. We tested the hypothesis that this risk results from a greater inflammatory response to cardiopulmonary bypass (CPB).

METHODS

This was a single-site prospective cohort study. We compared the inflammatory response to CPB in 20 Caucasians and 17 South Asians undergoing isolated coronary artery bypass grafting surgery.

RESULTS

Plasma levels of proinflammatory cytokines (interleukin [IL]-6, IL-8, IL-12, interferon gamma, and tumor necrosis factor) and anti-inflammatory mediators (IL-10 and soluble TNF receptor I) were measured. The Toll-like receptor (TLR) signaling pathway was examined in peripheral blood monocytes by flow cytometry, measuring surface expression of TLR2, TLR4, and coreceptor CD14 and activation of downstream messenger molecules (interleukin-1 receptor-associated kinase 4, nuclear factor kappa from B cells (NF-κB), c-Jun amino-terminal kinase, p38 mitogen-activated protein kinase, and Protein Kinase B). South Asians had persistently higher plasma levels of IL-6 and exhibited increased TLR signaling through the p38 mitogen-activated protein kinase and Protein Kinase B pathways in inflammatory monocytes after CPB. This increased inflammatory response was paralleled clinically by a higher sequential organ failure assessment score (5.1 ± 1.4 versus 1.5 ± 1.6, P = 0.027) and prolonged cardiovascular system failure (23.5% versus 0%) 48 h after CPB.

CONCLUSIONS

South Asians develop an exacerbated systemic inflammatory response after CPB, which may contribute to the higher morbidity and mortality associated with coronary artery bypass in this population. These patients may benefit from targeted anti-inflammatory therapies designed to mitigate the adverse consequences resulting from this response.

Immunologic profiles of red blood cells using in vitro models of transfusion

BACKGROUND

Transfusion of packed red blood cells (RBCs) produces a myriad of immunologic derangements, from suppressive to stimulatory. Proliferation of human T cells is suppressed in vitro after exposure to processed red blood cells (PRBCs). We hypothesized that this effect would be mitigated by using fresh RBCs. We also hypothesized that this suppressive effect was a generalized effect on lymphocyte proliferation and would be observed in both CD4+ and CD8+ T-cell subpopulations as well as B cells.

MATERIALS AND METHODS

We isolated human T cells from donor peripheral blood mononuclear cells and exposed them to either blood bank PRBCs or fresh RBCs from volunteer donors and stimulated them with anti-CD3/anti-CD28. Human B cells were stimulated with lipopolysaccharide and exposed to PRBCs or fresh RBCs. We measured proliferation of B cells by thymidine incorporation assays. We also treated RBCs with citrate-phosphate-dextrose (CPD) at different time points before culture them with stimulated T cells to determine the role of this common RBC storage solution in lymphocyte proliferation.

RESULTS

In vitro proliferation of CD4+ and CD8+ T cells was suppressed by blood bank RBCs. This suppression is eliminated when fresh RBCs were used. The B cells showed inhibition of proliferation when exposed to similar conditions, which appeared to be consistent over serial dilutions. Fresh RBCs exposed to CPD did not appear suppressive in the first 6 h after exposure.

CONCLUSIONS

T-cell and B-cell proliferation inhibition by blood banked RBCs suggests a generalized effect of RBCs on cellular proliferation. The lack of suppression by fresh RBCs further suggests that something involved in blood banking alters RBC properties such that they attain a suppressive phenotype. One such blood banking component, CPD, does not appear to affect this suppressive phenotype within the first 6 h.

Ulinastatin, a protease inhibitor, may inhibit allogeneic blood transfusion-associated pro-inflammatory cytokines and systemic inflammatory response syndrome and improve postoperative recovery

BACKGROUND

The aim of this study was to investigate the effects of ulinastatin, a protease inhibitor, and blood transfusion on perioperative surgical complications, changes of systemic inflammatory response syndrome (SIRS) scores, and levels of interleukin-6 (IL-6), interleukin-8 (IL-8) and tumour necrosis factor-α (TNF-α) in patients undergoing liver resection.

