Improving platelet transfusion safety: biomedical and technical considerations

Development and implementation of restrictive platelet transfusion thresholds in a neonatal intensive care unit

OBJECTIVE

Thrombocytopenia is a common problem affecting preterm neonates. Recent studies show increased morbidity and mortality with liberal platelet transfusion thresholds. We sought to standardize thrombocytopenia management through a transfusion guideline to reduce excessive transfusions.

STUDY DESIGN

We developed and implemented a guideline using PDSA cycles for infants with birth weights <1000 grams. Platelet transfusions were classified as indicated or non-indicated per the guideline. Severe (grade 3 or 4) intraventricular hemorrhage and pulmonary hemorrhage rates were balancing measures.

RESULTS

We analyzed 101 infants pre-guideline and 96 infants post-guideline. The mean monthly non-indicated transfusions significantly decreased from 13.0 to 2.0, respectively (p-value < 0.01). Incidence of severe grade IVH and pulmonary hemorrhage remained stable.

CONCLUSION

Rapid implementation of an evidence-based, restrictive platelet transfusion guideline significantly reduced non-indicated platelet transfusions without a concomitant increase in major bleeding events.

Recent developments in microfluidic passive separation to enable purification of platelets for transfusion

Platelet transfusion is a lifesaving therapy intended to prevent and treat bleeding. However, in addition to platelets, a typical unit also contains a large volume of supernatant that accumulates multiple pro-inflammatory contaminants, including residual leukocytes, microaggregates, microparticles, antibodies, and cytokines. Infusion of this supernatant is responsible for virtually all adverse reactions to platelet transfusions. Conventional methods for removing residual leukocytes (leukoreduction) and reducing the volume of transfused supernatant (volume reduction) struggle to mitigate these risks holistically. Leukoreduction filters can remove leukocytes and microaggregates but fail to reduce supernatant volume, whereas centrifugation can reduce volume, but it is ineffective against larger contaminants and damages platelets. Additionally, platelet purification based on these methods is often too logistically complex, time-consuming, and labor-intensive to implement routinely. Emerging microfluidic technologies offer promising alternatives through passive separation mechanisms that enable cell separation with minimal damage and drastically reduced instrumentation size and facility requirements. This review examines recent innovations in microfluidic cell separation that can be used for leukoreduction and volume reduction of platelets. It begins by defining the performance requirements that any separation method must meet to successfully replace conventional methods currently used to perform these tasks. Standard performance metrics are described, including leukocyte depletion efficiency, degree of volume reduction, processing throughput, and platelet recovery. Finally, the review outlines the primary challenges that must be overcome to enable simple-to-use, disposable microfluidic devices capable of both reducing the platelet unit volume and removing pro-inflammatory contaminants, while preserving most functional platelets for transfusion.

Designing a linear accelerator-based "X irradiation system" for platelet products: an efficient, safe, accessible and cost-effective alternative for conventional X- or gamma irradiators

X-irradiation of blood products is an alternative for gamma-ray to prevent post-transfusion GvHD. However, commercial X-irradiators are not widely available while little is known about their safety and efficacy for platelet products. This study introduces an efficient, accessible and cost-effective "X irradiation system" for platelet concentrates (PCs). By constructing a suitable radiation box (phantom) for a clinically available linear accelerator, an "X irradiation system" was designed specifically for PCs. PCs were divided into three equal bags either exposed to X- and gamma-irradiation or kept unirradiated (control). Irradiation-induced inhibition of T cells proliferation was examined by MTT and cell cycle assays on mononuclear cells (MNCs) obtained from PCs. The inhibitory effect of irradiation on allorecognition ability of MNCs was assessed by mixed lymphocyte reaction where MTT evaluated lymphocyte proliferation responses and flowcytometry examined CD8+T lymphocytes activity. Platelet activation was also examined with P-selectin expression and PAC-1 binding by flowcytometry. X- and gamma-irradiation reduced T cell proliferation while disturbing the cell-cycle with reduced entry of T-cells into the S phase and their G2 arrest. Both types of irradiations also effectively reduced "lymphocyte allorecognition responses" while inactivating CD8+T lymphocytes in platelet products but with no significant effect on platelet activity. This is the first study that showed "X irradiation system" effectively suppresses T cell proliferation and CD8+T lymphocyte activity in platelet products, with no effect to platelet quality and activation markers. This may suggest the LINAC-based "X irradiation system" with a dose of 30Gy as efficient and safe as gamma-irradiation for platelet products.

