Apheresis Platelet Concentrates Research Articles

Investigation of the Release of Growth Factors from Apheresis Platelet Concentrate (APC) Loaded Three Layered Composite Nanofiber Surface

In this study, a nanofiber surface loaded with apheresis platelet concentrate (APC) was produced for the first time to develop a bioactive wound dressing design. Nanofiber surface (n=5) consisting of polyurethane polymer outer layer, polyvinyl alcohol polymer middle layer, and polycaprolactone polymer matrix inner layer were produced via the electrospinning method. The surface morphologies of the produced nanofiber surfaces were examined by scanning electron microscopy. Quantitative analyzes of growth factors released from the APC-loaded composite nanofiber surfaces into phosphate-buffered saline at certain time intervals were performed with the ELISA. When the release amounts between bFGF, EGF, and PDGF-AA groups were compared, a significant difference was found in all periods (p0.05), but there was a significant difference between the EGF and PDGF-AA growth factors (p

Human platelet concentrates treated with microbicidal 405 nm light retain hemostasis activity

Chemical and UV light-based pathogen reduction technologies are currently in use for human platelet concentrates (PCs) to enhance safety from transfusion-transmitted infections. Relative to UV light, 405 nm violet-blue light in the visible spectrum is known to be less harmful. Hence, in this report for the first time, we have assessed the global hemostasis activity of PCs stored in plasma and the activities of six plasma coagulation factors (CFs) as a measure of in vitro hemostatic activity following exposure to the microbicidal 405 nm light. Apheresis PC samples collected from each screened human donor (n = 22) were used for testing of PCs and platelet poor plasma (PPP). Both PCs and PPPs were treated for 5 h with 405 nm light to achieve a previously established microbicidal light dose of 270 J/cm2. Activated partial thromboplastin time and prothrombin time-based potency assays using a coagulation analyzer and hemostatic capacity via Thromboelastography were analyzed. Thromboelastography analysis of the light-treated PCs and plasma present in the PCs showed little difference between the treated and untreated samples. Further, plasma present in the PCs during the light treatment demonstrated a better stability in potency assays for several coagulation factors compared to the plasma alone prepared from PCs first and subjected to the light treatment separately. Overall, PCs stored in plasma treated with 405 nm violet-blue light retain activity for hemostasis.

Comparative analysis of the quality of platelet concentrates produced by apheresis procedures, platelet rich plasma, and buffy coat.

Platelet concentrates (PCs) could be prepared using either whole-blood processes or apheresis instruments. During collection, processing and storage, some biochemical and functional changes occur, which may result in quality reduction. Quality evaluation of PCs may be helpful for the precise control of platelet (PLT) inventory to reduce the risk of refractoriness and adverse effects caused by platelet transfusion. The study was aimed to evaluate the quality of PCs which were produced by five processes: apheresis (AP) procedures (using three different cell separators: Amicus, Trima Accel and MCS+ instruments), platelet rich plasma (PRP), and buffy coat (BC). A total of 100 PCs (20 of each group) were assessed in respect of routine quality control, morphology, size distribution, destroyed and activated platelets, and production of platelet-derived microparticles (PMPs). All PCs have satisfied the recommended quality of volume, platelet count, residual WBC count, residual RBC count, pH, and sterility according to the Chinese Technical Manual. There was no difference among the 5 groups in morphology and size of PLT and PMPs. Dynamic light scattering test showed that apheresis PCs showed peaks around 10-20 nm, but not whole blood-derived PCs. PCs prepared by Amicus had the relatively high percentage of destroyed platelet, activated platelets and PMPs than other groups. The data suggested high heterogeneity of PMPs, destroyed and activated platelets in PCs produced by different processes, which might be helpful to manage the platelet inventory for targeted use.