MATERIALS AND METHODS

Patients aged 18-65 years were enrolled and divided into four groups (12 patients in each group): a control group, a group given ulinastatin (UTI group), a group given blood transfusion (BT group), and a group given both blood transfusion and ulinastatin (BT+UTI group). Patients were randomised to receive ulinastatin or not, whereas blood transfusion was administered based on a transfusion trigger. Ulinastatin was given at a dose of 100,000 units/10 kg, infused 15 min before allogeneic blood transfusion or after completion of the liver resection. The patients were followed up for 3 days to record surgical complications, SIRS scores and levels of IL-6, IL-8 and TNF-α.

RESULTS

Forty-four patients were included in the data analysis. The SIRS rate (SIRS scores≥2) was significantly higher in the BT groups than in the control group at 6 hours and on day 3 after surgery and was significantly lower in the BT+UTI group than in the BT group on day 3 after surgery. Allogeneic blood transfusion significantly increased and ulinastatin significantly decreased postoperative levels of IL-6, IL-8, and TNF-α. The length of stay in hospital was significantly longer in the BT groups than in the control group but was not significantly different between the BT+UTI and BT groups.

CONCLUSION

A single dose of ulinastatin before allogeneic blood transfusion may lower the rate of postoperative SIRS and levels of IL-6, IL-8 and TNF-α associated with allogeneic blood transfusion and improve patients' postoperative recovery.

Pulmonary complications of transfused blood components

Three transfusion complications are responsible for the majority of the morbidity and mortality in hospitalized patients. This article discusses the respiratory complications associated with these pathophysiologic processes, including definitions, diagnosis, mechanism, incidence, risk factors, clinical management, and strategies for prevention. It also explores how different patient populations and different blood components differentially affect the risk of these deadly transfusion complications. Lastly, the article discusses how health care providers can risk stratify individual patients or patient populations to determine whether a given transfusion is more likely to benefit or harm the patient based on the transfusion indication, risk, and expected result.

Impact of blood product transfusion on short and long-term survival after cardiac surgery: more evidence

BACKGROUND

Despite the proven benefits in hemorrhagic shock, blood transfusions have been linked to increased morbidity and mortality. The short-term adverse effects of blood transfusion in cardiac surgical patients are well documented but there are very few studies that adequately assess the long-term survival. This study was undertaken to evaluate the effects of transfusion on both short-term and long-term survival after cardiac surgery.

METHODS

Data from 5,342 patients who underwent a cardiac surgical procedure from January 2002 to December 2005 at our institution were reviewed. The effect of transfusion of packed red blood cells (PRBC) and other blood products was tested in a 2-level approach of transfusion (any) versus no transfusion, and also a 4-level approach of transfusion (PRBC, other blood products, and both blood and blood products) versus no transfusion. Long-term survival data of these patients were obtained. Cox proportional hazard models, Kaplan-Meier survival plots, and hazard functions were used to compare the groups.

RESULTS

A total of 3,013 of the 5,342 study patients (56.4%) received transfusion during or within 72 hours of their cardiac surgery. Median time to death was significantly lower for patients who received transfusions; 1.15 years for PRC and 0.83 years for any transfusion, compared with 4.68 years in the non-transfused group. The overall 30-day mortality was 1.7%, but in patients who received transfusions (3.6%) was significantly higher than the non-transfused group (0.3%, p<0.001). The 1-year mortality (overall 3.9%) in the transfused group (7.3%, p<0.001) was also significantly higher than that in the non-transfused group (1.3%). The 5-year mortality rate in the transfused group was more than double that in the non-transfused group (16% vs 7%). After correction for comorbidities and other factors, transfusion was still associated with a 66% increase in mortality.

CONCLUSIONS

This study suggests that blood or blood product transfusion during or after cardiac surgery is associated with increased short-term and long-term mortality. It reinforces the need for prospective randomized controlled studies for evaluation of restrictive transfusion triggers and objective clinical indicators for transfusion in the cardiac surgical patient population.

