The role and importance of epidemiology in transfusion medicine.

Transfusion therapy is an indispensable form of treatment, and an important element of the public health system. Due to its origin, blood's clinical use is associated with various risks that may cause adverse reactions and events. Progress in quality and safety of blood components has eliminated numerous risks, especially those of infectious origin. However, some risks cannot be predicted, while others cannot always be prevented. Globalisation and climate change constantly favour the spread of infectious agents. Against this, epidemiology plays a central role in ensuring the safety of transfusion treatment, by continuous surveillance and timely identification of risks, and in the development of routine and additional tests as measures for risk mitigation. As a quantitative discipline based on research methods, epidemiology is a method of reasoning; it relies on the generation and testing of hypotheses; it utilises other scientific resources, particularly in the field of blood donation and blood transfusion, thus having many applications. The main focus falls on transfusion-transmissible infections, and on environmental or occupational diseases, injuries, disabilities and death causes at large. The practice of epidemiology relies on a systematic approach and measurement of disease frequencies. Surveillance is a key element, involving continuously gathering, analysing, and evaluating data regarding diseases, morbidity and mortality, and disseminating the conclusions of the analyses to relevant competent authorities; in this way, action is taken for disease prevention and control. Surveillance systems also provide an important tool for risk assessment, a method to assess and characterise the critical parameters in the functionality of equipment, systems or processes of using scientific data in order to estimate the magnitude of any health effect that derives from decisions of policy makers. Epidemiological surveillance, particularly for the incidence of adverse reactions and adverse events associated with blood transfusion at the national and international levels, has demonstrated the importance of multidisciplinary cooperation between blood and public health services.

Bioactive lipids as biomarkers of adverse reactions associated with apheresis platelet concentrate transfusion.

Platelet concentrate (PC) transfusion seeks to provide haemostasis in patients presenting severe central thrombocytopenia or severe bleeding. PCs may induce adverse reactions (AR) that can occasionally be severe (SAR). PCs contain active biomolecules such as cytokines and lipid mediators. The processing and storage of PCs creates so-called structural and biochemical storage lesions that accumulate when blood products reach their shelf life. We sought to investigate lipid mediators as bioactive molecules of interest during storage and review associations with adverse reactions post-transfusion. To facilitate understanding, we focused on single donor apheresis (SDA) PCs with approximately 31.8% of PCs being delivered in our setting. Indeed, pooled PCs are the most widely transfused products, but the study of a single donor lipid mediator is easier to interpret. We are investigating key lipid mediators involved in AR. Adverse reactions were closely monitored in accordance with current national and regional haemovigilance protocols. Residual PCs were analysed post-transfusion in a series of observations, both with and without severe reactions in recipients. A decrease in the lysophosphatidylcholine species to produce the lysophosphatidic acid species has been observed during storage and in the case of AR. Lysophosphatidic acid increased with primarily platelet-inhibitor lipids. Anti-inflammatory platelet-induced inhibition lipids were weakly expressed in cases of severe adverse reactions. We therefore propose that a decrease in lysophosphatidylcholine and an increase in lysophosphatidic acid can prospectively predict serious adverse transfusion reactions.

Ethics in transfusion medicine: Are the intricate layers of ethics all universal? A global view.

Ethical principles have been considered, and in several respects regulated, along the entire blood procurement chain from donor motivation to transfusion to the patient. Consent of donors and voluntary non-remunerated donation are fields which have been addressed by codes of ethics and legislation. Caring for donor health is an area of further development of ethical standards. In part, blood products have also become a market, where commercial principles may synergize, but also creating issues in equality and maintaining human dignity that challenge societal solutions. At the bedside, the main global challenge remains to procure enough blood products for each patient in medical need. Allocation of rare blood, ethical evaluation of transfusion triggers, attitudes towards refusing blood transfusion and provision of blood products to remote settings are areas which should receive consideration.

Education in transfusion medicine, Part III - The importance of haemovigilance education.