Platelet Apheresis: Experience of the blood transfusion center of Avicenne military hospital in Marrakesh

Apheresis platelet concentrates (APC) are platelet suspensions obtained by apheresis from a cell separator. These techniques, which appeared a little more than 20 years ago, are currently the best way to obtain platelets in large quantities from a single donor. These separators, whether discontinuous or continuous flow, perform extracorporeal circulation from anticoagulated blood, which allows the collection of platelets, returning to the donor his red blood cells and a more or less important part of his plasma. The procedures used are all automated and often adaptable to the donor's parameters. Apheresis platelet concentrates are single-donor products and therefore limit the transfusion risks compared to standard platelet concentrate mixtures, which are derived from five to six donors on average. The objective of our work is to study platelet donations by apheresis technique, their advantage, indication, and description of the equipment used, during a period of 3 years, from July 2017 until July 2020. And during this period, 29 apheresis procedures were performed by HAEMONETICS' MCS+. The clinical hematology department is the first applicant of APC where acute leukemia and non-Hodgkin's lymphoma are the most treated pathologies by this substitution.

Bioactive lipids as biomarkers of adverse reactions associated with apheresis platelet concentrate transfusion.

Platelet concentrate (PC) transfusion seeks to provide haemostasis in patients presenting severe central thrombocytopenia or severe bleeding. PCs may induce adverse reactions (AR) that can occasionally be severe (SAR). PCs contain active biomolecules such as cytokines and lipid mediators. The processing and storage of PCs creates so-called structural and biochemical storage lesions that accumulate when blood products reach their shelf life. We sought to investigate lipid mediators as bioactive molecules of interest during storage and review associations with adverse reactions post-transfusion. To facilitate understanding, we focused on single donor apheresis (SDA) PCs with approximately 31.8% of PCs being delivered in our setting. Indeed, pooled PCs are the most widely transfused products, but the study of a single donor lipid mediator is easier to interpret. We are investigating key lipid mediators involved in AR. Adverse reactions were closely monitored in accordance with current national and regional haemovigilance protocols. Residual PCs were analysed post-transfusion in a series of observations, both with and without severe reactions in recipients. A decrease in the lysophosphatidylcholine species to produce the lysophosphatidic acid species has been observed during storage and in the case of AR. Lysophosphatidic acid increased with primarily platelet-inhibitor lipids. Anti-inflammatory platelet-induced inhibition lipids were weakly expressed in cases of severe adverse reactions. We therefore propose that a decrease in lysophosphatidylcholine and an increase in lysophosphatidic acid can prospectively predict serious adverse transfusion reactions.

Variation in activation marker expression within the platelet population – a new parameter for evaluation of platelet flow cytometry data

In flow cytometry, individual cells are investigated. Platelet activation is normally reported in form of percentage of platelets expressing the marker (positive platelets) and/or mean/median fluorescence intensity (MFI) for the entire analyzed population. None of these take into account the variance of the marker expression between individual platelets. This can be obtained as data on coefficient of variation (CV). This study explores if CV provides additional information regarding platelet function. Samples from platelet concentrates (PCs) prepared by apheresis- (n = 13) and interim platelet unit (IPU) technique (n = 26) and stored for 6–7 days were included and compared. Spontaneous- and agonist-induced expression of activation markers (fibrinogen binding and exposure of P-selectin, LAMP-1, and CD63) was investigated as percentage positive platelets, MFI and CV. Spontaneous expression of P-selectin as percentage positive platelets and MFI was higher for IPU PCs than apheresis PCs, which in contrast had higher agonist-induced activation. CV for spontaneous fibrinogen binding and P-selectin exposure was larger for apheresis PCs, while IPU PCs generally had larger CV for P-selectin, LAMP-1, and CD63 after agonist stimulation. Our findings show that CV adds additional information when assessing platelet activation by providing data on the variation in activation responses within the platelet population.

In vitro characteristics of cryopreserved platelet concentrates reconstituted by fresh frozen or lyophilized plasma.