Postoperative bleeding after dentoalveolar surgery in patients with thrombocytopenia-are prophylactic platelet transfusions necessary?

PURPOSE

Benefits of prophylactic platelet (PLT) transfusion before dentoalveolar surgery are unclear. This study investigated the effect of prophylactic PLT transfusions on the incidence of postoperative bleeding (POB) in patients with thrombocytopenia and a PLT count ≤ 75*109/L.

METHODS

The cohort in this retrospective study comprised 83 patients with thrombocytopenia ≤ 75*109/L who had undergone dentoalveolar surgery. Exclusion criteria were other coagulation deficiencies or medications that would affect hemostasis. In all, 144 teeth had been removed. POB events were extracted and compared between the group that had received prophylactic PLT transfusion before dentoalveolar surgery and the group that had not.

RESULTS

POB events were observed in 5 of 83 patients (6.0%) who had a median PLT count of 35*109/L before any transfusion. The group with no postoperative bleeding (NPOB) had a median PLT count of 34*109/L. Two (4.2%) of the 48 patients who had received prophylactic PLT transfusions before dentoalveolar surgery developed POB. Three (8.6%) of the 35 patients who had not received a transfusion experienced POB. The difference between these two groups was not significant (p = 0.646). When two or more teeth were removed in the same session, a significantly higher incidence of POB was observed (p = 0.042).

CONCLUSIONS

Our data indicate that prophylactic PLT transfusions in thrombocytopenic patients with PLT counts ≤ 75*109/L do not reduce the incidence of POB after dentoalveolar surgery. However, caution is warranted when extracting multiple teeth in the same surgical session since we found this to be significantly associated with an increased risk of POB.

Changes in inflammatory proteins following platelet transfusion in a neonatal population

BACKGROUND

Studies have demonstrated increased morbidity and mortality with platelet transfusions in the neonatal period. Platelets are as important for host immunity and inflammation as for hemostasis. Increased inflammation may explain the dose-associated increase in mortality, bleeding, and lung disease.

OBJECTIVE

This study aims to assess if there are any changes in inflammatory cytokines post-platelet transfusion in babies in NICU.

METHODS

This prospective observational study recruited babies due to receive a non-emergency platelet transfusion. Dried whole blood samples were collected prior to and 2 h post-transfusion. Samples were processed using multiplex immunoassay to enable analysis of tiny blood volumes. Statistical analysis was performed using R.

RESULTS

Seventeen babies underwent 26 platelet transfusions across two centers. Median birthweight was 1545 g (535-3960 g) and median birth gestation was 31 weeks and 1 day (23 + 1 to 40 + 5). Median pre-transfusion platelet count was 19.5 × 109/l. There was a significant increase in levels of CXCL5 (p < 0.001), CD40 (p = 0.001), and TGF-β (p = 0.001) in neonatal blood samples post-platelet transfusion in the study group.

CONCLUSION

The increase in the cytokines CXCL5, CD40 and TGF-β after platelet transfusion in babies in NICU could potentiate existing inflammation, NEC, lung, or white matter injury. This could potentially explain long-term harm from platelet transfusion in babies.

IMPACT

There is a change in levels of immunomodulatory proteins CXCL5, CD40, and TGF-β after platelet transfusion in babies in NICU. Murine neonatal models have demonstrated an increase in cytokine levels after platelet transfusions. This is the first time that this has been demonstrated in human neonates. The increase in proinflammatory cytokines could potentially explain the long-term harm from platelet transfusion in babies, as they could potentiate existing inflammation, NEC, lung injury, or white matter injury.

[Use of Thrombopoetin-Receptor-Agonists (TPO-RA) in patients with liver cirrhosis before invasive procedures]

Advanced chronic liver disease is accompanied with relevant changes in the corpuscular and plasmatic coagulation system. Due to thrombocytopenia that is regularly observed in these patients, platelet transfusions are often performed prior invasive procedures to prevent possible bleeding complications. However, platelet transfusions are associated with clinically significant adverse events and economically relevant health care costs. Thus, avoiding unnecessary platelet transfusions remains pivotal in daily clinical practice. The first step is to carefully check if increasing platelet counts prior to a planned invasive procedure is really necessary. Nowadays, two well-tolerated thrombopoetin-receptor agonists (TPO-RAs), Avatrombopaq and Lusutrombopaq, to treat thrombocytopenia preemptively before an invasive procedure in patients with liver cirrhosis are available. This review provides a guide for clinician when to increase platelet counts prior an invasive procedure in patients with liver cirrhosis and helps to identify situations in which the use of TPO-RA may be reasonable.

