The New Generation of Platelet Additive Solution for Storage at 22°C: Development and Current Experience

Platelet Additive Solutions and Pathogen Reduction Impact on Transfusion Safety, Patient Management and Platelet Supply

Since 1998, leuko-reduction is used in France for all platelet concentrates (PCs), apheresis-derived (APCs) and pooled whole blood-derived buffy-coats (BCPCs). Platelet additive solutions (PAS), introduced in 2005, accounted for over 80% of the platelet supply from 2011 to 2017. The Intercept pathogen reduction technology (PR), started in a pilot study in 2007, was generalized in 2018. Between 2007 and 2021, the use of BCPCs increased steadily from 23% to 70% of the supply. Objectives: to analyze the impact of these modifications on adverse transfusion reactions (ATRs), patient management and blood transfusion organization. Results: The overall incidence of ATRs /105 PCs is significantly lower with PAS- and PR-PCs as compared to PCs in plasma (PL), with the decreasing hierarchy PL > PAS > PR. PAS- and PR-PCs lead to significantly lower incidences of allergy and alloimmunization to RBC antigens (RC-AI) ATRs. The incidence of bacteria transmission (TTBI) is significantly reduced by 95% with PR-PCs. APC-related ATR incidence is significantly higher than BCPC for allergy (+233%), TTBI (+100%), APTR (+75%), Major-ABO-II (+65%), HLA/HPA-AI (+38%), FNHTR (+22%), and life-threatening ATRs (+106%). A single diagnosis is significantly less associated with APCs: RC-AI (-47%). The generalization of PR-PCs, which exhibit a lower platelet content than PAS- and PL-PCs, is associated with a significant 9% decrease in the ATR incidence per PC, a 13% increase in the number of PCs transfused per patient, and a nonsignificant 3% increase in the ATR incidence per patient. The outdated PCs percentage declined significantly from 3.7% to 1.7%.

Single step method for high yield human platelet lysate production

BACKGROUND

We aimed to develop a single step method for the production of human platelet lysate (hPL). The method must result in high hPL yields, be closed system and avoid heparin use.

STUDY DESIGN AND METHODS

The method aimed at using glass beads and calcium. An optimal concentration of calcium and glass beads was determined by serial dilution. This was translated to a novel method and compared to known methods: freeze-thawing and high calcium. Quality outcome measures were transmittance, fibrinogen and growth factor content, and cell doubling time.

RESULTS

An optimal concentration of 5 mM Ca²⁺ and 0.2 g/ml glass beads resulted in hPL with yields of 92% ± 1% (n = 50) independent of source material (apheresis or buffy coat-derived). The transmittance was highest (56% ± 9%) compared to known methods (<39%). The fibrinogen concentration (7.0 ± 1.1 μg/ml) was well below the threshold, avoiding the need for heparin. Growth factor content was similar across hPL production methods. The cell doubling time of adipose derived stem cells was 25 ± 1 h and not different across methods. Batch consistency was determined across six batches of hPL (each n = 25 constituting concentrates) and was <11% for all parameters including cell doubling time. Calcium precipitation formed after 4 days of culturing stem cells in media with hPL prepared by the high (15 mM) Ca²⁺ method, but not with hPL prepared by glass bead method.

DISCUSSION

The novel method transforms platelet concentrates to hPL with little hands-on time. The method results in high yield, is closed system, without heparin and non-inferior to published methods.

Platelet storage: Progress so far

There is a crucial need for platelet transfusion during an emergency-surgery and treatment of platelet disorders. The unavailability of donors has furthermore increased the demand for platelet storage. Platelets have limited shelf life due to bacterial contamination and storage lesions. Temperature, materials, oxygen availability, media, platelet processing and manufacturing methods influence the platelet quality and viability during storage. The conception of various platelet additive solutions along with the advent of plastic storage during the 1980s led to enormous developments in platelet storage strategies. Cold storage of platelets gained attention despite its inability to contribute to platelet survival post-transfusion as it offers faster haemostasis. Several developments in platelet storage strategies over the years have improved the quality and shelf-life of stored platelets. Despite the progress, the efficacy of platelets during storage beyond a week has not been achieved. Antioxidants as additives have been explored in platelet storage and have proven to enhance the efficacy of platelets during prolonged storage. However, the molecular interactions of antioxidants in platelets can provide a better understanding of their mechanism of action. Optimization of dosage concentrations of antioxidants is also a critical parameter to be considered as they tend to exhibit toxicity at certain levels. This review provides comprehensive insights into the critical factors affecting platelet storage and the evolution of platelet storage. It also emphasizes the role of antioxidants as additives in platelet storage solutions and their future prospects towards better platelet banking.