Six percent dimethyl sulfoxide (DMSO) cryopreservation of platelet concentrates (PCs) allow longer storage of PCs but require time-consuming post-thaw washing. An alternative process based on removing supernatant before freezing has been implemented in several centres worldwide. We assessed the in vitro characteristics of cryopreserved PCs (CPPs) prepared according to this latest process using either French lyophilized plasma (FLyP) or fresh frozen plasma (FFP) for reconstitution. FLyP provides additional benefits to the process due to its logistical constraints and quick availability. Apheresis PCs (n=16) and buffy coat PCs (n=16) were cryopreserved in 6% DMSO. After storage at -80°C, PCs were thawed and reconstituted with FFP or FLyP. Volume, residual leukocytes, total platelet counts (TPCs), post-thaw recovery, biochemical parameters, and DMSO concentration were assessed. Platelet functions were analysed by swirling index, viscoelastometric assay and CD62P quantification. After reconstitution, TPC was above 2.1011/CPs; recovery was 78±14% with no significant difference between FFP and FLyP. Glucose and lactate levels were not different between plasmas, whereas FLyP-CPPs exhibited a significant increase in LDH and significantly lower pH. Residual DMSO was 8±4G/L. Functional analysis revealed significant differences between FFP and FLyP-CPPs, with lower clot firmness and increased clot initiation. Activation of platelets was not higher in FLyP-CPPs. Preparing CPPs according to this "new" process fulfilled the French legal criteria regardless of the type of plasma. Differences highlighted between FFP-CPPs and FLyP-CPPs were unlikely to be of clinical relevance.

Haemostatic profile of riboflavin-treated apheresis platelet concentrates.

The haemostatic activity of platelet concentrates (PCs) treated with pathogen reduction technology (PRT) remains a subject of debate. Our aim was to investigate the effect of Mirasol PRT on the haemostatic properties of PCs stored in plasma. Untreated and Mirasol-treated platelets stored in plasma and derived from ten split double-dose apheresis PCs were evaluated in vitro on days 1, 3 and 5 post collection for functionality, microparticle procoagulation activity (MPA), endogenous thrombin potential (ETP), and haemostatic profile using rotational thromboelastometry (ROTEM). P-selectin expression was significantly higher in Mirasol-treated platelets compared with untreated counterparts on days 3 and 5 (p=0.003 and p=0.002, respectively). Clot strength, as shown by EXTEM maximum clot firmness (MCF), was significantly lower in the Mirasol-treated platelets at all time points (days 1, 3, 5) than in untreated platelets (p=0.009, p<0.001, p<0.001, respectively). There was a considerable increase in MPA over time (p<0.001) and this was significantly higher in the Mirasol-treated platelets on day 5 (p=0.015). A notable acceleration of decrease in ETP values was observed for Mirasol-treated PCs over time (p<0.001), with significant differences between PRT-treated and untreated PCs on days 3 and 5 (p=0.038 and p=0.019, respectively). Clot strength attenuation was significantly associated with pH reduction (p<0.001, Spearman's rho: 0.84), increased microparticle procoagulant activity (p<0.001, Spearman's rho: -0.75), and with decreased ETP (p<0.032, Spearman's rho: 0.41). Increased platelet activation induced by PRT treatment leads to a decrease in in vitro haemostatic capacity as seen by reduced clot strength and thrombin generation capacity over time. The clinical relevance of this needs to be investigated.

