Buffy Coat-derived Platelet Concentrates Research Articles

Hepatitis E virus is effectively inactivated in platelet concentrates by ultraviolet C light

As previous investigations have shown, THERAFLEX UV-Platelets, a UVC-based pathogen inactivation (PI) system, is effective against non-enveloped transfusion-relevant viruses such as hepatitis A virus (HAV), which are insensitive to most PI treatments for blood products. This study investigated the PI efficacy of THERAFLEX UV-Platelets against HEV in platelet concentrates (PCs). Buffy coat-derived PCs in additive solution were spiked with cell culture-derived HEV and treated with the THERAFLEX UV-Platelets system using various doses of UVC (0·05, 0·10, 0·15 and 0·20 (standard) J/cm2 ). Titres of infectious virus in pre- and post-treatment samples were determined using a large-volume plating assay to improve the detection limit of the virus assay. THERAFLEX UV-Platelets dose-dependently inactivated HEV in PCs. The standard UVC dose inactivated the virus to below the limit of detection, corresponding to a mean log reduction of greater than 3·5. Our study demonstrates that the THERAFLEX UV-Platelets system effectively inactivates HEV in PCs.

Metabolomics study of platelet concentrates photochemically treated with amotosalen and UVA light for pathogen inactivation

The risk of bacterial contamination and the deterioration of platelet (PLT) quality limit the shelf-life of platelet concentrates (PCs). The INTERCEPT pathogen inactivation system reduces the risk of pathogen transmission by inhibiting nucleic acid replication using a combination of a photo-reactive compound and UVA illumination. The goal of this study was to investigate the effects the INTERCEPT system has on the PLT metabolome and metabolic activity. Paired units of buffy coat-derived PCs were generated using a pool and split strategy (n = 8). The paired PCs were either treated with the INTERCEPT system or left untreated. Samples were collected on Days 1, 2, 4, and 7 of storage. Ultra-performance chromatography coupled with time-of-flight mass spectrometry was used to analyze the extra- and intracellular metabolomes. Constraint-based metabolic modeling was then used to predict the metabolic activity of the stored PLTs. A relatively large number of metabolites in the extracellular environment were depleted during the processing steps of the INTERCEPT system, in particular, metabolites with hydrophobic functional groups, including acylcarnitines and lysophosphatidylcholines. In the intracellular environment, alterations in glucose and glycerophospholipid metabolism and decreased levels of 2-hydroxyglutarate were observed following the INTERCEPT treatment. Untargeted metabolomics analysis revealed residual amotosalen dimers present in the treated PCs. Systems-level analysis of PLT metabolism indicated that the INTERCEPT system does not have a significant impact on the PLT energy metabolism and nutrient utilization. The INTERCEPT system significantly alters the metabolome of the stored PCs without significantly influencing PLT energy metabolism.

Effect of increased agitation speed on pathogen inactivation efficacy and in vitro quality in UVC-treated platelet concentrates.

Pathogen inactivation technologies require continuous development for adjustment to different blood components and products. With Theraflex UV-Platelets, a system using shortwave ultraviolet C (UVC) light (254 nm), efficient mixing of platelet concentrates (PCs) during UVC treatment is essential to ensure homogeneous illumination of the blood components. In this study, we investigated the impact of increasing the agitation speed during UVC treatment on pathogen inactivation capacity and platelet quality. The pathogen inactivation efficacy of UVC treatment was evaluated at two agitation speeds (110 vs. 180 rpm) using four different transfusion-relevant bacteria strains and three model viruses. Using a pool-and-split design, the in vitro quality of buffy coat-derived PCs stored in SSP+ additive solution for up to 7 days was assessed in UVC-treated PCs agitated at either 110 rpm (standard speed) or 180 rpm (increased speed) and in untreated controls. The higher agitation speed improved bacterial inactivation but did not influence viral inactivation. Metabolic activity (glucose consumption and lactate accumulation) in UVC-treated platelets was slightly higher than in untreated controls. Increases in parameters such as CD62P expression and annexin A5 binding indicated moderate activation of UVC-treated platelets. Quality variables for UVC-treated platelets agitated at standard vs. increased agitation speed were comparable. The mixing rate during illumination may be a process parameter for further development of UVC-based pathogen inactivation procedures for PLT concentrates.

The efficacy of the ultraviolet C pathogen inactivation system in the reduction of Babesia divergens in pooled buffy coat platelets