Assessment of polymicrobial interactions in bacterial isolates from transfused platelet units associated with sepsis

BACKGROUND

In 2019 the Centers for Disease Control and Prevention (CDC) reported a series of 4 transfusion reactions that resulted from contamination of apheresis platelet products. Products involved in all 4 cases were contaminated with Acinetobacter calcoaceticus-baumannii complex (ACBC) and in 3 products Staphylococcus saprophyticus was found as well. CDC investigation found that bacterial isolates from the cases were genetically related and suggested a common source of contamination. The contamination of blood products with ACBC is rare and polymicrobial contamination of blood products even less common. ACBC and S. saprophyticus have been observed to adhere to one another and sediment out of suspension in vitro, a process referred to as coaggregation, and we hypothesized that there was an interaction between the strains from these cases that contributed to their co-contamination of blood products.

STUDY DESIGN AND METHODS

To test the hypothesis of bacterial interaction, we performed coaggregation experiments and observed the growth characteristics of ACBC and S. saprophyticus strains recovered from contaminated blood products involved in a subset of the CDC cases.

RESULTS

An increase in S. saprophyticus CFU concentration was observed after several days of co-culture with ACBC in LB and plasma; however, no other findings suggested coaggregation or augmentative growth interaction between the bacterial strains.

CONCLUSION

Ultimately, an interaction between ACBC and S. saprophyticus that could help explain their co-occurrence and growth in contaminated platelet units was not found; however future studies of potential interactions may be warranted.

Platelet additive solution suspended apheresis platelets in a tertiary care hospital: A step toward universal single donor platelets

BACKGROUND

Transfusion of ABO-compatible single donor platelets (SDP) is preferable for better outcomes over group switchover SDP. The use of SDP containing ABO-incompatible plasma is associated with a risk of allergic and acute hemolytic transfusion reactions. Moreover, high titer O group donors SDP impose a further threat to patient safety. Platelet additive solution (PAS) is used worldwide for the storage of platelets which reduces plasma volume available in SDP. SSP + (Macopharma) is one such PAS which can provide improved availability, logistical management, decrease wastage, and improvement in patient safety. The aim of this study was to assess the feasibility of using PAS to obtain low titer SDP units which can be utilized across a larger patient population and to study quality control parameters of these units.

MATERIALS AND METHODS

The study was performed in the department of Transfusion Medicine from June 2017 to January 2018 after clearance from the Institutional Review Board. The study design comprised two cohorts (A and B). In cohort A, the temporal trend of in-vitro changes in the quality parameters was tested and analyzed for PAS modified and unmodified products on days 1, 5 and 7. In cohort B, the original plasma from the SDP donors of all blood group donors except the AB group was tested for antibody titers before (prepreparation) and after modification (postpreparation) by PAS.

RESULTS

In cohort A, in the control group, there was a significant change in the mean platelet volume, potassium, and bicarbonate levels from day 1 to day 7, whereas no significant change in the biochemical parameters was noted in the study group where PAS was used. In cohort B, on comparing the anti-A and anti-B, before and after modification of SDP with PAS, there was a significant reduction in the median titers across all the groups studied.

CONCLUSION

PAS added SDP is an efficient strategy to reduce the ABO-antibody levels significantly. PAS added SDP also helps in the better inventory management of available groups.

Refrigeration of apheresis platelets in platelet additive solution (PAS-E) supports in vitro platelet quality to maximize the shelf-life

BACKGROUND

Refrigeration, or cold-storage, of platelets may be beneficial to extend the limited shelf-life of conventionally stored platelets and support transfusion protocols in rural and military areas. The aim of this study was to compare the morphologic, metabolic, and functional aspects of apheresis platelets stored at room-temperature (RT) or cold conditions, in either plasma or supplemented with platelet additive solution (PAS).

STUDY DESIGN AND METHODS

Double-dose apheresis platelets were collected in either 100% plasma or 40% plasma/60% PAS-E using the Trima apheresis platform. One component from each group was either stored at RT (20-24°C) or refrigerated (2-6°C). Platelets were tested over a 21-day period.

RESULTS

The platelet concentration decreased by approximately 30% in all groups during 21 days of storage (p > .05). Cold-storage reduced glycolytic metabolism, and the pH was maintained above the minimum specification (>6.4) for 21 days only when platelets were stored in PAS. The surface phenotype and the composition of the supernatant were differentially affected by temperature and storage solution. Functional responses (aggregation, agonist-induced receptor activation, clotting time) were improved during cold-storage, and the influence of residual plasma was assay dependent.

CONCLUSION

In vitro platelet quality is differentially affected by storage time, temperature, and solution. Cold-storage, particularly in PAS, better maintains key metabolic, phenotypic, and functional parameters during prolonged storage.

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.

Removal of citrate from PAS-III additive solution improves functional and biochemical characteristics of buffy-coat platelet concentrates stored for 7 days, with or without INTERCEPT pathogen reduction

BACKGROUND

Deterioration in quality of platelet concentrates (PCs) during storage results from the appearance of storage lesions affecting the hemostatic functions and posttransfusion survival of platelets. These lesions depend on the preparation and pathogen inactivation methods used, duration of storage, and platelet additive solutions (PASs) present in storage bags.