Abstract 158: Bioactive Lipids As Biomarkers Of Severe Adverse Reaction Associated With Apheresis Platelet Concentrate Transfusion

Blood transfusion is a life-saving procedure in which whole blood, or blood components are provided to a patient. Platelet concentrates (PC) may sometimes induce adverse reactions, that are occasionally severe. PC comprise active biomolecules such as cytokines and lipid mediators. Platelet storage lesions are structural and biochemical changes in PC and vary in collection and processing conditions. We investigated lipid mediators as bioactive molecules along storage conditions and in adverse reactions after transfusion. The PC left over were analysed after transfusion, classified with/out severe reaction. Our data presented a decrease of lysophosphatidylcholine species to produce lysophosphatidic acid species. This balance could lead and be correlated with complication symptoms, as other lipids. Lysophosphatidic acid increased with primarily platelet-inhibitor-lipids when single donor apheresis platelet upon storage. Anti-inflammatory and platelet-induced-inhibition lipids were weakly expressed in case of severe adverse reaction. Thus, a decrease in lysophosphatidylcholine and an increase in lysophosphatidic acid could be reliable predictors of serious adverse transfusion reactions transfusion. These data highlighted the importance of PC manufacturing and storage processing, not only to maximize clinical efficacy but also to minimize adverse reactions.

Platelet Transfusion-Insights from Current Practice to Future Development.

Since the late sixties, therapeutic or prophylactic platelet transfusion has been used to relieve hemorrhagic complications of patients with, e.g., thrombocytopenia, platelet dysfunction, and injuries, and is an essential part of the supportive care in high dose chemotherapy. Current and upcoming advances will significantly affect present standards. We focus on specific issues, including the comparison of buffy-coat (BPC) and apheresis platelet concentrates (APC); plasma additive solutions (PAS); further measures for improvement of platelet storage quality; pathogen inactivation; and cold storage of platelets. The objective of this article is to give insights from current practice to future development on platelet transfusion, focusing on these selected issues, which have a potentially major impact on forthcoming guidelines.

Frequency and clinical characteristics of allergic transfusion reactions in children

Allergic transfusion reactions (ATRs)are a common form of acute transfusion reaction. It was aimed to determine the clinical characteristics and frequency of ATRs in children. This study included children who were transfused with red cell concentrate (RCC), fresh-frozen plasma (FFP), platelet concentrates(PC), apheresis granulocyte, and cryoprecipitate.The patients’ sociodemographic characteristics, the blood product that caused the reaction, the type and timing of the reaction, the patient’s age at time of reaction and their diagnosis, follow-up period, and clinical data were recorded. A total of 89703 bags of blood products were transfused to 4193 children.Two hundred eleven acute transfusion-related reactions occurred in 157 (3.74%) patients.Of these, 125 reactions (59%) were allergic. ATR occurred in 125 of 89703 infusions (0.14%).The median age of patients was 9.99 years (IQR:4.67-14.38) and ATRs occurred at a median of 30 minutes into the transfusion. Eighteen (18%) of the patients also had a history of drug reaction.When the blood products that caused ATRs were examined, 43(34.5%) occurred with apheresis and single-donor PC, 37(29.6%) with FFP, 32 (25.6%) with RCC, 10(8%) with pooled PC, 2(1.6%) with cryoprecipitate, 1(0.8%) with apheresis granulocyte.Ninety-nine(79%) of the reactions were minor allergic reactions and 26(21%) were anaphylaxis.Compared to minor allergic reactions, the proportion of PCs was statistically higher in anaphylaxis(p=0.02). Patients receiving PC should be monitored more carefully during the first half hour of transfusion. In addition, approximately one-fifth of the patients who developed ATR also had a history of drug reaction. Patients with previous reactions to drugs may be more likely to have ATR.

Does time of CCI measurement affect the evaluation of platelet transfusion effectiveness?