Cryo-Shocked Platelet Coupled with ROS-Responsive Nanomedicine for Targeted Treatment of Thromboembolic Disease

Thrombolysis with tissue plasminogen activator (tPA) provides the most common therapy for ischemic stroke onset within the past 4.5 h. However, enhanced neutrophil infiltration and secondary blood-brain barrier injury caused by tPA administration have limited its therapeutic application, and tPA treatment is often accompanied by hemorrhagic transformation. To overcome the limitations of thrombolysis by tPA, maximize the therapeutic efficacy, and improve the safety, herein, we report a cryo-shocked platelet-based cell-hitchhiking drug delivery system, which consists of cryo-shocked platelet (CsPLT) and reactive oxygen species (ROS)-responsive liposomes loaded with thrombolytic tPA and anti-inflammation drug aspirin (ASA). CsPLT and liposomes were facilely conjugated via host-guest interactions. Under the guidance of CsPLT, it selectively accumulated in the thrombus site and quickly released the therapeutic payloads in response to the high ROS. tPA subsequently exhibited localized thrombolytic activity to suppress the expansion of thrombus, while ASA assisted in the inactivation of reactive astrogliosis, microglial/macrophage, and obstruction of neutrophil infiltration. This cryo-shocked platelet-hitchhiking tPA/ASA delivery system not only improves the thrombus-targeting efficiency of the two drugs for highly localized thrombolytic effects and anti-inflammation actions and platelets inactivation but also provides insights to the development of targeted drug delivery systems for thromboembolic disease treatment.

The impact of perioperative red blood cell transfusion on the prognosis of colorectal cancer

Background

There is no consensus on the effect of red blood cell transfusion on colorectal cancer (CRC). This study examined the impact of perioperative red blood cell transfusion on postoperative complications, recurrence, and mortality in patients with CRC.

Methods

In this retrospective cohort study, 219 CRC patients admitted to Chongqing Emergency Medical Center, and Chongqing University Central Hospital from 2008 to 2019 were divided into transfusion (n = 75) and non-transfusion (n = 144) groups. Univariate and multivariate Logistic regression analysis were used to analyze the effects of blood transfusion on the severity of postoperative complications in patients with CRC, and univariate and multivariate Cox regression was performed to analyze the effects of blood transfusion on postoperative death and recurrence.

Results

Twenty-two (29.33%) patients in the transfusion group were intermediate or advanced severity of postoperative complications, 31 (41.33%) patients died in the transfusion group, and 55 (73.33%) patients occurred recurrence of the CRC, with the median follow-up time being 24.57(14.50,36.37) months. Our result showed that perioperative red blood cell transfusion was associated with an increased risk of intermediate or advanced severity of postoperative complications in CRC patients [odds ratio (OR) = 3.368, 95% CI, 1.146–9.901]. And perioperative red blood cell transfusion increased the risk of postoperative death [hazard ratio (HR) = 2.747, 95% CI, 1.048–7.205] and recurrence in patients with CRC (HR = 2.168, 95% CI, 1.192–3.943).

Conclusion

Our finding demonstrated that perioperative red blood cell transfusion was associated with severity of complications, recurrence, and death in CRC patients. However, further studies are still needed to confirm the adverse effects of red blood cell transfusions in CRC patients.

Expanded validation of the effect and quality of a pathogen inactivation system based on riboflavin photochemistry on platelet bacterial contamination

Background

Bacterial contamination still poses serious challenges to blood safety. Platelets have the highest bacterial contamination risk of all blood components.

Methods

Twenty units of manual platelets were prepared from blood donated by our hospital, which were inoculated with Staphylococcus aureus and Escherichia coli suspensions. The riboflavin sodium phosphate solution was added into platelets, adjusted to a final concentration of 160 μmol/L. Platelets added into an illumination bag and placed in the inactivation system for riboflavin photochemistry at various doses. The inactivation effect of bacteria was evaluated on a Columbia blood agar plate by the plate counting method. Meanwhile, the blood routine, blood gas analysis, platelet aggregation test, and thromboelastogram of platelets before and after treatment were detected to evaluate the changes of platelet quality after treatment.