METHODS

We investigated the effects of citrate contained in third-generation PAS (PAS-III) on storage lesions in buffy-coat PCs with or without photochemical (amotosalen-ultraviolet A) treatment over 7 days.

RESULTS

Platelet counts were conserved in all groups during storage, as was platelet swirling without appearance of macroscopic aggregates. Glycoprotein (GP) IIbIIIa and GPVI expression remained stable, whereas GPIbα declined similarly in all groups during storage. Removal of citrate from PAS-III, resulting in global reduction of citrate from 11 to 5 mM, led to a significant decrease in glucose consumption, which largely countered a modest deleterious effect of photochemical treatment. Citrate reduction also resulted in decreased lactate generation and better maintenance of pH during storage, while photochemical treatment had no impact on these parameters. Moreover, citrate-free storage significantly reduced exposure of P-selectin and the apoptosis signal phosphatidylserine, thereby abolishing the activating effect of photochemical treatment on both parameters. Citrate reduction benefited platelet aggregation to various agonists up to Day 7, whereas PCT had no impact on these responses.

CONCLUSION

Removal of citrate from PAS-III has a beneficial impact on platelet metabolism, spontaneous activation, and apoptosis, and improves platelet aggregation, irrespective of photochemical treatment, which should allow transfusion of platelets with better and longer-lasting functional properties.

Antioxidant prevents clearance of hemostatically competent platelets after long-term cold storage

BACKGROUND

Cold storage of platelets (PLTs) has the potential advantage of prolonging storage time while reducing posttransfusion infection given the decreased likelihood of bacterial outgrowth during storage and possibly beneficial effects in treating bleeding patients. However, cold storage reduces PLT survival through the induction of complex storage lesions, which are more accentuated when storage is prolonged.

STUDY DESIGN AND METHODS

Whole blood-derived PLT-rich plasma concentrates from seven PLT pools (n = 5 donors per pool). PLT additive solution was added (67%/33% plasma) and the product was split into 50-mL bags. Split units were stored in the presence or absence of 1 mM of N-acetylcysteine (NAC) under agitation for up to 14 days at room temperature or in the cold and were analyzed for PLT activation, fibrinogen-dependent spreading, microparticle formation, mitochondrial respiratory activity, reactive oxygen species (ROS) generation, as well as in vivo survival and bleeding time correction in immunodeficient mice.

RESULTS

Cold storage of PLTs for 7 days or longer induces significant PLT activation, cytoskeletal damage, impaired fibrinogen spreading, enhances mitochondrial metabolic decoupling and ROS generation, and increases macrophage-dependent phagocytosis and macrophage-independent clearance. Addition of NAC prevents PLT clearance and allows a correction of the prolonged bleeding time in thrombocytopenic, aspirin-treated, immunodeficient mice.

CONCLUSIONS

Long-term cold storage induces mitochondrial uncoupling and increased proton leak and ROS generation. The resulting ROS is a crucial contributor to the increased macrophage-dependent and -independent clearance of functional PLTs and can be prevented by the antioxidant NAC in a magnesium-containing additive solution.

Comparison of ABO antibody titration, IgG subclasses and qualitative haemolysin test to reduce the risk of passive haemolysis associated with platelet transfusion

BACKGROUND

One of the strategies used to reduce the risk of haemolysis due to ABO-minor incompatible platelet transfusions is to perform a screening test to identify group O donors with high titres of anti-A and anti-B. However, critical immunoglobulin M/ immunoglobulin G (IgM/IgG) titres remain unclear.

OBJECTIVE

This study aimed to determine IgM titres of anti-A and anti-B in individual donor serum vs platelet products plasma and identify a possible association between IgM/IgG titres, haemolysin test and IgG subclasses in Brazilian blood donors from group O.

METHODS

IgM anti-A and Anti-B titration tests were performed on single-donor serum and platelet product plasma by gel agglutination (GA) at room temperature. For IgG anti-A and anti-B titration, serum was first treated with 0.01 M dithiothreitol (DTT), and the test was performed by GA with incubation at 37°C. Dilution of 1:64 as the cut-off was considered for both IgM/IgG. The qualitative haemolysin test was performed in tube, adding AB fresh serum, with incubation at 37°C. IgG subclasses were determined by GA using specific monoclonal antibodies.

RESULTS

An association between anti-A and anti-B IgM titres and haemolysin were demonstrated (P < .001). IgM titres in plasma samples from platelet components correlated to those in single-serum samples. IgG1/IgG3 subclasses were associated with total haemolysis and titres above 64, whereas IgG2/IgG4 subclasses were associated with the absence of haemolysis and titres below 64 (P < .001).

CONCLUSION

Our data suggest that a value of 64 as a critical titre can be used as a screening test of anti-A and anti-B IgM to prevent transfusion reactions. This can be a safe and cost-effective approach for managing ABO-incompatible platelet transfusions.