The measurement of corrected count increment at 1-h post-transfusion (CCI-1 h) of platelet concentrate (PC) transfusion is recommended, but in the revised Japanese Guideline (2017) it was changed to “after 10-min to 1-h”, following the revision of the guidelines from Western countries. Here, we aimed to investigate on the feasibility to apply the CCI measured at 10-min or 30-min post-transfusion as the surrogate of CCI-1 h. Peripheral blood was collected at 10-min, 30-min and 1-h post-transfusion of PC and the effectiveness of the transfusion was analyzed based on the CCI. In the period from December 2017 to February 2020, 8 patients, who received multiple PC transfusion (total 208) at our institution, were analyzed. We performed the univariate analyses to examine the relationship between CCI value and the categorical variables, p-value <0.1 was obtained for gender (p = 2.91 × 10−19), fever after transfusion (p = 0.0163). The qualitative variables, namely measurement time (p = 0.0553), also showed p-value <0.1. Using these factors as covariates in the mixed effect model, we found that the measurement time (p = 0.0007) had a significant effect on the CCI value when looking at fixed effects. Although there is a tendency for decreased CCI values with time progression, the slope of the change in the mixed model was -0.00307, indicating that the CCI difference among the 3 measurements was small. Here we provide evidence that CCI measured at 10-min and 30-min post-transfusion give results comparable to those measured at 1-h post-transfusion, under the Japanese practice of platelet transfusion, which relies on 100 % single-donor apheresis PC, and ABO-identical whenever possible.

Buffy coat pooled platelet concentrate: A new age platelet component.

BACKGROUND:Buffy coat pooled platelet concentrate (BCPP) is a new blood component mainly used in Europe, which has good attributes of both random donor platelets and apheresis platelets in terms of high platelet count, leukoreduced and available in emergency. We planned this study to compare quality parameters and biochemical activation markers among buffy coat pooled platelets and apheresis platelet concentrate (AP-PC) to establish the quality and safety of this new blood component during storage.MATERIALS AND METHODS:Three different preparations of BCPP were prepared: Nonleukoreduced (BCPP Part A), leukoreduced (BCPP Part B), and leukoreduced with platelet additive solution (PAS) (BCPP Part C) using a pool of 15 ABO-matched, nonreactive buffy-coats in each experiment to avoid any donor-related variations. Ten such experiments were done. Each BCPP was equivalent to 5 buffy coat units. Ten apheresis platelets were taken as control. Serial samplings were done on day 0, 3, and 5 of collection and were assessed for: volume, platelet count, white blood cell count, swirling, pH, sterility, glucose, lactate, soluble p-selectin, Interleukin (IL)-6, IL-1 β, and tumor necrosis factor alpha (TNF-α).RESULTS:BCPP Part C (leukoreduced with PAS) maintained the best quality parameters in terms of maintenance of pH, least lactate accumulation, least sP-selectin levels, and least accumulation of inflammatory mediators (IL-6, IL-1 β, and TNF-α) than the other groups >BCPP part B >AP-PC and >BCPP Part A. On day 5 of storage pH for BCPP Part A, Part B, Part C, and AP-PC was: 6.33, 6.42, 6.64, and 6.29, respectively, and soluble p-selectin (ng/ml) was 201 ± 22, 186 ± 11, 149 ± 18, 200 ± 23, respectively. BCPP Part B and AP-PC had comparable quality parameters and activation markers.CONCLUSIONS:Buffy coat pooled platelet has comparable and even better-quality control parameters (especially leukofiltered with PAS) than conventional platelet preparation and is a good alternative for meeting platelet transfusion requirements of critical patients during emergency hours in resource-constraint setting.

