A third episode of transfusion-derived vCJD

Dried Plasma for Major Trauma: Past, Present, and Future

Uncontrollable bleeding is recognized as the leading cause of preventable death among trauma patients. Early transfusion of blood products, especially plasma replacing crystalloid and colloid solutions, has been shown to increase survival of severely injured patients. However, the requirements for cold storage and thawing processes prior to transfusion present significant logistical challenges in prehospital and remote areas, resulting in a considerable delay in receiving thawed or liquid plasma, even in hospitals. In contrast, freeze- or spray-dried plasma, which can be massively produced, stockpiled, and stored at room temperature, is easily carried and can be reconstituted for transfusion in minutes, provides a promising alternative. Drawn from history, this paper provides a review of different forms of dried plasma with a focus on in vitro characterization of hemostatic properties, to assess the effects of the drying process, storage conditions in dry form and after reconstitution, their distinct safety and/or efficacy profiles currently in different phases of development, and to discuss the current expectations of these products in the context of recent preclinical and clinical trials. Future research directions are presented as well.

Problems with precaution: the transfusion medicine experience

The precautionary principle is a dominant paradigm governing risk-based decision-making. Today, there are increasing pressures to re-examine aggressive precautionary approaches, and to assess how the principle should be applied in the modern system. In this paper, we examined three key applications of precautionary approaches in the field of transfusion medicine to provide insight into the risks and benefits of these approaches. The three case studies examined were the donor deferral policies to safeguard against transfusion transmission of human immunodeficiency virus, variant Creutzfeldt-Jacob disease, and, lastly, xenotropic murine leukemia virus-related virus. Characterization of precautionary applications was conducted using an embedded case study design. Our findings indicate that transfusion transmission mitigation strategies have become increasingly aggressive in the face of theoretical risks. In contrast, the review processes for implementation and reversal of precautionary policies have been slow, and historical donor deferral policies are still in place today. Application of precautionary approaches has proved challenging with both benefits and pitfalls. In light of emerging threats to the blood system, policy-makers should consider the implementation of frameworks to guide the appropriate application of precaution in transfusion medicine in the future.

[Acquired human prion diseases--past and present issues]

Transmissible spongiform encephalopathies, or prion diseases, are fatal neurodegenerative disorders. In aetiological viewpoint, human prion diseases are classified into 1) sporadic Creutzfeldt-Jakob disease (CJD) which comprises 80-90% of the total population of human prion disaeses, 2) inherited forms, and 3) acquired types by prion-contaminated surgical instruments, biopharmaceuticals or foodstuffs. The diseases cause an accumulation of the disease-associated form(s) of prion protein (PrP(Sc)) in the central nervous system. PrP(Sc) is regarded as the entity of prion agents and generally exerts infectivity, irrespective of its origin being from the sporadic cases or the inherited cases. Variant CJD (vCJD), first identified in the United Kingdom (UK) in 1996, is an acquired type of human CJD by oral intake of BSE prion. Cumulative numbers of 215 patients in the world have been reported for definite or probable vCJD cases according to the UK National Creutzfeldt-Jakob Disease Surveillance Unit by September, 2009. Different from sporadic CJD cases, vCJD patients show an accumulation of PrP(Sc) in spleen and tonsils. Such distribution of PrP(Sc) in lymphoid tissues raised clinical concern about the potential infectivity in the blood or blood components used for blood transfusion. To date, five instances of probable transfusion-mediated transmission of vCJD prion have been found in UK. Here we review the past and the present issues about the acquired human prion diseases.

Recombinant factor VIII in the management of hemophilia A: current use and future promise

Hemophilia A is a rare inherited bleeding disorder due to mutation of the gene that encodes the coagulation protein factor VIII. Historically, prior to the availability of treatment with factor VIII preparations, most boys died from uncontrolled bleeding, either spontaneous bleeding or after injury, before reaching 20 years of age. One of the most impressive triumphs of modern medicine is that with current recombinant factor VIII replacement therapy, a boy born in the 21st century with severe hemophilia A can anticipate a normal life expectancy with essentially no permanent complications from bleeding. For severe hemophilia A, current optimal treatment should have two goals: first, to provide sufficient factor VIII to prevent spontaneous bleeding, and second, to provide sufficient factor VIII to have normal coagulation function after any trauma. However, the replacement therapy requires tremendous resources for effective use, and remains extraordinarily expensive. Thus there are opportunities for further advances in therapy for hemophilia A. Two major concerns continue to trouble current optimal treatment approaches: some patients will develop neutralizing antibodies during the first 50 infusions of therapeutic factor VIII, and second, to administer therapeutic factor VIII every other day in young boys often requires placement of a central venous access device, and such use carries the life-threatening risks of infection and thrombosis. Because of the effectiveness of current therapy, any new developments in treatment will require significant concerns for safety, both immediate and in the long term. A number of research groups seek to prolong the biological efficacy of infused recombinant factor VIII. Currently, one such promising development is in the advanced stages of clinical trial. The goals will be to improve further the quality of life of an individual with severe hemophilia A, and to reduce the burden of current treatment strategies on families and medical resources. Hopefully, the hemophilia community will continue to participate actively in the clinical trials needed to address these new challenges.

From mad cows to sensible blood transfusion: the risk of prion transmission by labile blood components in the United Kingdom and in France

Transfusion transmission of the prion, the agent of variant Creutzfeldt-Jakob disease (vCJD), is now established. Subjects infected through food may transmit the disease through blood donations. The two nations most affected to date by this threat are the United Kingdom (UK) and France. The first transfusion cases have been observed in the UK over the past 5 years. In France, a few individuals who developed vCJD had a history of blood donation, leading to a risk of transmission to recipients, some of whom could be incubating the disease. In the absence of a large-scale screening test, it is impossible to establish the prevalence of infection in the blood donor population and transfused patients. This lack of a test also prevents specific screening of blood donations. Thus, prevention of transfusion transmission essentially relies at present on deferral of "at-risk" individuals. Because prions are present in both white blood cells and plasma, leukoreduction is probably insufficient to totally eliminate the transfusion risk. In the absence of a screening test for blood donations, recently developed prion-specific filters could be a solution. Furthermore, while the dietary spread of vCJD seems efficiently controlled, uncertainty remains as to the extent of the spread of prions through blood transfusion and other secondary routes.

Anemia and transfusions in patients undergoing surgery for cancer

Preoperative, operative, and postoperative factors may all contribute to high rates of anemia in patients undergoing surgery for cancer. Allogeneic blood transfusion is associated with both infectious risks and noninfectious risks such as human errors, hemolytic reactions, transfusion-related acute lung injury, transfusion-associated graft-versus-host disease, and transfusion-related immune modulation. Blood transfusion may also be associated with increased risk of cancer recurrence. Blood-conservation measures such as preoperative autologous donation, acute normovolemic hemodilution, perioperative blood salvage, recombinant human erythropoietin (epoetin alfa), electrosurgical dissection, and minimally invasive surgical procedures may reduce the need for allogeneic blood transfusion in elective surgery. This review summarizes published evidence of the consequences of anemia and blood transfusion, the effects of blood storage, the infectious and noninfectious risks of blood transfusion, and the role of blood-conservation strategies for cancer patients who undergo surgery. The optimal blood-management strategy remains to be defined by additional clinical studies. Until that evidence becomes available, the clinical utility of blood conservation should be assessed for each patient individually as a component of preoperative planning in surgical oncology.