Accumulation of pro-cancer cytokines in the plasma fraction of stored packed red cells

INTRODUCTION

Perioperative blood transfusion has been linked to decreased survival in pancreatic cancer; however, the exact causal mechanism has not been elucidated. Allogeneic transfusions are known to expose patients to foreign cells and lipid mediators. We hypothesize that stored packed red cells (pRBCs) contain pro-cancer cytokines that augment tumor progression. We analyzed the plasma fraction of stored pRBCs for pro-cancer cytokines and evaluated the affect of both storage time and leukocyte reduction on these mediators.

METHODS

Chemiarray™ analysis for pro-cancer cytokines was performed on the acellular plasma fraction of stored leukocyte-reduced (LR) and non-leukocyte-reduced (NLR) pRBCs at day 1 (D.1-fresh) and day 42 (D.42-outdate) of storage. Elevated expression of monocyte chemotactic protein-1 (MCP-1), regulated on activation, normal T cell expressed and secreted (RANTES), angiogenin, tumor necrosis factor-alpha (TNF-α), epidermal growth factor (EGF), and platelet-derived growth factor (PDGF) was found. Specific enzyme-linked immunosorbent assay was performed for each of these factors in LR and NLR blood at D.1, day 28, and D.42. Data were analyzed by ANOVA. A p value ≤ 0.05 was considered significant; N ≥ 4 per group. Migration assays were performed using inhibitors of EGF (gefitinib) and PDGF (imatinib) on murine pancreatic adenocarcinoma cells (Pan02) exposed to D.1 and D.42 LR and NLR plasma. Proliferation assays were performed on Pan02 cells to test the inhibition of PDGF.

RESULTS

MCP-1 levels increased with storage time in LR blood, 86.3 ± 6.3 pg/ml at D.1 vs. 121.2 ± 6.1 pg/ml at D.42 (p = 0.007), and NLR blood, 78.2 ± 7.3 pg/ml at D.1 vs. 647.8 ± 220.7 pg/ml at D.42 (p = 0.02). RANTES levels are lower in LR compared to NLR stored blood, 3.0 ± 1.9 vs. 15.8 ± 0.7 pg/ml at D.42 (p < 0.001), but similar in D.1 blood, 13.8 ± 1.8 pg/ml in LR vs. 12.0 ± 1.6 pg/ml in NLR. Angiogenin levels were different between LR and NLR blood, 0 pg/ml (undetectable) vs. 44.2 ± 3.7 pg/ml (p < 0.001). Storage time did not affect concentration. TNF-α levels were not different between LR and NLR blood, and there was no storage time effect on concentration. EGF and PDGF levels increased with storage time in NLR blood only, 216.4 ± 3.8 pg/ml at D.1 vs. 1,436.4 ± 238.6 pg/ml at D.42 for EGF (p = 0.001), and 61.6 ± 6.0 pg/ml at D.1 vs. 76.5 ± 1.7 pg/ml at D.42 (p = 0.003) for PDGF. Inhibition of EGF reduced migration in Pan02 cells treated with D.42 NLR blood, 245.9 ± 11.2 vs. 164.6 ± 10.6 cells/hpf (p < 0.001). Inhibition of PDGF had no effect on Pan02 migration and reduced cell proliferation in cells treated with D.42 NLR, 181.1 ± 1.5% over control vs. 157.5 ± 2.1% (p < 0.001).

CONCLUSION

Pro-cancer cytokines that can augment tumor progression were identified in pRBCs. Some of these factors are present in fresh blood. The soluble factors identified herein may represent possible therapeutic targets to offset negative effects of transfusion. These data stress the need for efforts in cancer patients to reduce transfusion requirements if needed.