COVID-19 pandemisinin Türkiye'deki kan kaynak ve ihtiyacı üzerine etkisi

INTRODUCTION: Coronovirus disease(COVID-19)rapidly spread worldwide after its first report in December 2019,in China.This spread drastically reduced the number of blood donations,thereby creating a shortage at blood banks in the whole world.Turkish Red Crescent(TRC) is the only legal authority that organizes collection,production,storage and distribution of blood and blood components in Turkey.Only in case of emergencyTRC gives permanent permission to hospitals;for collecting blood and producing its components through their own transfusion centers.This report describes how theCOVID-19 impacted blood supplies ofTRC and hospital demands in Turkey with an aim to improve the management of blood supply and demand during theCOVID-19 and future pandemics. METHODS: A cross-sectional study was conducted for a period of nine months;from November 1,2019 to July 31,2020.Data were retrospectively obtained from donor attendance and blood inventory records ofTRC and included;1)the number of donated units of apheresis platelet concentrates(APC) and blood toTRC,2)the number of units ofAPC and erythrocyte suspensions(ES) supplied by the hospitals themselves,3)the number of units of APC andES supplied to hospitals by TRC(APCHandESH).The periods before(first period) and after(third period)arrival of COVID-19 to Turkey are compared. RESULTS: An increase of 52%in the number of APCdonations,but a decrease of 22% in the number of blood donations(NBD) were detected in the third period compared to the first one.Mean APCH were 7081±550 and5121±255 units in the first and third periods,respectively.The mean ESH in the first period was 873±326 units,while it was3694±3143 units in the third period. DISCUSSION AND CONCLUSION: It is obvious that we have learnt many lessons from theCOVID-19 pandemic,like how to face challenges in maintaining the balance between blood demandandblood supply.Utilizing media to encourage donors and implementation of PatientBloodManagement on national and institutional levels may be some some of the key components of a comprehensive strategy.The collaboration ofMinistry of Health,TRC and hospitalswassuccessful in securing a balance between blood supply and demand in Turkey,which COVID-19 pandemic impacted significantly.

Blood transfusion service in Poland in 2019

Background: In this study we evaluated the basic aspects of the activity of the Polish Blood Transfusion Service (hereinafter referred to as Centers) in 2019. Materials and methods: Retrospective analysis of the 2019-data supplied by the Centers. Results: In 2019, blood and blood components were collected in 21 Polish Centers and 129 local collection sites as well as during 13 048 mobile collections. The overall number of blood donors was estimated at 590 893, the majority of which were non-remunerated donors (590 280 — including 40 738 responders to donation appeals), as well as 57 remunerated donors and 556 autologous donors. Most frequent were whole blood collections (1 202 079) and least frequent — granulocyte concentrate collections (94) and RBCs collections by apheresis (48 donations). Whole blood was collected mostly in local collection sites (45.25%), in Centers (28.75%) and mobile collection sites (26%). Most frequently prepared blood components were RBCs — 1 180 333 units) and fresh frozen plasma (FFP — 1 344 092 units, 21.42% dedicated for clinical use). Platelet concentrates (PCs) collected by apheresis amounted to 53 379 units and 81 905 were whole blood-derived. Additional processing methods (leukocyte depletion, irradiation) were more frequently applied to PCs (43.34% leukocyte-depleted, 0.04% irradiated, 54.63% both leukocyte-depleted and irradiated) than to RBCs (18.71% leukocyte-depleted, 0.06% irradiated, 9.17% both leukocytedepleted and irradiated). Pathogen reduction technologies were applied to 20.76% of FFP units issued for clinical use (transfusion) and 11.87% of PCs. In 2019 — for a variety of reasons — 14 013 units of whole blood, 32 798 units of RBCs, 49 285 units of FFP, 1334 units of cryoprecipitate, 4778 units of pooled PCs and 1279 of apheresis PCs were wasted. Conclusions: Our study data may be considered as starting point for assessment of the tendencies observed in the Polish blood transfusion service and may serve practical-benchmarking with benefit to the transfusion community as a whole.

Residual red cells in blood components: A multisite study of fully automated enumeration using a hematology analyzer.