Babesia spp. is an intraerythrocytic parasite that causes human babesiosis and its transmission by transfusion has been extensively demonstrated. The aim of this study was to ascertain the efficacy of an ultraviolet C (UVC)-based pathogen inactivation system in the reduction of Babesia divergens-infected platelet (PLT) concentrates and to determine the parasite's ability to survive in PLT concentrates stored under blood bank conditions. This study was conducted using in vitro cultures of B. divergens. The detection limit of the culture assay was established and, subsequently, 15 buffy coat-derived PLT concentrates (BC-PCs) were inoculated with 10(7) B. divergens-infected red blood cells. Infected BC-PCs were irradiated with 0.2 J/cm(2) UVC light using the THERAFLEX UV-Platelets method (Macopharma). Viability and parasite growth were evaluated before and after inactivation. Culture growth kinetics were monitored by DNA incorporation of [(3) H]thymidine. The ability of B. divergens to survive in PLT concentrates was also analyzed. The limit of detection in cultures was established at 0.1 × 10(-6) % parasites. The THERAFLEX UV-Platelets system inactivated B. divergens to below the limit of detection in 12 of 15 BC-PCs (log reduction, >6.0) and to the limit of detection (log reduction, 5.0) in three of 15. It was also demonstrated that B. divergens remains viable in BC-PCs stored up to 7 days. Since B. divergens can survive in PLT concentrates and given the performance of UVC, this system could be considered as an alternative to prevent B. divergens and other Babesia species from being transmitted through PLT transfusions.

Pathogen reduction treatment alters the immunomodulatory capacity of buffy coat–derived platelet concentrates

Storage of platelet concentrates (PCs) after Mirasol pathogen reduction technology (PRT) treatment changes platelet (PLT) surface marker expression and secretion of immunomodulatory factors. Given that PLTs are known to participate in immune function, PRT may alter the way PLTs interact with the immune cells of a recipient upon transfusion. As such, the aim of this study was to assess the effects of PRT treatment on the functional ability of PLTs to interact with peripheral blood mononuclear cells (PBMNCs). Buffy coat-derived PCs were pooled and split to obtain matched pairs. One unit was treated using the Mirasol PRT system, while the control PC remained untreated. After 5 days of storage, either the PLTs or the PLT supernatants from the PCs were cocultured with PBMNCs, with or without lipopolysaccharide (LPS). The immunomodulatory factors secreted into culture medium after coculture were examined. PRT-treated PLTs and PLT supernatant significantly increased the interleukin (IL)-8 concentration, which was manifested only in the presence of LPS. Conversely, PRT-treated PLTs secreted less soluble P-selectin (sCD62P) upon coculture with PBMNCs. PRT-treatment induced differential secretion of IL-8 and sCD62P during coculture, which may be attributed to either bioactive substances present in PLT supernatant or as a result of cell-cell interactions.

Platelets from platelet-rich-plasma versus buffy-coat-derived platelets: what is the difference?

Platelets from platelet-rich-plasma versus buffy-coat-derived platelets: what is the difference?

Leukoreduced buffy coat–derived platelet concentrates photochemically treated with amotosalen HCl and ultraviolet A light stored up to 7 days: assessment of hemostatic function under flow conditions

Amotosalen plus ultraviolet A light photochemical treatment (PCT) inactivates high titers of bacteria, and other pathogens, in platelet concentrates (PCs) potentially allowing the storage of platelets (PLTs) for up to 7 days. Adhesion and aggregation of PLTs to injured vascular surfaces are critical aspects of PLT hemostatic function. Two ABO-identical leukoreduced buffy coat-derived PCs in additive solution were mixed and divided: one-half underwent PCT (PCT-PCs) and the other was kept as a control (C-PCs); both were stored under standard conditions. The total number of paired PCs studied was nine. Samples were taken on Day 1 (before PCT) and after 5 and 7 days of storage. The adhesion and aggregation capacities were evaluated under flow conditions in a ex vivo perfusion model. Compared to control, PCT resulted in a decrease in PLT count of 6.5 percent (p = 0.004) and 10.2 percent (p = 0.008) after 5 and 7 days' storage, respectively (n = 9). PLT interaction with subendothelium was mainly in form of adhesion. The surface covered by PCT PLTs on Day 1 was 26.0 +/- 4.2 percent (mean +/- SEM). On Day 5, PCT-PCs showed a covered surface of 20.9 +/- 2.2 percent, and the C-PCs, 20.6 +/- 1.6 percent. After 7 days, PCT-PCs produced a nonsignificant higher PLT deposition compared to control (27.1 +/- 2.9% vs. 21.2 +/- 2.8%, p = 0.06). PCT of PCs and storage up to 7 days was associated with a 10.2 percent decrease in PLT count due to processing losses compared to C-PC. PLT adhesive and aggregating capacities under flow conditions of PCT-PCs were similar to C-PCs and remained well preserved for up to 7 days of storage.