Quality and safety measures in transfusion practice: The experience of eight southern/eastern Mediterranean countries

BACKGROUND AND OBJECTIVES

Blood transfusion is inherently associated with risks, and little is known regarding the available quality and safety measures in developing countries. No studies or census has been carried out, and therefore, no data on this compelling issue are available.

MATERIALS AND METHODS

Data emanating from eight Arabic eastern/southern Mediterranean countries who responded to five surveys were collected and tabulated.

RESULTS

Asepsis during phlebotomy, screening for serological and immuno-haematological parameters and appropriate storage conditions are maintained across all countries. Variations in blood component processing exist. Universal leucoreduction is systematically applied in Lebanon. Nucleic acid testing is only performed in Egypt. Aphaeresis procedure, leucoreduction and quality control for blood components are virtually inexistent in Mauritania. Written donor questionnaire is absent in Algeria and Tunisia. Most donor deferral periods for infectious agents are inconsistent with international standards.

CONCLUSION

Gaps in the processing and in the quality/safety measures applied to the manufacture of blood components are quite evident in most eastern/southern Mediterranean countries. The decision of establishing an effective collaboration network and an independent body - aside from WHO - composed of specialists that oversees all transfusion activities in these countries is certainly a crucial step towards ensuring an optimum level of blood safety.

The effect of platelet storage temperature on haemostatic, immune, and endothelial function: potential for personalised medicine

Reports from both adult and paediatric populations indicate that approximately two-thirds of platelet transfusions are used prophylactically to prevent bleeding, while the remaining one-third are used therapeutically to manage active bleeding. These two indications, prophylactic and therapeutic, serve two very distinct purposes and therefore will have two different functional requirements. In addition, disease aetiology in a given patient may require platelets with different functional characteristics. These characteristics can be derived from the various manufacturing methods used in platelet product production, including collection methods, processing methods, and storage options. The iterative combinations of manufacturing methods can result in a number of unique platelet products with different efficacy and safety profiles, which could potentially be used to benefit patient populations by meeting diverse clinical needs. In particular, cold storage of platelet products causes many biochemical and functional changes, of which the most notable characterised to date include increased haemostatic activity and altered expression of molecules inherent to platelet:leucocyte interactions. The in vivo consequences, both short- and long-term, of these molecular and cellular cold-storage-induced changes have yet to be clearly defined. Elucidation of these mechanisms would potentially reveal unique biologies that could be harnessed to provide more targeted therapies. To this end, in this new era of personalised medicine, perhaps there is an opportunity to provide individual patients with platelet products that are tailored to their clinical condition and the specific indication for transfusion.

Acute Intravascular Hemolysis Following an ABO Non-Identical Platelet Transfusion: A Case Report and Literature Review

Patient: Female, 61

Final Diagnosis: Acute intravascular hemolysis

Symptoms: Cherry colored urine • chills

Medication: —

Clinical Procedure: —

Specialty: Pathology

Therapeutic Utility of Cold-Stored Platelets or Cold-Stored Whole Blood for the Bleeding Hematology-Oncology Patient

Bleeding related to thrombocytopenia is common in hematology-oncology patients. Platelets stored at room temperature (RTPs) are the current standard of care. Platelets stored in the cold (CSPs) have enhanced hemostatic function relative to RTPs. CSPs were reported to reduce bleeding in hematology-oncology patients. Recent studies have confirmed the enhanced hemostatic properties of CSPs. CSPs may be the better therapeutic option for this population. CSPs may also offer a preferable immune profile, reduced thrombotic risk, and reduced transfusion-transmitted infection risk. The logistical advantages of CSPs would improve outcomes for many patients who currently cannot access platelet transfusions.

Assessment of Time-Dependent Platelet Activation Using Extracellular Vesicles, CD62P Exposure, and Soluble Glycoprotein V Content of Platelet Concentrates with Two Different Platelet Additive Solutions

Novel analytical measures are needed to accurately monitor the properties of platelet concentrates (PCs). Since activated platelets produce platelet-derived extracellular vesicles (EVs), analyzing EVs of PCs may provide additional information about the condition of platelets. The prospect of using EVs as an auxiliary measure of platelet activation state was investigated by examining the effect of platelet additive solutions (PASs) on EV formation and platelet activation during PC storage. The time-dependent activation of platelets in PCs with PAS-B or with the further developed PAS-E was compared by measuring the exposure of CD62P by flow cytometry and the content of soluble glycoprotein V (sGPV) of PCs by an immunoassay. Changes in the concentration and size distribution of EVs were determined using nanoparticle tracking analysis. A time-dependent increase in platelet activation in PCs was demonstrated by increased CD62P ex-posure, sGPV content, and EV concentration. Using these strongly correlating parameters, PAS-B platelets were shown to be more activated compared to PAS-E platelets. Since the EV concentration correlated well with the established platelet activation markers CD62P and sGPV, it could potentially be used as a complementary parameter for platelet activation for PCs. More detailed characterization of the resulting EVs could help to understand how the PC components contribute the functional effects of transfused PCs.