The effect of RBC transfusions on cytokine gene expression after cardiac surgery in patients developing post-operative multiple organ failure

AIM

To determine the effect of red blood cell (RBC) transfusions during cardiac surgery on cytokine gene expression (GE) in relation to multiple organ failure (MOF) development after systemic inflammatory response syndrome (SIRS).

BACKGROUND

RBC transfusion in cardiac surgery patients is dose-dependently associated with post-operative MOF, possibly acting as a second hit after cardiopulmonary bypass.

METHODS

For this observational study, 29 patients divided into four groups of cardiac surgery patients were selected from a randomised controlled trial (RCT). Group 1: no-RBC, no-MOF (N = 8); group 2: MOF, no-RBC (N = 7); group 3: RBC, no-MOF (N = 6); group 4: RBC and MOF (N = 8). Selection was based on age, gender, number of (leukocyte-depleted) RBC transfusions, type and duration of surgery. A 114 cytokine GE array was applied to blood samples withdrawn before and 24 h after surgery. Expression of selected genes was confirmed with reverse transcriptase real time-polymerase chain reaction (RT-PCR).

RESULTS

Nineteen of the 39 detectable genes showed a significant change in GE after surgery. Confirmed by RT-PCR, transfused MOF patients exhibit significantly less downregulation of CD40 ligand than control patients. Patients who would develop MOF show significantly larger increases in GE of transforming growth factor-α (TGF-α), tumour necrosis factor (TNF)-superfamily members 10 and 13B (TNFsf10/13B).

CONCLUSIONS

When tested at 24 h after surgery, cytokine GE in peripheral blood leucocytes showed no significant differences between those transfused and those not transfused. Some alterations were seen in those developing MOF compared to those who did not, but the findings offer no role of leukocyte depleted (LD) RBC transfusion in the development of MOF.

The optimal hematocrit

Nearly 15 million units of packed red blood cells and whole blood are transfused annually in the United States alone. Until recently, the major risks from blood transfusion were thought to be transmission of viral infections, and overall, blood transfusion was believed by most providers to be safe. A safe hemoglobin threshold above which red cell transfusion is clearly unnecessary has not been established. This article addresses the numerous problems that surround the use and consequences of blood transfusion, such as hemoglobin and hematocrit levels, oxygenation, storage time, immunomodulation, infection, and anemia. The relevant literature is comprehensively reviewed.

Blood still kills: six strategies to further reduce allogeneic blood transfusion-related mortality

After reviewing the relative frequency of the causes of allogeneic blood transfusion-related mortality in the United States today, we present 6 possible strategies for further reducing such transfusion-related mortality. These are (1) avoidance of unnecessary transfusions through the use of evidence-based transfusion guidelines, to reduce potentially fatal (infectious as well as noninfectious) transfusion complications; (2) reduction in the risk of transfusion-related acute lung injury in recipients of platelet transfusions through the use of single-donor platelets collected from male donors, or female donors without a history of pregnancy or who have been shown not to have white blood cell (WBC) antibodies; (3) prevention of hemolytic transfusion reactions through the augmentation of patient identification procedures by the addition of information technologies, as well as through the prevention of additional red blood cell alloantibody formation in patients who are likely to need multiple transfusions in the future; (4) avoidance of pooled blood products (such as pooled whole blood-derived platelets) to reduce the risk of transmission of emerging transfusion-transmitted infections (TTIs) and the residual risk from known TTIs (especially transfusion-associated sepsis [TAS]); (5) WBC reduction of cellular blood components administered in cardiac surgery to prevent the poorly understood increased mortality seen in cardiac surgery patients in association with the receipt of non-WBC-reduced (compared with WBC-reduced) transfusion; and (6) pathogen reduction of platelet and plasma components to prevent the transfusion transmission of most emerging, potentially fatal TTIs and the residual risk of known TTIs (especially TAS).

