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American Association of Blood Banks (AABB) Annual Meeting – 2018

Understanding the Platelet Status of Plateletpheresis Donors to Optimize Platelet Allocation

A 12-month study was conducted at the Vienna General Hospital Department of Transfusion Medicine starting January, 2016. Microparticle (MP) was measured in platelet-rich plasma (PRP) of 189 unique donors prior to 285 donations to determine their platelet activation status.  Platelet activation status as determined by MP content in donor PRP varies significantly between donors regardless of sex or age and often changes after about 3 months. The activation status of platelets in the donated product is a consequence of platelet activation in the donor, however, the type of cell separator affects the level of residual MP.

 
Why are In Vitro Platelet Characteristics Not Predicting Clinical Outcomes?

In contrast to relative quality control parameters such as P-selectin expression. Microparticle content (MP%) and morphology score reflect the entire history of including donor variability. The data from a clinical study conducted at the Vancouver General Hospital, Canada from 2011 to 2014 enrolled 200 hematology/oncology patients suggest that rather than aiming to predict all outcomes the goal might be to predict the worst outcomes. Platelet transfusions with MP% > 15% or a low morphology score have a high probability of insufficient increase in 24hr CCI in CMV+ AML patients. Thus, a practical approach to improving overall clinical outcomes may be to minimize activated Platelet transfusions for prophylaxis.

 
Could Avoiding Activated Platelets Improve the Sucess Rate of HLA Matched Transfusions

Up to 35% of patients who depend on platelet (PLT) transfusion support become refractory to platelets. Of this refractoriness, 3-5% can be attributed to alloimmunization (primarily HLA antibody mediated) with consecutive 1-hr corrected count increments (CCIs) below 7.5x109/L. According to current clinical practice HLA-positive refractory patients may receive HLA-matched PLTs, however only about 26% of these transfusions result in adequate count increments. This retrospective analysis investigated the possibility that platelet activation status affects the success of HLA matched PLTs and found that selecting non-activated random PLTs for transfusion to HLA-positive patients did not achieve sufficiently high 1-hr CCIs in HLA-positive patients. However, only non-activated HLA matched PLTs restored both 1-hr and 24-hr CCIs in one alloimmunized patient.

 
Activation Status of Pathogen Reduced Platelet Components in Plasma in Comparison with Conventional Plasma Platelet Components
Oral presentation by Dr. Joel Kniep, MD, University of Colorado, Aurora, CO.

Studies suggest that high MP content in platelet components, indicating a high level of platelet activation, may limit the effectiveness of platelet transfusions. Activated platelets may be beneficial to stop active bleeding suggested by work on cryopreserved and cold-stored platelets. Conversely, platelet components with a low MP content (non-activated) may be beneficial for prophylactic platelet transfusion in bone marrow transplant patient population. This study investigated whether pathogen reduction changes the activation status of single donor platelets This study found that PRT and conventional platelet components in plasma showed similar platelet activation distribution based on MP content (MP %).

International Society of Hematology (ISH) 37th World Congress – 2018

Factors influencing platelet refractoriness in hematology-oncology patients — a retrospective analysis of 52 cases
Oral presentation by Dr. Elisabeth Maurer, Founder, LightIntegra Technology

A clinical study conducted at the Vancouver General Hospital, BC, Canada from 2011 to 2014 enrolled 200 hematology oncology patients with informed consent. Retrospective analysis identified 52 refractory patients. Their patient and transfusion data were assessed and compared to non-refractory patients. Retrospective analysis did not reveal alloimmunization, bleeding or patient demographics as major factors associated with platelet refractoriness. However, refractory patients had a higher occurrence of fever, and received more activated platelets than non-refractory patients. Additional studies are needed to determine whether platelet activation status and fever are independent, or if immunomodulatory factors associated with activated platelets contribute to elevated body temperature. Furthermore, the relationship between activated platelets, fever and platelet refractoriness in hematology-oncology patients warrants investigation.

 

Blood Banks Association of New York State (BBANYS) Annual Meeting – 2018

Platelet Activation Rates Vary by Supplier- Potential impact of the method of cell separation

Platelet activation status is used to characterize platelet quality and function. The primary source of platelet activation in donated product is the donor, where inter-donor variability in platelet activation is known to be significant. Platelets that were already activated, or borderline activated, in the donor are more vulnerable to additional activation from stress factors, such as the apheresis collection process. Plasma recirculation combined with elutriation (Amicus) leads to additional stress compared to centrifugation in a conical-shaped chamber (Trima). A retrospective analysis banks of the platelet activation status from various platelet suppliers was conducted to examine the impact of a supplier’s apheresis system on platelet activation.

American Association of Blood Banks (AABB) Annual Meeting – 2017

Screening or Red Blood Cell Concentrates for Microparticle Content as Quality Indicator

The controversy around the quality and clinical impact of aged red blood cell concentrates (RCC) is ongoing. Current studies are limited by the lack of quality measures suitable for routine screening of RCC. Based on evidence that fragments called microparticles (MP) or extracellular vesicles are markers of cellular activation or degradation, this study investigated the utility of MP screening to characterize the effect of RCC production methods and storage. MP Content correlates with measures of hemolysis and other RBC quality indicators and could be implemented as a routine screening tool. Differences in MP content between donors, processes and age could be monitored and used to inform component production decisions.

South Central Association of Blood Banks (SCABB) Annual Meeting – 2017

New studies show reduced platelet utilization and improved patient care using advanced platelet management

A 3-months quality initiative was conducted in a medium-sized US hospital. Platelet management was implemented to avoid transfusion of activated platelets to hematology-oncology patients. We compared the average inpatient platelet usages for the 10 months before the quality initiative (baseline) to the 3 months of the quality initiative. Non-immune platelet refractoriness is a severe condition marked by long, often unsuccessful treatment of hematology-oncology patients at high emotional and financial cost. We found a significant reduction in inpatient platelet use and variability likely due to prevented refractoriness.