Comparison of the Hemostatic Efficacy of Pathogen-Reduced Platelets vs Untreated Platelets in Patients With Thrombocytopenia and Malignant Hematologic Diseases: A Randomized Clinical Trial

IMPORTANCE

Pathogen reduction of platelet concentrates may reduce transfusion-transmitted infections but is associated with qualitative impairment, which could have clinical significance with regard to platelet hemostatic capacity.

OBJECTIVE

To compare the effectiveness of platelets in additive solution treated with amotosalen-UV-A vs untreated platelets in plasma or in additive solution in patients with thrombocytopenia and hematologic malignancies.

DESIGN, SETTING, AND PARTICIPANTS

The Evaluation of the Efficacy of Platelets Treated With Pathogen Reduction Process (EFFIPAP) study was a randomized, noninferiority, 3-arm clinical trial performed from May 16, 2013, through January 21, 2016, at 13 French tertiary university hospitals. Clinical signs of bleeding were assessed daily until the end of aplasia, transfer to another department, need for a specific platelet product, or 30 days after enrollment. Consecutive adult patients with bone marrow aplasia, expected hospital stay of more than 10 days, and expected need of platelet transfusions were included.

INTERVENTIONS

At least 1 transfusion of platelets in additive solution with amotosalen-UV-A treatment, in plasma, or in additive solution.

MAIN OUTCOMES AND MEASURES

The proportion of patients with grade 2 or higher bleeding as defined by World Health Organization criteria.

RESULTS

Among 790 evaluable patients (mean [SD] age, 55 [13.4] years; 458 men [58.0%]), the primary end point was observed in 126 receiving pathogen-reduced platelets in additive solution (47.9%; 95% CI, 41.9%-54.0%), 114 receiving platelets in plasma (43.5%; 95% CI, 37.5%-49.5%), and 120 receiving platelets in additive solution (45.3%; 95% CI, 39.3%-51.3%). With a per-protocol population with a prespecified margin of 12.5%, noninferiority was not achieved when pathogen-reduced platelets in additive solution were compared with platelets in plasma (4.4%; 95% CI, -4.1% to 12.9%) but was achieved when the pathogen-reduced platelets were compared with platelets in additive solution (2.6%; 95% CI, -5.9% to 11.1%). The proportion of patients with grade 3 or 4 bleeding was not different among treatment arms.

CONCLUSIONS AND RELEVANCE

Although the hemostatic efficacy of pathogen-reduced platelets in thrombopenic patients with hematologic malignancies was noninferior to platelets in additive solution, such noninferiority was not achieved when comparing pathogen-reduced platelets with platelets in plasma.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01789762.

Quality of irradiated and non-irradiated plateletpheresis concentrates stored in platelet additive solution

INTRODUCTION

Platelet additive solutions (PAS) allow to maintain platelet storage properties in platelet concentrates (PCs). The aim of the present study was to evaluate the in-vitro quality of irradiated and non-irradiated PCs, suspended in PAS, over a storage period of 6 days.

METHODS

Plateletpheresis donors fulfilling current eligibility criteria underwent plateletpheresis with the MCS+ blood cell separator. The PAS SSP+ was used to store platelets (PLT) for up to 6 days. Aliquots were drawn from the PCs after collection, at day 4, 5 and 6 of storage. A battery of tests was performed to analyse the quality of the PCs: PLT count, mean PLT volume (MPV), PLT activation marker CD 62, swirl, RBC and WBC contamination, pH, citrate, glucose, lactate and lactate dehydrogenase.

RESULTS

An average of 2.53 ± 0.21 × 10¹¹ PLT were collected in a product volume of 231 ± 5 mL in irradiated and 233 ± 6 mL in non-irradiated PCs, respectively. RBC- and WBC-contamination were within the allowed ranges. Δ CD62 steadily decreased in irradiated and non-irradiated PCs while the pH was well maintained over storage time. Glucose and lactate levels of irradiated and non-irradiated PCs showed characteristic pattern of PC storage within acceptable ranges.

CONCLUSION

Our data demonstrate that parameters of PC quality were well maintained over a storage period of 6 days using PAS. Irradiation had no impact on the quality of PCs. The product quality of irradiated and non-irradiated PCs met national and European guidelines.

Adding to platelet safety and life: Platelet additive solutions

BACKGROUND:

Platelet additive solutions (PAS) are crystalloid nutrient media used in place of plasma for platelet storage. They replace 60%–70% of plasma in platelet components, so the amount of storage plasma can be decreased. Platelets in PAS have lower risk for allergic transfusion reactions with equivalent clinical efficacy for controlling bleeding.

AIM:

The aim of this study is to evaluate the clinical and laboratory efficacy of PAS-platelets.

