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Approximately five decades ago, alloimmunization to human leukocyte antigens (HLA) and platelet refractoriness were recognized as potentially serious complications of platelet transfusions. The mechanisms that result in stimulating immunity against blood products are still incompletely understood but are related to both the composition of the donor product transfused and the immune status of the r

Transfusion-related acute lung injury (TRALI) is a leading cause of transfusion-associated mortality that can occur with any type of transfusion and is thought to be primarily due to donor antibodies activating pulmonary neutrophils in recipients. Recently, a large prospective case controlled clinical study of cardiac surgery patients demonstrated that despite implementation of male donors, a high

T-helper 1 polarization in patients with primary immune thrombocytopenia (ITP) is well documented. However, the genetic contribution to this imbalance remains unclear. To address this question, we selected six candidate single nucleotide polymorphisms within cytokine or cytokine receptor genes for association testing among Caucasian adults. Patients from the United Kingdom Adult ITP Registry were

The treatment of immune thrombocytopenic purpura (ITP) in children is controversial, requiring individualized assessment of the patient and consideration of treatment options. If the platelet count is >10 000/μL and the patient is asymptomatic, a 'watch and wait' strategy is appropriate since most children with ITP will recover completely without pharmacotherapy. If therapy is indicated because of

Platelets are anucleate cells that are crucial mediators of haemostasis. Most immunologists probably don't think about platelets every day, and may even consider these cells to be 'nuisances' in certain in vitro studies. However, it is becoming increasingly clear that platelets have inflammatory functions and can influence both innate and adaptive immune responses. Here, we discuss the mechanisms

In April 2010, a working group sponsored by the National Heart, Lung, and Blood Institute was assembled to identify research strategies to improve our understanding of alloimmunization caused by the transfusion of allogeneic blood components and to evaluate potential approaches to both reduce its occurrence and manage its effects. Significant sequelae of alloimmunization were discussed and identif

PURPOSE OF REVIEW: Immune thrombocytopenia (ITP) is a bleeding disorder in which both antibody and cell-mediated autoimmune responses are directed against an individual's own platelets and/or megakaryocytes, leading to either enhanced platelet destruction and/or reduced platelet production, respectively. The cause of this platelet-specific autoimmunity remains unknown, but there has been a constan

Transfusion-related acute lung injury (TRALI) is a serious complication of transfusion and has been ranked as one of the leading causes of transfusion-related fatalities. Nonetheless, many details of the immunopathogenesis of TRALI, particularly with respect to recipient factors are unknown. We used a murine model of antibody-mediated TRALI in an attempt to understand the role that recipient lymph

BACKGROUND: It is well known that infusion of immunoglobulin (Ig)G-coated cells results in an inhibited antigen-specific humoral immune response compared to the cells themselves, a phenomenon termed antibody-mediated immune suppression (AMIS). Although this AMIS effect has been well described with many different types of cells as well as vaccines and insoluble antigens, the mechanisms behind this

With regards to research animal models related to immune thrombocytopenia (ITP), there is an extensive literature of over 300 publications published since 1959. It appears that many of these models either confirm what has been found in human ITP or, in some instances, are the first to describe a phenomenon related to ITP that is still of relevance today in human medicine. These models will undoubt

While much has been learned about the basic immunology and clinical characteristics of immune thrombocytopenia, many important questions remain with regard to pathogenesis, disease progression, identification of novel therapeutic targets and approaches, and clinical trials that rationalize and optimize use of existing therapies. The answers to these questions are likely to impact our understanding

Although platelets are best known as primary mediators of hemostasis, this function intimately associates them with inflammatory processes, and it has been increasingly recognized that platelets play an active role in both innate and adaptive immunity. For example, platelet adhesive interactions with leukocytes and endothelial cells via P-selectin can lead to several pro-inflammatory events, inclu

Immune thrombocytopenia (ITP) is a bleeding disorder characterized by antibody-opsonized platelets being prematurely destroyed in the spleen, although some patients with ITP may have a cell-mediated form of thrombocytopenia. Although several animal models of ITP have been developed, few mimic primary chronic ITP nor have any shown cell-mediated platelet destruction. To create this type of model, s

In the last 20 years, many publications have shed new light on the complex immunopathogenesis of immune thrombocytopenic purpura. They are associated with 3 interrelated areas of environmental autoimmunity, for example, infectious influences, antigen-presenting cell (APC) function, and T-cell abnormalities, particularly tolerance induction. This article highlights the recent literature and argues

An understanding of how helper T cells are activated to drive blood group immune responses will help to explain the immunogenicity of antigens such as HPA-1a. In this issue of Blood, Anani Sarab and colleagues identify the naturally processed HPA1a peptides recognized by T cells and set the stage for peptide-based therapies in NAIT.(1).

BACKGROUND: Transfusion-related immunomodulation (TRIM) has been correlated with the presence of white cells (WBCs) in blood transfusions, but the role of components such as platelets (PLTs) in mediating TRIM has not been extensively examined. We designed a murine PLT transfusion model to study whether leukoreduced PLTs mediate TRIM effects.STUDY DESIGN AND METHODS: CBA recipient mice were adminis