Hemostatic properties and protein expression profile of therapeutic apheresis plasma treated with amotosalen and ultraviolet A for pathogen inactivation.

Background: The INTERCEPT Blood System (IBS) using amotosalen-HCl and ultraviolet (UV)A inactivates a large spectrum of microbial pathogens and white blood cells in therapeutic plasma. Our aim was to evaluate to what extent IBS modifies the capacity of plasma to generate thrombin and induces qualitative or quantitative modifications of plasma proteins.

Study Design And Methods: Plasma units from four donors were collected by apheresis.

Comparative effectiveness of plasma prepared with amotosalen-UVA pathogen inactivation and conventional plasma for support of liver transplantation.

Background: Liver transplant may require large-volume plasma transfusion with increased risk of transfusion-transmitted infection (TTI). Pathogen inactivation of plasma with amotosalen-UVA offers the potential to mitigate TTI risk.

Study Design And Methods: A retrospective cohort design was used to compare the therapeutic efficacy and key safety outcomes for liver transplants supported with quarantine plasma (Q-FFP [reference]) or amotosalen-UVA plasma (IBS plasma [test]).

Dehydration of blood platelets by zeodration: in vitro characterization and hemostatic properties in vivo.

Background: Platelets (PLTs) are currently stored at room temperature (RT) for 5 to 7 days. So far, there exists no validated method for the preparation and long-term storage of dehydrated PLTs suitable for transfusion after rehydration. In this study, a desiccation process, zeodration, was applied to PLTs.

Proteome changes in platelets after pathogen inactivation--an interlaboratory consensus.

Pathogen inactivation (PI) of platelet concentrates (PCs) reduces the proliferation/replication of a large range of bacteria, viruses, and parasites as well as residual leucocytes. Pathogen-inactivated PCs were evaluated in various clinical trials showing their efficacy and safety. Today, there is some debate over the hemostatic activity of treated PCs as the overall survival of PI platelets seems to be somewhat reduced, and in vitro measurements have identified some alterations in platelet function.

Preserved functional and biochemical characteristics of platelet components prepared with amotosalen and ultraviolet A for pathogen inactivation.

Background: Platelet concentrate (PC) functionality decreases during storage. This is referred to as the storage lesion. Pathogen inactivation may accelerate or induce lesions, potentially accounting for reduced viability.

HLA-DQA2 and HLA-DQB2 genes are specifically expressed in human Langerhans cells and encode a new HLA class II molecule.

The precise role of human epidermal Langerhans cells (LCs) in immune response is highly controversial. While studying the gene expression profile of these cells, we were intrigued to identify the HLA-DQB2 gene as potentially expressed in LCs. Despite a strong evolutionary conservation of their sequences, the concomitant expression of the poorly polymorphic HLA-DQA2/HLA-DQB2 genes, paralogous to the HLA-DQA1/HLA-DQB1 genes, has never been detected in any cell type.

Characterization of megakaryocyte development in the native bone marrow environment.

Differentiation and maturation of megakaryocytes occur in close association with cellular and extracellular components in the bone marrow. Thus, direct examination of these processes in the native environment provides important information regarding the development of megakaryocytes. In this chapter, we present methods applied to mouse bone marrow to (1) examine the ultrastructure of megakaryocytes and their state of maturation in situ in fixed bone marrow sections and (2) study the dynamics of proplatelet formation by real-time observation of fresh bone marrow explants where megakaryocytes have matured in their natural physiological context.

[Universal implementation of pathogen inactivation in labile blood products is a major step towards transfusion safety].

Transfusion of labile blood products (red cell concentrates, platelet concentrates and plasma) is vital in the absence of alternatives. Patients and doctors have always feared infections transmitted by blood, blood components and blood-derived drugs. It is potentially dangerous to delay implementation of pathogen inactivation in labile blood products pending a perfect process.

Hirudin and heparin enable efficient megakaryocyte differentiation of mouse bone marrow progenitors.

Hematopoietic progenitors from murine fetal liver efficiently differentiate in culture into proplatelet-producing megakaryocytes and have proved valuable to study platelet biogenesis. In contrast, megakaryocyte maturation is far less efficient in cultured bone marrow progenitors, which hampers studies in adult animals. It is shown here that addition of hirudin to media containing thrombopoietin and serum yielded a proportion of proplatelet-forming megakaryocytes similar to that in fetal liver cultures (approximately 50%) with well developed extensions and increased the release of platelet particles in the media.

Major contribution of the P2Y₁receptor in purinergic regulation of TNFα-induced vascular inflammation.

Background: Atherosclerosis is an inflammatory disease, and extracellular nucleotides are one of the factors possibly involved in vascular inflammation. The P2Y(1) receptor for adenosine 5'-diphosphate has been shown to be involved in the development of atherosclerosis in apolipoprotein E--deficient mice. Our aim is to determine whether the endothelial P2Y(1) receptor plays a role in leukocyte recruitment during vascular inflammation and characterize underlying mechanisms.

The antithrombotic activity of EP224283, a neutralizable dual factor Xa inhibitor/glycoprotein IIbIIIa antagonist, exceeds that of the coadministered parent compounds.

EP224283 combines in a single molecule idraparinux and tirofiban, which allows obtaining a predictable and sustained antiplatelet effect through the transfer of the pharmacokinetics properties of idraparinux to the anti-αIIbβ3 antagonist. The activity can be instantaneously neutralized by injection of avidin, a specific antidote. We have tested the effects of this new profile anticoagulant in various thrombosis models.

Increased flexibility and liposome-binding capacity of CD1e at endosomal pH.