MATERIALS AND METHODS:

A total of 1674 single donor platelet (SDP) were collected in PAS in the month of June to September 2016 by different apheresis systems. The quality control tests were done on 356 units in 4 months. Total number of SDP were processed with Amicus device (n = 232), Trima Accel (n = 84), and MCS+ (n = 40). The parameters analyzed were antibody titer of anti-A and anti-B, volume, platelet count, pH, bacterial contamination, and reporting of adverse transfusion reaction. Antibody titers were checked by tube technique, and platelet counts were checked by hematology analyzer Sysmex poch 100i. The swirling was checked manually, and pH was checked with pH strips.

RESULTS:

Out of 356, 164 units were O group, 113 units were B group, 68 units were of A group, and the remaining 11 units were of AB Group. Anti-A and anti-B titer was significantly reduced in PAS-SDP and found 1:32 or less for all the units. All the units found negative for bacterial contamination. No transfusion reaction was reported of the units transfused. All other quality parameters for platelets also found satisfactory after implementing the additive solution.

CONCLUSION:

The ABO antibody titers were significantly reduced after addition of PAS. This facilitates the ABO incompatible SDP transfusion and helps in inventory management. The risk of allergic transfusion reaction decreases after reducing the amount of plasma from SDP units. Using PAS-SDP certainly improve the inventory management for platelets with no compromise on clinical and laboratory efficacy.

Platelet storage lesion in interim platelet unit concentrates: A comparison with buffy-coat and apheresis concentrates

Platelet storage lesion is characterized by morphological changes and impaired platelet function. The collection method and storage medium may influence the magnitude of the storage lesion. The aim of this study was to compare the newly introduced interim platelet unit (IPU) platelet concentrates (PCs) (additive solution SSP+, 40% residual plasma content) with the more established buffy-coat PCs (SSP, 20% residual plasma content) and apheresis PCs (autologous plasma) in terms of platelet storage lesions. Thirty PCs (n=10 for each type) were assessed by measuring metabolic parameters (lactate, glucose, and pH), platelet activation markers, and in vitro platelet aggregability on days 1, 4, and 7 after donation. The expression of platelet activation markers CD62p (P-selectin), CD63 (LAMP-3), and phosphatidylserine was measured using flow cytometry and in vitro aggregability was measured with multiple electrode aggregometry. Higher platelet activation and lower in vitro aggregability was observed in IPU than in buffy-coat PCs on day 1 after donation. In contrast, metabolic parameters, expression of platelet activation markers, and in vitro aggregability were better maintained in IPU than in buffy-coat PCs at the end of the storage period. Compared to apheresis PCs, IPU PCs had higher expression of activation markers and lower in vitro aggregability throughout storage. In conclusion, the results indicate that there are significant differences in platelet storage lesions between IPU, buffy-coat, and apheresis PCs. The quality of IPU PCs appears to be at least comparable to buffy-coat preparations. Further studies are required to distinguish the effect of the preparation methods from storage conditions.

Functional assessment of autologous platelet-rich plasma (PRP) after long-term storage at -20 °C without any preservation agent

BACKGROUND

Platelet-rich plasma (PRP) is increasingly being used in the treatment of chronic wounds, pathologies of the musculoskeletal system, and in cosmetic medicine; however, the preparation of platelet-rich plasma is both time-consuming and requires invasive intervention. Additional costs are introduced if special equipment is used during preparation. The aim of the present study is to test whether autologous platelet-rich plasma (PRP) preserves the feature of growth factor release when stored at -20 °C after preparation.

METHOD

Autologous PRP concentrates were prepared using whole blood samples obtained from 20 healthy subjects and divided into three parts to form three groups. Epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), platelet derived growth factor-AB (PDGF-AB), insulin-like growth factor 1 (IGF-1), transforming growth factor-beta (TGF-β), and P-Selectin levels were immediately analysed in the control group. The other groups were defined as the experimental groups and were stored at -20 °C and analysed on the 7th and the 14th days. The same growth factors were tested in the experimental groups.

RESULTS

The growth factors (EGF, VEGF, PDGF-AB, IGF-1, TGF-β) and P-selectin levels were significantly decreased in the autologous PRP samples stored at -20 °C compared to the control group.

CONCLUSION

The growth factor levels on days 7 and 14 suggest that autologous PRP can be stored at -20 °C without preservative agents, although in vivo studies are required in order to evaluate the clinical efficacy of the detected growth factor levels.

Assessment of quality of platelets preserved in plasma and platelet additive solution: A Malaysian experience

BACKGROUND

A use of platelet additives solution (PAS) improves storage conditions so as to give increased shelf life to platelets and to maintain hemostatic function.

OBJECTIVE

The present study was aimed to compare in vitro quality of platelet rich plasma (PRP)-derived platelet concentrate (PC) during extended period of storage in plasma and in additive solution (Composol PS and Fresenius).