Results

the inactivation effect of S. aureus and E. coli at the inactivation dose (16.9 J/cm²) could reach more than 4 logs. After treatment at 16.9 J/cm², the blood routine results showed that the platelet count was significantly different (P<0.05), and the blood gas analysis showed that the oxygen partial pressure (pO₂) and lactic acid concentration (cLac) were also significantly different (P<0.05). After 16.9 J/cm² treatment, there was a significant difference between Arachidonic acid (AA) and Collagen (Cog) activator groups in the platelet aggregation experiment (P<0.05), but there was no significant difference in the main thrombelastogram (TEG) parameters (R value, K value, angle value, MA value) after treatment (P>0.05).

Conclusions

The inactivation effect of this set of blood component pathogen inactivation system on platelet bacterial contamination could be considered to meet actual clinical needs, with the inactivation treatment having little impact on platelet function.

Platelet Transfusion-Insights from Current Practice to Future Development

Since the late sixties, therapeutic or prophylactic platelet transfusion has been used to relieve hemorrhagic complications of patients with, e.g., thrombocytopenia, platelet dysfunction, and injuries, and is an essential part of the supportive care in high dose chemotherapy. Current and upcoming advances will significantly affect present standards. We focus on specific issues, including the comparison of buffy-coat (BPC) and apheresis platelet concentrates (APC); plasma additive solutions (PAS); further measures for improvement of platelet storage quality; pathogen inactivation; and cold storage of platelets. The objective of this article is to give insights from current practice to future development on platelet transfusion, focusing on these selected issues, which have a potentially major impact on forthcoming guidelines.

Alterations in platelet behavior after major trauma: adaptive or maladaptive?

Platelets are damage sentinels of the intravascular compartment, initiating and coordinating the primary response to tissue injury. Severe trauma and hemorrhage induce profound alterations in platelet behavior. During the acute post-injury phase, platelets develop a state of impaired ex vivo agonist responsiveness independent of platelet count, associated with systemic coagulopathy and mortality risk. In patients surviving the initial insult, platelets become hyper-responsive, associated with increased risk of thrombotic events. Beyond coagulation, platelets constitute part of a sterile inflammatory response to injury: both directly through release of immunomodulatory molecules, and indirectly through modifying behavior of innate leukocytes. Both procoagulant and proinflammatory aspects have implications for secondary organ injury and multiple-organ dysfunction syndromes. This review details our current understanding of adaptive and maladaptive alterations in platelet biology induced by severe trauma, mechanisms underlying these alterations, potential platelet-focused therapies, and existing knowledge gaps and their research implications.

A Comparison of Transfusion-Related Adverse Reactions Among Apheresis Platelets, Whole Blood-Derived Platelets, and Platelets Subjected to Pathogen Reduction Technology as Reported to the National Healthcare Safety Network Hemovigilance Module

Despite advances in transfusion safety, concerns with safety of platelet transfusions remain including platelet-related sepsis and higher reaction rates observed among patients receiving apheresis platelets (APLTs). National Healthcare Safety Network (NHSN) Hemovigilance Module (HM) data were analyzed to quantify the burden and severity of adverse reactions occurring from APLTs and whole blood-derived platelets (WBD-PLTs). Facilities participating in NHSN HM during 2010-2018 were included. Adverse reaction rates (number per 100,000 components transfused) were calculated for APLTs and WBD-PLTs stratified by severity, use of platelet additive solution (PAS), and pathogen reduction technology (PRT). Chi-square tests were used to compare rates. During the study interval, 2,000,589 platelets were transfused: 1,435,154 APLTs; 525,902 WBD-PLTs; and among APLTs, 39,533 PRT-APLTs. APLT adverse reaction rates were higher (478 vs 70/ 100,000, P< .01) and more often serious (34 vs 6/100,000; P< .01) compared with WBD-PLTs. Adverse reactions were higher among PRT-APLTs (572/100,000) and were less often serious (18/100,000) compared with non-PRT-APLTs (35/100,000) although this association was not statistically significant. Among components implicated in adverse reactions, 92% of APLTs were suspended in plasma. Compared with PRT-APLTs stored in PAS, rates were higher among units stored in plasma (760 vs 525/100,000). Most serious reactions (75%) were allergic. No transfusion-transmitted infections were reported among PRT-APLTs. APLTs were associated with a 6-fold and 2-fold higher serious adverse reaction risks compared with WBD-PLTs and PRT-APLTs, respectively. These findings demonstrate the importance of monitoring transfusion-related adverse reactions to track the safety of platelet transfusions and quantify the impact of mitigation strategies through national hemovigilance systems.