BackgroundManufacture of platelet concentrates (PCs) and plasma may fail to remove all residual red blood cells (rRBCs). Measuring rRBCs for compliance to guidelines has proven challenging, leading to an absence of a consensus methodology. Sysmex hematology analyzers with the Blood Bank mode (BB mode) analysis option offer the potential for automated rRBC counting. We therefore performed a two‐site appraisal of the system.Study Design and MethodsPerformance characteristics were determined using platelet and plasma samples spiked with RBCs. Sample stability (n = 47) and the impact of sample type were also assessed. Components (platelets, n = 1474; plasma, n = 77) prepared using different routine manufacturing methods were tested to assess variation in rRBC concentration.ResultsLinearity studies up to 19 000 RBCs/μL demonstrated good correlation between expected and observed results (R2 ≥ 0.9731), and flow cytometric results also correlated well with BB mode (R2 = 0.9400). Precision analysis gave a limit of quantitation of 6 to 7 RBCs/μL, and carryover was 0.03%. Ethylenediaminetetraacetic acid and plain tube results were not significantly different (P ≥ 0.10), and samples were stable up to 24 hours. Apheresis PCs produced at two sites had lower rRBC concentrations (medians, 17 and 13 RBCs/μL) than those produced with the buffy coat method either manually (median, 681 RBCs/μL) or with the automated Terumo Automated Centrifuge and Separator Integration process (median, 81 RBCs/μL). All PCs failing visual inspection as having RBCs ≥4000 RBCs/μL were also detected by the BB mode.ConclusionThe BB mode had acceptable performance characteristics and has the potential for integration into a fully automated process control system for rRBC enumeration in plasma and PCs.

Digital droplet polymerase chain reaction to monitor ultraviolet C treatment of single-donor and buffy coat platelet units.

UVC illumination of agitated platelet concentrates (PCs) inactivates pathogens and white blood cells by modifications of their nucleic acids. Related effects on mitochondrial DNA (mtDNA) in platelets serve as a basis for an efficient monitoring suited for routine quality control (QC) of this purely physical pathogen reduction technology. Samples from PCs (n = 530) were tested with an established LightCycler PCR (LC PCR) for QC of the UVC procedure. RNR2 and TRNK/ATP8 genes were sequenced in the PCs (n = 21) with out-of-specification results in the LC PCR. A digital droplet PCR (ddPCR) was developed to minimize the outliers and cross-validated by testing the 530 PCs. The ddPCR was further evaluated in a subgroup of 300 PCs without mtDNA extraction and in samples from systematic variations of UVC dose and agitation speed. Apheresis PCs (n = 380) resulted in 5.3% outliers in LC PCR versus only 0.7% in buffy coat pool PCs (n = 150). Sequencing of these outliers revealed single-nucleotide polymorphisms in the primer- and probe-binding sites of LC PCR. The development of a ddPCR assay with modified probe sequences reduced the outliers to 0.4%. The ddPCR analysis of PCs both with and without mtDNA extraction demonstrated low intra- and interassay variabilities and congruent results also compared to LC PCR. Experiments varying the UVC dose and the agitation speed demonstrated that the ddPCR results closely reflect functional effects of the UVC treatment. The ddPCR assay offers a valid and reliable tool for QC of routine production of the UVC-treated PCs as well as for monitoring treatment conditions during optimization of the UVC procedure.

Blood transfusion service in Poland in 2018

Background: Assessment of the basic aspects of the activity of the Polish Regional Blood Transfusion Centers (hereinafter referred to as Centers) in 2018. Materials and methods: Retrospective analysis of the 2018-data supplied by the Centers. Results: In 2018, blood and blood components were collected in 21 Centers and 132 local collection sites as well as during 13 189 mobile collections. The overall number of blood donors was estimated at 590 470; the majority were non-remunerated donors (589 897 — including 37 824 responders to donation appeals), 73 remunerated donors and 500 autologous donors. Most frequent were whole blood collections (1 184 311), least frequent — granulocyte concentrate collections (116) and red blood cell (RBC) collection by apheresis (31 donations). Whole blood was collected mostly in local collection sites (44.85%), less frequently in Centers (28.47%) and at mobile collection sites (26.67%). Most frequently prepared blood components were RBC — 1 161 600 units) and fresh frozen plasma (FFP — 1 298 216 units; 20.93% dedicated for clinical use). Platelet concentrates (PCs) collected by apheresis amounted to 50 255 units and 83 598 were whole blood-derived. Additional processing methods such as leukocyte depletion and irradiation were more frequently applied to PCs (32.56% leukocyte depleted, 1.37% irradiated, 58.07% both leukocyte depleted and irradiated) than to RBCs (17.29% leukocyte depleted, 0.31% irradiated, 8.94% both leukocyte depleted and irradiated). Pathogen reduction technologies were applied to 11.74% of PCs and 10.23% units of FFP issued for transfusion. In 2018 — for various reasons — 14 067 units of whole blood, 30 521 units of RBC, 49 979 units of FFP, 1376 units of cryoprecipitate, 5186 units of pooled PCs and 1625 of apheresis PCs were wasted. Conclusions: The study data may contribute to evaluation of the tendencies observed in Centers and may serve practical-benchmarking which in turn may prove beneficial to the transfusion community as a whole.