Red blood cell transfusion in the treatment and management of anaemia: the search for the elusive transfusion trigger

Therapeutic red blood cell (RBC) transfusion is widely utilized in the management of anaemia. Critically ill intensive care unit (ICU) patients in particular, as well as medical and haematology-oncology patients, are among the largest groups of users of RBC products. While anaemia is common in these patients, its treatment and management, including appropriate thresholds for RBC transfusion, remain controversial. We review here the function of RBCs in oxygen transport and physiology, with a view to their role in supporting and maintaining systemic tissue oxygenation. Adaptive and physiological compensatory mechanisms in the setting of anaemia are discussed, along with the limits of compensation. Finally, data from clinical studies will be examined in search of evidence for, or against, a clinically relevant transfusion trigger.

Hospital variation in transfusion and infection after cardiac surgery: a cohort study

BACKGROUND

Transfusion practices in hospitalised patients are being re-evaluated, in part due to studies indicating adverse effects in patients receiving large quantities of stored blood. Concomitant with this re-examination have been reports showing variability in the use of specific blood components. This investigation was designed to assess hospital variation in blood use and outcomes in cardiac surgery patients.

METHODS

We evaluated outcomes in 24,789 Medicare beneficiaries in the state of Michigan, USA who received coronary artery bypass graft surgery from 2003 to 2006. Using a cohort design, patients were followed from hospital admission to assess transfusions, in-hospital infection and mortality, as well as hospital readmission and mortality 30 days after discharge. Multilevel mixed-effects logistic regression was used to calculate the intrahospital correlation coefficient (for 40 hospitals) and compare outcomes by transfusion status.

RESULTS

Overall, 30% (95 CI, 20% to 42%) of the variance in transfusion practices was attributable to hospital site. Allogeneic blood use by hospital ranged from 72.5% to 100% in women and 49.7% to 100% in men. Allogeneic, but not autologous, blood transfusion increased the odds of in-hospital infection 2.0-fold (95% CI 1.6 to 2.5), in-hospital mortality 4.7-fold (95% CI 2.4 to 9.2), 30-day readmission 1.4-fold (95% CI 1.2 to 1.6), and 30-day mortality 2.9-fold (95% CI 1.4 to 6.0) in elective surgeries. Allogeneic transfusion was associated with infections of the genitourinary system, respiratory tract, bloodstream, digestive tract and skin, as well as infection with Clostridium difficile. For each 1% increase in hospital transfusion rates, there was a 0.13% increase in predicted infection rates.

CONCLUSION

Allogeneic blood transfusion was associated with an increased risk of infection at multiple sites, suggesting a system-wide immune response. Hospital variation in transfusion practices after coronary artery bypass grafting was considerable, indicating that quality efforts may be able to influence practice and improve outcomes.

Transfusion-related mortality: the ongoing risks of allogeneic blood transfusion and the available strategies for their prevention

As the risks of allogeneic blood transfusion (ABT)-transmitted viruses were reduced to exceedingly low levels in the US, transfusion-related acute lung injury (TRALI), hemolytic transfusion reactions (HTRs), and transfusion-associated sepsis (TAS) emerged as the leading causes of ABT-related deaths. Since 2004, preventive measures for TRALI and TAS have been implemented, but their implementation remains incomplete. Infectious causes of ABT-related deaths currently account for less than 15% of all transfusion-related mortality, but the possibility remains that a new transfusion-transmitted agent causing a fatal infectious disease may emerge in the future. Aside from these established complications of ABT, randomized controlled trials comparing recipients of non-white blood cell (WBC)-reduced versus WBC-reduced blood components in cardiac surgery have documented increased mortality in association with the use of non-WBC-reduced ABT. ABT-related mortality can thus be further reduced by universally applying the policies of avoiding prospective donors alloimmunized to WBC antigens from donating plasma products, adopting strategies to prevent HTRs, WBC-reducing components transfused to patients undergoing cardiac surgery, reducing exposure to allogeneic donors through conservative transfusion guidelines and avoidance of product pooling, and implementing pathogen-reduction technologies to address the residual risk of TAS as well as the potential risk of the next transfusion-transmitted agent to emerge in the foreseeable future.