Fluids of the Future

Fluids are a vital tool in the armament of acute care clinicians in both civilian and military resuscitation. We now better understand complications from inappropriate resuscitation with currently available fluids; however, fluid resuscitation undeniably remains a life-saving intervention. Military research has driven the most significant advances in the field of fluid resuscitation and is currently leading the search for the fluids of the future. The veterinary community, much like our civilian human counterparts, should expect the fluid of the future to be the fruit of military research. The fluids of the future not only are expected to improve patient outcomes but also be field expedient. Those fluids should be compatible with military environments or natural disaster environments. For decades, military personnel and disaster responders have faced the peculiar demands of austere environments, prolonged field care, and delayed evacuation. Large scale natural disasters present field limitations often similar to those encountered in the battlefield. The fluids of the future should, therefore, have a long shelf-life, a small footprint, and be resistant to large temperature swings, for instance. Traumatic brain injury and hemorrhagic shock are the leading causes of preventable death for military casualties and a significant burden in civilian populations. The military and civilian health systems are focusing efforts on field-expedient fluids that will be specifically relevant for the management of those conditions. Fluids are expected to be compatible with blood products, increase oxygen-carrying capabilities, promote hemostasis, and be easy to administer in the prehospital setting, to match the broad spectrum of current acute care challenges, such as sepsis and severe systemic inflammation. This article will review historical military and civilian contributions to current resuscitation strategies, describe the expectations for the fluids of the future, and describe select ongoing research efforts with a review of current animal data.

Ontogeny of platelet function

Although the hemostatic potential of adult platelets has been investigated extensively, regulation of platelet function during fetal life is less clear. Recent studies have provided increasing evidence for a developmental control of platelet function during fetal ontogeny. Fetal platelets feature distinct differences in reactive properties compared with adults. These differences very likely reflect a modified hemostatic and homeostatic environment in which platelet hyporeactivity contributes to prevent pathological clot formation on the one hand but still ensures sufficient hemostasis on the other hand. In this review, recent findings on the ontogeny of platelet function and reactivity are summarized, and implications for clinical practice are critically discussed. This includes current platelet-transfusion practice and its potential risk in premature infants and neonates.

Overview of Plasma and Platelet Transfusions in Critically Ill Children

Critically ill children are a unique population who frequently receive plasma and platelet transfusions for both active bleeding and mitigation of bleeding risk. While these products are frequently administered, transfusion indications in this population remain unclear, and practice varies across institutions and providers. In this manuscript, we will outline the current evidence regarding plasma and platelet transfusions for hemostasis in the pediatric intensive care setting. For both products, we will describe the product composition, epidemiology, and product indications and discuss the potential risks and benefits involved with the transfusion. We will also discuss knowledge gaps and future areas of research.

Platelet Transfusion Related Panophthalmitis and Endophthalmitis in Patients with Dengue Hemorrhagic Fever

Dengue is a vector-borne viral illness of major public health importance. It is endemic in many parts of India and also causes frequent epidemics. Platelet transfusions are given in severe cases of dengue fever to treat and prevent hemorrhagic complications. Here, we report three patients in North India with development of panophthalmitis and endophthalmitis shortly after receiving platelet transfusion.

Preoperative Immune Response is Associated with Perioperative Transfusion Requirements in Glioma Surgery

Immunosuppression induced by transfusion causes postoperative adverse events including poor prognosis in cancer, but data on influence of the immune response on blood transfusion requirements during perioperative period are limited. The aim of this study was to investigate whether the preoperative immune response is associated with perioperative blood cell transfusion in a glioma surgical patient population. The authors identified 321 cases of surgery for treatment of glioma. Patient variables, preoperative laboratory variables (hemoglobin, platelet count, activated partial thromboplastin time, prothrombin time, hematocrit, red and white blood cell count), and transfusions were registered. Plasma concentration of Th-associated cytokines was measured by flow cytometry. Multivariable regression analysis and receiver operating characteristic curve were undertaken to identify predictors of transfusion. Of 321 patients, 157 (48.90%) received red blood cells transfusion. The mean age is significantly higher in transfusion group compared to no transfusion group, while postoperative hospital stay, preoperative hemoglobin, prothrombin time, activated partial thromboplastin time, platelet count, red and white blood cell count and hematocrit of patients did not differ significantly between the two groups. No significant differences of IL-2, -4, -6, -10 and INF-γ concentration were observed between transfusion and no transfusion group. The concentration of TNF and IL-17A was significantly lower in transfusion patients than in the no transfusion subjects. Low plasma TNF and IL-17A levels predicted high perioperative transfusion rate, the combination of them enlarged the prognostic accuracy of testing. Our study demonstrates that the preoperative immune response influences transfusion requirements, and TNF and IL-17 are important predictive risk factors for perioperative use of blood components in glioma patients.