Soluble glycoprotein V as a quality marker of platelet concentrates stressed by transportation

Despite ongoing improvements in storage conditions for platelet concentrates (PCs) for clinical use, leukoreduced platelets (PLTs) undergo subtle changes that are partly due to PLT activation. As PLTs are activated, the expression of P-selectin (CD62P) increases, and soluble glycoprotein V (sGPV) is released. GPV, part of the GPIbIXV complex, has been suggested as a marker of PLT activation. An array of assays, used for quality control of PCs, was performed and the results were compared. The tests included PLT count, swirling, mean PLT volume, extent of shape change (ESC), hypotonic shock response (HSR), CD62P, lysosomal membrane protein (CD63), sGPV, and the metabolic tests (pH, pO(2), pCO(2), lactate, glucose). The performance of the assays was evaluated during the storage period by comparing buffy coat-derived PCs (24 PCs of 4 units) stored on flatbed agitator or stressed twice by overnight transportation. The repeatability of all tests was good. ESC and HSR correlated with each other (r = 0.559). Importantly, there were also associations between sGPV and ESC (r = -0.564) and HSR (r = -0.389). The correlations of sGPV with lactate and glucose concentrations and with expression of CD62P and CD63 were also good. No significant changes were induced by two overnight transportations. sGPV might be applicable for statistical process control of the quality of PCs, in addition to metabolic tests. It may also be helpful in analyzing potential improvements in blood component processing. Repeat transportation of PCs may cause minimal changes on PLT in vitro properties, if any.

Current methods of assessing platelet function: relevance to transfusion medicine

Current methods of assessing platelet function: relevance to transfusion medicine

White Blood Cell Subsets in Buffy Coat-Derived Platelet Concentrates: The Effect of Pre- and Poststorage Filtration

Background and Objectives: Our objective was to study the effect of storage time on the filtration of platelet concentrates (PCs). We compared the total number of white blood cells (WBC), as well as the distribution of WBC subsets, in units filtered before and after storage. Materials and Methods: Buffy coat-derived PCs were filtered either fresh or after 5 days of storage, and total WBC were enumerated by flow cytometry. WBC subsets were analyzed by flow cytometry with three-color fluorescence. Results: The total number of white cells before filtration was significantly higher in fresh units compared with stored units, whereas in postfiltration samples the number of white cells was significantly lower in the fresh compared with the stored units. Although absolute numbers were significantly reduced, filtration also induced significant changes in the proportions of subsets in both fresh and stored units; the percentage of T cells was decreased, whereas the percentage of B cells and monocytes was increased after filtration. Conclusion: Our results suggest that prestorage WBC filtration of platelet concentrates is superior in reducing the absolute numbers of WBC. However, both pre- and poststorage WBC filtration significantly affect the proportions of WBC in the final product, decreasing the number of T cells while apparently increasing the proportion of MHC class II-positive cell populations.

White Blood Cell Subsets in Buffy Coat-Derived Platelet Concentrates: The Effect of Pre- and Poststorage Filtration

Background and Objectives: Our objective was to study the effect of storage time on the filtration of platelet concentrates (PCs). We compared the total number of white blood cells (WBC), as well as the distribution of WBC subsets, in units filtered before and after storage. Materials and Methods: Buffy coat-derived PCs were filtered either fresh or after 5 days of storage, and total WBC were enumerated by flow cytometry. WBC subsets were analyzed by flow cytometry with three-color fluorescence. Results: The total number of white cells before filtration was significantly higher in fresh units compared with stored units, whereas in postfiltration samples the number of white cells was significantly lower in the fresh compared with the stored units. Although absolute numbers were significantly reduced, filtration also induced significant changes in the proportions of subsets in both fresh and stored units; the percentage of T cells was decreased, whereas the percentage of B cells and monocytes was increased after filtration. Conclusion: Our results suggest that prestorage WBC filtration of platelet concentrates is superior in reducing the absolute numbers of WBC. However, both pre- and poststorage WBC filtration significantly affect the proportions of WBC in the final product, decreasing the number of T cells while apparently increasing the proportion of MHC class II-positive cell populations.

A system for the supply of platelets suspended in a storage medium including buffy-coat-derived platelet concentrates in combination with ?split? apheresis platelets

Our objective was to create a system for the supply of platelet concentrates (PCs) based on leukocyte-filtered PCs suspended in a storage medium (PAS-II) including: (1) pooled buffy-coat-derived (BC) PCs and (2) “split” apheresis PCs. The same standards were intended for the two preparations with regard to composition and blood cell counts. In preliminary studies, similar in vitro data were found for leukocyte-filtered and non-filtered reference BC PCs. Slightly inferior in vitro results than for BC PCs restricted the shelf-life of apheresis PCs to 5 days compared to 7 days for BC PCs. With the present platelet supply system in use as a routine service for one year, the experience was very satisfactory, meeting the demands for PCs very efficiently and resulting in a low out-dating rate (5%).

A system for the supply of platelets suspended in a storage medium including buffy-coat-derived platelet concentrates in combination with “split” apheresis platelets

Our objective was to create a system for the supply of platelet concentrates (PCs) based on leukocyte-filtered PCs suspended in a storage medium (PAS-II) including: (1) pooled buffy-coat-derived (BC) PCs and (2) “split” apheresis PCs. The same standards were intended for the two preparations with regard to composition and blood cell counts. In preliminary studies, similar in vitro data were found for leukocyte-filtered and non-filtered reference BC PCs. Slightly inferior in vitro results than for BC PCs restricted the shelf-life of apheresis PCs to 5 days compared to 7 days for BC PCs. With the present platelet supply system in use as a routine service for one year, the experience was very satisfactory, meeting the demands for PCs very efficiently and resulting in a low out-dating rate (5%).