According to the literature, there are significant differences in the availability of education and training in transfusion medicine worldwide, with significant heterogeneity in the existing curricula. Recognising the need for education with the aim of achieving globally standardised competencies in transfusion medicine, a group of experts collaborating in the European and Mediterranean Initiative in Transfusion medicine (EMITm) proposed a process of incremental training and education. Subsequent to two previous papers published by this group on general education in transfusion medicine, this paper specifically refers to the field of education in haemovigilance. This topic is of particular importance when one considers the role of haemovigilance in improving the safety of transfusion practice, and the fact that this role can only be realised through the cooperation of all participants in the transfusion chain. In addition to promoting the importance of education in haemovigilance, this paper provides an overview of the available literature on this topic and proposes an education programme on haemovigilance for medical students and residents.

Thirty years of hemovigilance - Achievements and future perspectives.

Since its emergence in the early 1990s, hemovigilance has gradually evolved from a blood safety concept focused on surveillance of adverse reactions and events in patients, to a well-defined system that monitors the entire transfusion chain and improves its safety. The importance of hemovigilance has been recognized globally in a relatively short time, but the level of its implementation varies significantly between countries. The cooperation of international organizations has significantly contributed to the promotion, implementation, and education in this field. Thanks to initiatives taken, the safety of transfusion practice has been improved in many segments, primarily related to the risks of adverse events in recipients of blood components. In parallel with changing transfusion practice, the hemovigilance process has also matured. In addition to the reduction of existing risks and the early detection of emerging risks, hemovigilance has also embraced the principles of patient blood management. Research in hemovigilance is more increasingly focused on specific categories of patients, specific blood components and methods of their preparation, rare reactions, and transfusion efficacy and efficiency. A proactive approach and use of big data can play an important role in achieving these goals. Additional and sustained efforts should be made to prevent underreporting of events and to improve data comparability through clear definitions and grading systems. This review provides a historical overview of hemovigilance and its achievements, current challenges, and future plans.

How to improve issuing, transfusion and follow-up of blood components in Southern and Eastern Mediterranean countries? A benchmark assessment.

To determine the existence of guidelines regarding the appropriate clinical use of blood and blood components, transfusion requests, and blood issuing/reception documents and procedures. The different bedside transfusion organizations/processes and hemovigilance are also analyzed. The ultimate objective is to identify safe potential options in order to improve blood safety at the lowest cost. Data emanating from eight Arabic eastern/southern Mediterranean countries who responded to five surveys were collected and tabulated. National recommendations for the clinical use of blood components especially for hemoglobinopathies are lacking in some countries. In matter of good practices in the prescription, issuing and reception of BCs, efforts were made either on national or local basis. Procedures regarding patient information and ethical issues are still lacking. Almost all Mediterranean countries apply two blood testing procedures on each patient sample. Only Morocco, Tunisia and Algeria perform bed side blood group testing; Egypt and Lebanon perform antibody screen and antiglobulin cross matching universally. Automation for blood testing is insufficiently implemented in almost all countries and electronic release is almost absent. National hemovigilance policy is implemented in Tunisia, Morocco, and Lebanon but the reporting system remains inoperative. Insufficient resources severely hinders the implementation of expensive procedures and programs; however, the present work identifies safe procedures that might save resources to improve other parts in the transfusion process (e.g. electronic release to improve safety in issuing). Moreover, setting up regulations regarding ethics in transfusing recipients along with local transfusion committees are crucially needed to implement hemovigilance in transfusion practice.

Lipidomic analysis of differently prepared platelet concentrates in additive solution during storage.

BACKGROUND: Structural and biochemical changes in stored platelets are influenced by collection and processing methods. Lesions may appear during platelet concentrate storage, some of which may be involved in adverse transfusion reactions. The preparation and storage of platelet concentrates (PC) may modify and even damage the lipid mediator content. The aim of this study was to investigate the lipidomic profile identified in the supernatants of PCs according to processing and storage conditions, both after leukocyte filtration and contained in platelet additive solution (PAS), comparing single donor apheresis (SDA) products with pooled buffy coat (BC) products. MATERIALS AND METHODS: We investigated the accumulation of various lipid mediators including lysophospholipids (LP) and eicosanoids in SDA and BC products stored for 0-5 days. All products were processed following French Blood Establishment (EFS) procedures in accordance with EDQM/GTS European Standards. Both SDA and BC were leukocyte reduced and conserved in 35% autologous donor plasma and 65% platelet additive solution. Lipidomic analysis was performed on PC supernatants using LS/MS spectrometry. RESULTS: Our data demonstrate that lysophosphatidylcholine (LPC) levels were higher in BCs compared to SDAs, with no difference in lysophosphatidic acid (LPA) expression between the two preparation methods. Results for other eicosanoids showed greater similarity; indeed, no clear pattern emerged from analysis of eicosanoids in terms of storage time and process. In general, we observed longitudinal lipid mediator modulation for both SDAs and BCs, particularly at later time points. DISCUSSION: The expression of LPC and some eicosanoids in BCs could be used as novel biomarkers of PC quality. Future studies are needed to explore their impact on adverse transfusion reactions.