STUDY DESIGN

Randomized 19 PCs each were used in the study for plasma and PAS as the storage medium. The measurement parameters, including pH, total white blood cell (WBC) count, total platelet count, and platelet activation rate, were studied on day 1, day 5, and day 8 of the storage period. The sterility test was carried out on the eighth day of storage.

RESULTS

pH of PC suspended in PAS was significantly lower as compared to that in plasma (P < 0.001) for all the three days of sampling. The WBC count, both in plasma and in PAS, showed an acceptable values of being <0.2 Χ 10(9) /unit during the storage period. Platelet count in PAS was higher as compared to that in plasma, though it was not statistically significant. While both the groups showed increased platelet activation rate during the storage, the PCs suspended in PAS showed significantly higher platelet activation rate (p0.001). Results from sterility test showed no bacterial growth in the PCs in both the groups.

CONCLUSION

Most parameters studied on platelet storage in suspending medium of native plasma and PAS remained well within the acceptable limits. However, the pH values and platelet activation rate significantly differed in PAS as compared with plasma.

In vitro evaluation of platelet concentrates suspended in additive solution and treated for pathogen reduction: effects of clumping formation

BACKGROUND

Platelet concentrates may demonstrate visual, macroscopic clumps immediately after collection following aphaeresis or production from whole blood, independently of the preparation method or equipment used. The relationship between the occurrence of clumping and their effect on in vitro quality of platelets was investigated.

MATERIAL AND METHODS

Platelet concentrates, suspended in SSP+ additive solution (Macopharma), were obtained by automated processing and also from routine processing. A total of twelve units were allocated to the test group (n=12) due to the presence of clumps. Platelet concentrates without clumps were used as controls (n=10). All platelet units were treated for pathogen reduction following storage under continuous agitation for in vitro testing over a 9-day storage period.

RESULTS

No significant differences were found throughout storage between the groups. The lactate dehydrogenase levels increased in both groups; this increase was higher in the test group on the last day of testing, without there being a significant difference on day 2. In contrast, pH values on day 2 were significantly different between the test and control groups. Platelet-derived cytokines increased comparably during storage.

DISCUSSION

The results confirm good in vitro quality and storage stability of platelets suspended in SSP+ and treated with the Intercept pathogen reduction system. The presence of "non-compacted" clumps in platelet concentrates does not appear to affect the in vitro quality of the platelets.

Platelet transfusion - the art and science of compromise

SUMMARY

Many modern therapies depend on platelet (PLT) transfusion support. PLTs have a 4- to 7-day shelf life and are frequently in short supply. In order to optimize the inventory PLTs are often transfused to adults without regard for ABO compatibility. Hemolytic reactions are infrequent despite the presence of 'high titer' anti-A and anti-B antibodies in some of the units. Despite the low risk for hemolysis, some centers provide only ABO identical PLTs to their recipients; this practice might have other beneficial outcomes that remain to be proven. Strategies to mitigate the risk of hemolysis and the clinical and laboratory outcomes following ABO-matched and mismatched transfusions will be discussed. Although the PLTs themselves do not carry the D antigen, a small number of RBCs are also transfused with every PLT dose. The quantity of RBCs varies by the type of PLT preparation, and even a small quantity of D+ RBCs can alloimmunize a susceptible D- host. Thus PLT units are labeled as D+/-, and most transfusion services try to prevent the transfusion of D+ PLTs to D- females of childbearing age. A similar policy for patients with hematological diseases is controversial, and the elements and mechanisms of anti-D alloimmunization will be discussed.

Effects of platelet concentrate storage time reduction in patients after blood stem cell transplantation

OBJECTIVE

To evaluate the clinical effect of platelet concentrate (PC) transfusions after PC storage time reduction to 4 days.

PATIENTS AND METHODS

This was a single-centre cohort study comparing two 3-month periods of time, before and after the reduction of PC storage time from 5 to 4 days. Seventy-seven consecutive patients with PC transfusions were enrolled after blood stem cell transplantation. Corrected platelet count increment (CCI) on the morning after transfusion, time to next platelet transfusion, need for red blood cell (RBC) transfusion and clinical bleeding symptoms were compared.

RESULTS

Platelet concentrate storage time was reduced between period 1 (storage for up to 5 days, median storage time 78 h, range 11-136 h) and period 2 (storage for up to 4 days, median storage time 53 h, range 11-112 h). Patients were comparable for age, weight, body surface area, underlying disorder, type of transplantation and transfused platelet dose. The CCI increased from a median of 4 (range 0-20) to 8 (0-68) × 10(9) /l per 10(11) platelets/m(2) (P < 0·0001). Time to next PC transfusion increased from 1·1 to 2·0 days (P < 0·0001). Any bleeding symptom was noted in 20 of 36 patients (56%) vs. 9/41 patients (22%, P < 0·01). Nose bleeds, haematuria and bleeding at more than one site were significantly reduced. Frequency of RBC transfusion within 5 days after PC transfusion was reduced from 74 to 58% (P < 0·0001).