Assessment of Time-Dependent Platelet Activation Using Extracellular Vesicles, CD62P Exposure, and Soluble Glycoprotein V Content of Platelet Concentrates with Two Different Platelet Additive Solutions

Novel analytical measures are needed to accurately monitor the properties of platelet concentrates (PCs). Since activated platelets produce platelet-derived extracellular vesicles (EVs), analyzing EVs of PCs may provide additional information about the condition of platelets. The prospect of using EVs as an auxiliary measure of platelet activation state was investigated by examining the effect of platelet additive solutions (PASs) on EV formation and platelet activation during PC storage. The time-dependent activation of platelets in PCs with PAS-B or with the further developed PAS-E was compared by measuring the exposure of CD62P by flow cytometry and the content of soluble glycoprotein V (sGPV) of PCs by an immunoassay. Changes in the concentration and size distribution of EVs were determined using nanoparticle tracking analysis. A time-dependent increase in platelet activation in PCs was demonstrated by increased CD62P ex-posure, sGPV content, and EV concentration. Using these strongly correlating parameters, PAS-B platelets were shown to be more activated compared to PAS-E platelets. Since the EV concentration correlated well with the established platelet activation markers CD62P and sGPV, it could potentially be used as a complementary parameter for platelet activation for PCs. More detailed characterization of the resulting EVs could help to understand how the PC components contribute the functional effects of transfused PCs.

Intravenous administration of synthetic platelets (SynthoPlate) in a mouse liver injury model of uncontrolled hemorrhage improves hemostasis

BACKGROUND

Clinical resuscitative treatment of traumatic hemorrhage involves transfusion of RBC, platelets and plasma in controlled ratios. However, use of such blood components, especially platelets, present many challenges including availability, portability, contamination risks, and short shelf-life, which limit the use of platelet transfusions outside of large trauma centers such as remote civilian hospitals and austere prehospital settings. This has prompted significant research in platelet substitutes that may resolve the above issues while providing platelet-mimetic hemostatic action. In this framework, we have developed a synthetic platelet surrogate, SynthoPlate, by integrative decoration of platelet function mimetic peptides on a biocompatible lipid nanovesicle platform. We have previously demonstrated hemostatic capability of SynthoPlate in correcting tail-bleeding time in thrombocytopenic mice. Building on this, we hypothesized that SynthoPlate transfusion would decrease bleeding in a murine model of acute hemorrhagic shock.

METHODS

A validated model of uncontrolled intraperitoneal hemorrhage, via liver laceration was used to induce hemorrhagic shock in mice. SynthoPlate, control (unmodified) particles, and normal saline were administered as pretreatment and recue infusions to mice undergoing liver laceration and evaluated for hemostatic benefit by determining differences in blood loss and monitoring real-time hemodynamic data.

RESULTS

Pretreatment SynthoPlate transfusion resulted in significant reduction of blood loss following hemorrhage, compared with control particles or normal saline treatment (0.86 ± 0.16 g control particles [CP] vs. 0.84 ± 0.13 g normal saline [NS] vs. 0.68 ± 0.09 g SynthoPlate, p < 0.005). SynthoPlate transfused mice demonstrated improved hemodynamics taking significantly longer to develop post-injury hypotension (168.3 ± 106.6 seconds CP vs. 137 ± 58 seconds NS vs. 546.7 ± 329.8 seconds SynthoPlate, p < 0.05). SynthoPlate infusion following liver laceration, that is, rescue transfusion, also resulted in a significant decrease in blood loss (0.89 ± 0.17 g CP vs. 0.92 ± 0.19 g NS vs. 0.69 ± 0.18 g SynthoPlate, p < 0.05).

CONCLUSION

Transfusion of SynthoPlate particles reduces blood loss in a murine model of liver injury, and SynthoPlates may represent a viable transfusion product for the mitigation of blood loss in acute, severe hemorrhagic shock.