The plasma membrane proteins CD1a, CD1b and CD1c are expressed by human dendritic cells, the professional antigen-presenting cells of the immune system, and present lipid antigens to T lymphocytes. CD1e belongs to the same family of molecules, but accumulates as a membrane-associated form in the Golgi compartments of immature dendritic cells and as a soluble cleaved form in the lysosomes of mature dendritic cells. In lysosomes, the N-terminal propeptide of CD1e is also cleaved, but the functional consequences of this step are unknown.

Use of additive solutions and pathogen inactivation treatment of platelet components in a regional blood center: impact on patient outcomes and component utilization during a 3-year period.

Background: The Etablissement Français du Sang Alsace (EFS Alsace) successively implemented universal use of platelet additive solutions (PASs) and pathogen inactivation (PI) for platelet components (PCs). To assess the impact of these changes, EFS Alsace evaluated PC use, red blood cell (RBC) component use, and transfusion-related adverse events after implementation of these new technologies.

Study Design And Methods: EFS Alsace prospectively collects data on production, distribution, and response to transfusion of all blood components with greater than 99.

An active hemovigilance program characterizing the safety profile of 7483 transfusions with plasma components prepared with amotosalen and UVA photochemical treatment.

Background: Photochemical pathogen inactivation treatment (PCT) of plasma components with amotosalen and UVA has been implemented in Europe. To establish a postapproval safety database, an active hemovigilance (HV) program utilizing an electronic data capture system (EDCS) was initiated.

Study Design And Methods: The response to transfusion was documented after each PCT-plasma transfusion.

Feasibility study of a screening assay that identifies the abnormal prion protein PrPTSE in plasma: initial results with 20,000 samples.

Background: It is likely that transmission of variant Creutzfeldt-Jakob disease (vCJD) occurs by transfusion and that the candidate infectious agent (PrP(TSE)) is present in small concentrations in the blood of infected donors in the asymptomatic phase of the disease. A new blood screening assay has been developed to detect PrP(TSE) in citrated plasma samples.

Study Design And Methods: Three regional Blood Transfusion Establishments (ETS) in France (ETS Alsace, ETS Bourgogne Franche-Comté, and ETS Pyrénées-Méditerranée) will screen 60,000 plasma samples (20,000 in each ETS) over a time period of approximately 9 to 12 months.

Clopidogrel 150 mg/day to overcome low responsiveness in patients undergoing elective percutaneous coronary intervention: results from the VASP-02 (Vasodilator-Stimulated Phosphoprotein-02) randomized study.

Objectives: We investigated whether maintenance therapy with clopidogrel 150 mg/day produces greater platelet inhibition than the standard 75-mg/day dose and whether the higher maintenance dose increases platelet inhibition in low responders to clopidogrel 75 mg/day.

Background: Patients show interindividual variability in their platelet response to clopidogrel. Low responders could potentially obtain greater clinical benefit from greater doses of clopidogrel.

Intrinsic impaired proplatelet formation and microtubule coil assembly of megakaryocytes in a mouse model of Bernard-Soulier syndrome.

Background: Giant platelets and thrombocytopenia are invariable defects in the Bernard-Soulier syndrome caused by deficiency of the GPIb-V-IX complex, a receptor for von Willebrand factor supporting platelet adhesion to the damaged arterial wall. Various properties of this receptor may be considered potential determinants of the macrothrombocytopenia.

Design And Methods: To explore the underlying mechanisms of the disease, megakaryopoiesis was studied in a mouse model deficient in GPIbbeta.

Transfusion of platelet components prepared with photochemical pathogen inactivation treatment during a Chikungunya virus epidemic in Ile de La Réunion.

Background: During the Chikungunya virus (CHIKV) epidemic on Ile de La Réunion, France, more than 30% of 750,000 inhabitants were infected. Local blood donation was suspended to prevent transfusion-transmitted infection (TT-CHIKV). To sustain the availability of platelet (PLT) components, the Etablissement Français du Sang implemented universal pathogen inactivation (INTERCEPT, Cerus Europe BV) of PLT components (CPAs).

The assembly of CD1e is controlled by an N-terminal propeptide which is processed in endosomal compartments.

CD1e displays unique features in comparison with other CD1 proteins. CD1e accumulates in Golgi compartments of immature dendritic cells and is transported directly to lysosomes, where it is cleaved into a soluble form. In these latter compartments, CD1e participates in the processing of glycolipid antigens.

Use of tandem Biacore-mass spectrometry to identify platelet membrane targets of novel monoclonal antibodies.

The monoclonal antibodies (mAbs) ALMA.17 and ALMA.7 recognize human platelet membrane proteins.

Abnormal megakaryocyte morphology and proplatelet formation in mice with megakaryocyte-restricted MYH9 inactivation.

Mutations in the MYH9 gene encoding nonmuscle myosin IIA lead to macrothrombocytopenia as observed in MYH9-related disorders. We used mice with megakaryocyte-restricted MYH9 inactivation to explore the role of myosin in thrombopoiesis. In situ, bone marrow MYH9Delta megakaryocytes were irregularly shaped, appearing leaky with poorly defined limits.

Reduced atherosclerotic lesions in P2Y1/apolipoprotein E double-knockout mice: the contribution of non-hematopoietic-derived P2Y1 receptors.

Background: The P2Y(1) receptor plays a key role in arterial thrombosis and is widely expressed in many cell types involved in atherosclerosis. The aim of this study was to evaluate its potential involvement in the development of atherosclerotic lesions.

Methods And Results: Apolipoprotein E-deficient (ApoE(-/-)) and P2Y(1)(-/-)/ApoE(-/-) mice were maintained on regular chow for 17 or 30 weeks before analysis of atherosclerotic lesions.