An overview of red blood cell and platelet alloimmunisation in transfusion.

Post-transfusion alloimmunisation is the main complication of all those observed after one or more transfusion episodes. Alloimmunisation is observed after the transfusion of red blood cell concentrates but also of platelet concentrates. Besides alloimmunisation due to antigens carried almost exclusively by red blood cells such as those of the Rhesus-Kell system, alloimmunisation often raises against HLA antigens; the main responsibility for that, apart from platelet transfusions, lies with residual leukocytes in the products transfused, hence the central importance of effective leukoreduction right from the blood product preparation stage. Alloimmunization is not restricted to transfusion, but it is also observed during pregnancies, carrying out microtransfusions of blood from the fetus immunizing the mother through the placenta (in a retrograde way). Preexisting maternal-fetal immunization can complicate a transfusion program and intensify the creation of alloantibodies in several blood and tissue group systems. The occurrence of autoantibodies, created by several pathogenic reasons, can also interfere with the propensity of certain recipients of blood components to produce alloantibodies. The genetic condition of individuals is in fact strongly linked to the ability or not to recognize antigenic variants foreign to their own biological program and mount an alloimmune response. Some hemoglobin diseases, in carriers of which transfusions can be iterative and lifelong, are complicated by frequent alloimmunizations and amplification of the complications of these alloimmunizations, imposing even stricter transfusion rules. This review details the mechanisms favoring the occurrence of alloimmunization and the immunological principles for the production of molecular and cellular tools for alloimmunization. It concludes with the main preventive measures available to limit the occurrence of these frequent complications of varying severity but sometimes severe.

Platelets as Key Factors in Inflammation: Focus on CD40L/CD40.

Platelets are anucleate cytoplasmic fragments derived from the fragmentation of medullary megakaryocytes. Activated platelets adhere to the damaged endothelium by means of glycoproteins on their surface, forming the platelet plug. Activated platelets can also secrete the contents of their granules, notably the growth factors contained in the α-granules, which are involved in platelet aggregation and maintain endothelial activation, but also contribute to vascular repair and angiogenesis. Platelets also have a major inflammatory and immune function in antibacterial defence, essentially through their Toll-like Receptors (TLRs) and Sialic acid-binding immunoglobulin-type lectin (SIGLEC). Platelet activation also contributes to the extensive release of anti- or pro-inflammatory mediators such as IL-1ß, RANTES (Regulated on Activation, Normal T Expressed and Secreted) or CD154, also known as the CD40-ligand. Platelets are involved in the direct activation of immune cells, polynuclear neutrophils (PNNs) and dendritic cells via the CD40L/CD40 complex. As a general rule, all of the studies presented in this review show that platelets are capable of covering most of the stages of inflammation, primarily through the CD40L/CD40 interaction, thus confirming their own role in this pathophysiological condition.

Platelet Innate Immune Receptors and TLRs: A Double-Edged Sword.

Platelets are hematopoietic cells whose main function has for a long time been considered to be the maintenance of vascular integrity. They have an essential role in the hemostatic response, but they also have functional capabilities that go far beyond it. This review will provide an overview of platelet functions. Indeed, stress signals may induce platelet apoptosis through proapoptotis or hemostasis receptors, necrosis, and even autophagy. Platelets also interact with immune cells and modulate immune responses in terms of activation, maturation, recruitment and cytokine secretion. This review will also show that platelets, thanks to their wide range of innate immune receptors, and in particular toll-like receptors, and can be considered sentinels actively participating in the immuno-surveillance of the body. We will discuss the diversity of platelet responses following the engagement of these receptors as well as the signaling pathways involved. Finally, we will show that while platelets contribute significantly, via their TLRs, to immune response and inflammation, these receptors also participate in the pathophysiological processes associated with various pathogens and diseases, including cancer and atherosclerosis.