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.

rBPI21 (Opebacan) Promotes Rapid Trilineage Hematopoietic Recovery in a Murine Model of High-Dose Total Body Irradiation

The complexity of providing adequate care after radiation exposure has drawn increasing attention. While most therapeutic development has focused on improving survival at lethal radiation doses, acute hematopoietic syndrome (AHS) occurs at substantially lower exposures. Thus, it is likely that a large proportion of such a radiation-exposed population will manifest AHS of variable degree and that the medical and socioeconomic costs of AHS will accrue. Here, we examined the potential of rBPI21 (opebacan), used without supportive care, to accelerate hematopoietic recovery after radiation where expected survival was substantial (42-75%) at 30 days). rBPI21 administration was associated with accelerated recovery of hematopoietic precursors and normal marrow cellularity, with increases in megakaryocyte numbers particularly marked. This translated into attaining normal trilineage peripheral blood counts 2-3 weeks earlier than controls. Elevations of hematopoietic growth factors observed in plasma and the marrow microenvironment suggest the mechanism is likely multifactorial and not confined to known endotoxin-neutralizing and cytokine down-modulating activities of rBPI21 . These observations deserve further exploration in radiation models and other settings where inadequate hematopoiesis is a prominent feature. These experiments also model the potential of therapeutics to limit the allocation of scarce resources after catastrophic exposures as an endpoint independent of lethality mitigation. This article is protected by copyright. All rights reserved.

Big data modeling to predict platelet usage and minimize wastage in a tertiary care system

In modern hospital systems where complicated, severely ill patient populations are the norm, there is currently no reliable way to forecast the use of perishable medical resources to enable a smart and economic way to deliver optimal patient care. We here demonstrate a statistical model using hospital patient data to quantitatively forecast, days in advance, the need for platelet transfusions. This approach can be leveraged to significantly decrease platelet wastage, and, if adopted nationwide, would save approximately 80 million dollars per year. We believe our approach can be generalized to all other aspects of patient care involving timely delivery of perishable medical resources.

Maintaining a robust blood product supply is an essential requirement to guarantee optimal patient care in modern health care systems. However, daily blood product use is difficult to anticipate. Platelet products are the most variable in daily usage, have short shelf lives, and are also the most expensive to produce, test, and store. Due to the combination of absolute need, uncertain daily demand, and short shelf life, platelet products are frequently wasted due to expiration. Our aim is to build and validate a statistical model to forecast future platelet demand and thereby reduce wastage. We have investigated platelet usage patterns at our institution, and specifically interrogated the relationship between platelet usage and aggregated hospital-wide patient data over a recent consecutive 29-mo period. Using a convex statistical formulation, we have found that platelet usage is highly dependent on weekday/weekend pattern, number of patients with various abnormal complete blood count measurements, and location-specific hospital census data. We incorporated these relationships in a mathematical model to guide collection and ordering strategy. This model minimizes waste due to expiration while avoiding shortages; the number of remaining platelet units at the end of any day stays above 10 in our model during the same period. Compared with historical expiration rates during the same period, our model reduces the expiration rate from 10.5 to 3.2%. Extrapolating our results to the ∼2 million units of platelets transfused annually within the United States, if implemented successfully, our model can potentially save ∼80 million dollars in health care costs.

Towards pathogen inactivation of red blood cells and whole blood targeting viral DNA/RNA: design, technologies, and future prospects for developing countries

Over 110 million units of blood are collected yearly. The need for blood products is greater in developing countries, but so is the risk of contracting a transfusion-transmitted infection. Without efficient donor screening/viral testing and validated pathogen inactivation technology, the risk of transfusion-transmitted infections correlates with the infection rate of the donor population. The World Health Organization has published guidelines on good manufacturing practices in an effort to ensure a strong global standard of transfusion and blood product safety. Sub-Saharan Africa is a high-risk region for malaria, human immunodeficiency virus (HIV), hepatitis B virus and syphilis. Southeast Asia experiences high rates of hepatitis C virus. Areas with a tropical climate have an increased risk of Zika virus, Dengue virus, West Nile virus and Chikungunya, and impoverished countries face economical limitations which hinder efforts to acquire the most modern pathogen inactivation technology. These systems include Mirasol® Pathogen Reduction Technology, INTERCEPT®, and THERAFLEX®. Their procedures use a chemical and ultraviolet or visible light for pathogen inactivation and significantly decrease the threat of pathogen transmission in plasma and platelets. They are licensed for use in Europe and are used in several other countries. The current interest in the blood industry is the development of pathogen inactivation technologies that can treat whole blood (WB) and red blood cell (RBC). The Mirasol system has recently undergone phase III clinical trials for treating WB in Ghana and has demonstrated some efficacy toward malaria inactivation and low risk of adverse effects. A 2nd-generation of the INTERCEPT® S-303 system for WB is currently undergoing a phase III clinical trial. Both methodologies are applicable for WB and components derived from virally reduced WB or RBC.