Rhesus D Antigenic Determinants on Residual Red Blood Cells in Apheresis and Buffy Coat Platelet Concentrates

Background: The level of residual red blood cells (RBCs) in platelet concentrates (PCs) is of interest because of clinical concerns related to alloimmunization to RBC antigens in transfused patients. This work aims at characterizing and quantifying the levels of intact and fragmented RBCs in apheresis (AP-PCs) and buffy coat PCs (BC-PCs) to assess their potential risk for RhD antigen alloimmunization. Methods: After staining with anti-CD41 (platelets) and anti-CD235a (RBCs) antibodies, the size and density of RhD antigen on intact and fragmented RBCs were analyzed by flow cytometry. Results: Residual RBC counts were 29 ± 22 × 10⁶/unit in AP-PCs and 121 ± 54 × 10⁶/unit in BC-PCs, which correspond to about 3 and 11 µL of RBCs by product, respectively. RhD expression was about 4 times higher on RBC particles in AP-PCs, and these particles contribute to 66 and 75% of the total antigenic load in BC-PCs and AP-PCs, respectively. Conclusions: Processing methods influence the quantity and nature of contaminating residual RBCs and RBC-derived particles in PCs. The estimation of residual RBCs in these blood products is generally based on measurements of intact RBCs, which might underestimate the risk for alloim­munization in transfused patients. The question of whether these RBC-derived particles can produce an immune response and, thus, should then be taken into consideration for Rh immune prophylactic treatments, remains to be clarified.

Hypersensitivity transfusion reactions to platelet concentrate: a retrospective analysis of the French hemovigilance network.

Among labile blood products, platelet concentrates (PCs) are the leading cause of hypersensitivity transfusion reactions (HTRs). These reactions often lead to interruption of PC transfusion and can result in a prolonged transfusion process leading to significant morbidity and use of premedication and close monitoring for patients with a history of allergic transfusion reactions. The French hemovigilance database is one of the largest standardized databases providing information on HTRs following administration of labile blood products. In this study, we analyzed this database to assess the relative risk of HTR for each type of PC. HTRs following PC transfusion were retrospectively extracted from the e-Fit Hemovigilance database of the French National Agency for Medicines and Health Products Safety (ANSM). Frequencies were calculated using the number of specific PCs transfused. Between 2008 and 2014, the overall estimated incidence of HTRs following PC administration was calculated at 232 HTRs per 100,000 PCs transfused. The rate of HTRs was significantly higher with apheresis PC (337/100,000) than with buffy-coat PC (94/100,000). Platelets in additive solutions (PAS) were associated with a significantly lower frequency of HTRs when compared with PCs in native plasma. Amotosalen/UVA- PCs (APCs and BCPCs) which are always in PAS in France, exhibited the lowest frequency of HTRs when compared with their corresponding PCs in native plasma or in PAS (p < 10-7 in all comparisons). Our results showed that the type of PC and its processing may have an impact on the risk of HTR.