Extracellular vesicles as potential biomarkers of acute graft-vs-host disease

Acute graft-vs-host disease (GVHD) is a serious complication after allografting. We carried out an exploratory study to investigate a potential correlation of surface antigens on extracellular vesicles (EVs) and acute GVHD. EVs were extracted from serum samples from 41 multiple myeloma patients who underwent allografting. EVs were characterized by flow cytometry using a panel of 13 antibodies against specific membrane proteins that were reported to be predictive of acute GVHD. We observed a correlation between three potential biomarkers expressed on EV surface and acute GVHD onset by both logistic regression analysis and Cox proportional hazard model. In our study, CD146 (MCAM-1) was correlated with an increased risk-by almost 60%-of developing GVHD, whereas CD31 and CD140-α (PECAM-1 and PDGFR-α) with a decreased risk-by almost 40 and 60%, respectively. These biomarkers also showed a significant change in signal level from baseline to the onset of acute GVHD. Our novel study encourages future investigations into the potential correlation between EVs and acute GVHD. Larger prospective multicenter studies are currently in progress.

Duration of red blood cell storage and inflammatory marker generation

Red blood cell (RBC) transfusion is a life-saving treatment for several pathologies. RBCs for transfusion are stored refrigerated in a preservative solution, which extends their shelf-life for up to 42 days. During storage, the RBCs endure abundant physicochemical changes, named RBC storage lesions, which affect the overall quality standard, the functional integrity and in vivo survival of the transfused RBCs. Some of the changes occurring in the early stages of the storage period (for approximately two weeks) are reversible but become irreversible later on as the storage is extended. In this review, we aim to decipher the duration of RBC storage and inflammatory marker generation. This phenomenon is included as one of the causes of transfusion-related immunomodulation (TRIM), an emerging concept developed to potentially elucidate numerous clinical observations that suggest that RBC transfusion is associated with increased inflammatory events or effects with clinical consequence.

Flow cytometry analysis of platelet populations: usefulness for monitoringthe storage lesion in pooled buffy-coat platelet concentrates

BACKGROUND

Early detection of the platelet storage lesion is still a challenge in transfusion practice. Using flow cytometry, we evaluated the appearance of the storage lesion, based on the expression of platelet activation markers, in total platelets and platelet populations.

MATERIALS AND METHODS

Buffy-coat-derived platelet concentrates were stored under standard conditions for 5 days. The expression of activation antigens CD42b, CD36, CD62p and phosphatidylserine on total platelets and populations of small, medium-sized and large platelets was analysed by flow cytometry on storage days 1, 3 and 5.

RESULTS

The activation/lesion on total platelets and each platelet population was detected on storage day 3, by the increased expression of CD36. On the same day, increased expression of CD42b and CD62p was detected, but only on large platelets. Small and medium-sized platelets had increased CD62p expression only on day 5. Externalisation of phosphatidylserine was not detected.

DISCUSSION

Evaluation of the level of expression of various activation markers on different platelet populations could be an additional valid analysis in cell quality control of platelet concentrates, and in the assessment of novel approaches to platelet concentrate manipulation.

Transfusion as an Inflammation Hit: Knowns and Unknowns

Transfusion of blood cell components is frequent in the therapeutic arsenal; it is globally safe or even very safe. At present, residual clinical manifestations are principally inflammatory in nature. If some rare clinical hazards manifest as acute inflammation symptoms of various origin, most of them linked with conflicting and undesirable biological material accompanying the therapeutic component (infectious pathogen, pathogenic antibody, unwanted antigen, or allergen), the general feature is subtler and less visible, and essentially consists of alloimmunization or febrile non-hemolytic transfusion reaction. The present essay aims to present updates in hematology and immunology that help understand how, when, and why subclinical inflammation underlies alloimmunization and circumstances characteristic of red blood cells and – even more frequently – platelets that contribute inflammatory mediators. Modern transfusion medicine makes sustained efforts to limit such inflammatory hazards; efforts can be successful only if one has a clear view of each element’s role.