CONCLUSION

Platelet concentrate storage time shortening was associated with highly significant CCI increase, reduced RC needs and lower patient numbers with bleeding events.

Impact of glucose and acetate on the characteristics of the platelet storage lesion in platelets suspended in additive solutions with minimal plasma

BACKGROUND AND OBJECTIVES

Glucose and acetate have been proposed to be required elements in platelet storage media. This study investigated the role of these compounds on the varied elements that comprise the platelet storage lesion.

MATERIALS AND METHODS

For each replicate, four pooled and split ABO group-specific buffy coat-derived platelet concentrates were suspended in an in-house additive solution with minimal plasma and varying final concentrations of acetate or glucose. Units were sampled on days 2, 3, 6, 8 and 10 and tested for markers of platelet morphology, activation, function, metabolism and indicators of cell death.

RESULTS

The absence of glucose was associated with a decrease in ATP, falling to a mean of 1·1 ± 0·1 μmol/10(11) plts in units with no added glucose compared with 4·2 ± 0·6 μmol/10(11) plts (P < 0·001) in units with 30 mm glucose. As glucose became depleted, the decrease in ATP to levels below 3 μmol/10(11) plts was associated with an increase in both annexin V binding and intracellular free calcium. In units lacking exogenous acetate, ATP levels on day 10 were 5·2 ± 1·5 μmol/10(11) plts compared with 2·7 ± 0·9 μmol/10(11) plts in units with 56 mm acetate (P = 0·006). Higher concentrations of exogenous acetate were associated with a lower hypotonic shock response and higher surface expression of CD62P suggestive of a dose dependency.

CONCLUSION

Under current physical storage conditions, glucose appears necessary for the maintenance of platelets stored as concentrates in minimal volumes of plasma. The addition of acetate was associated with increased platelet activation and reduced ATP levels.

Early storage lesions in apheresis platelets are induced by the activation of the integrin αIIbβ₃ and focal adhesion signaling pathways

Production and storage of platelet concentrates (PC) induce protein changes in platelets leading to impaired platelet function. This study aimed to identify signaling pathways involved in the development of early platelet storage lesions in apheresis-PCs stored in plasma or additive solution (PAS). Apheresis-PCs from four donors were stored in plasma or in PAS at 22°C (n=4 each). Platelets were analyzed at day 0 (production day) and after 1, 6 and 9 days of storage. Platelet response to agonists (TRAP, collagen, ADP) and to hypotonic shock decreased, CD62P expression increased in both storage media over time. Using DIGE 1550 protein spots were monitored and compared to baseline values at day 0. Platelets in plasma displayed changes in 352 spots (166/day 1, 263/day 6 and 201/day 9); in PAS 325 spots changed (202/day 1, 221/day 6, 200/day 9). LC-ESI-MS/MS analysis of 405 platelet proteins revealed 32 proteins changed during storage in plasma (9/day 1, 15/day 6 and 26/day 9) and 28 in PAS (5/day 1, 20/day 6, 26/day 9). Ingenuity pathway analysis found integrin-αII(b)β(3) and focal adhesion signaling pathways involved in early alterations, being confirmed by Western blotting. Corresponding mRNAs in platelets were identified by next generation sequencing for 84 changed proteins. Integrin-αII(b)β(3) and focal adhesion signaling cause irreversible early storage lesions in apheresis platelets. This article is part of a Special Issue entitled: Integrated omics.

Evaluation of platelet function during extended storage in additive solution, prepared in a new container that allows manual buffy-coat platelet pooling and leucoreduction in the same system

BACKGROUND

A novel and practical storage container designed for manual buffy-coat pooling and leucodepletion was evaluated to assess its filtration performance and to analyse the quality of stored leucoreduced buffy-coat-derived platelet pools.

MATERIALS AND METHODS

To analyse the grifols leucored transfer PL system, blood was collected from random donors into standard triple bag systems, and fractionated using standard procedures to obtain buffy-coats. Ten leucodepleted platelet pools were prepared each from five units of buffy-coats in additive solution. Concentrates were stored for 10 days at 22 °C on an end-over-end agitator. On days 0, 5, 7, and 10 of storage, samples were tested using standard in vitro platelet parameters.

RESULTS

The use of this novel system for volume reduction and leucodepletion of buffy-coats resuspended in additive solution led to platelet pools that met the European requirements. pH was maintained well, declining from an initial value of 7.11±0.04 to 6.88±0.08 after 10 days. Parameters of cell lysis, response to a hypotonic stimulus and aggregation induced by agonists (arachidonic acid, ristocetin, collagen or thrombin receptor activating peptide) were also well-preserved. During storage, the quality profile of the platelet pools remained very similar to that previously reported in platelet concentrates in terms of metabolism, platelet activation (CD62, CD63, sCD62), expression of glycoproteins Ib and IIb/IIIa, capacity of glycoprotein IIb/IIIa to become activated upon ADP stimulation, and release of biological response modifiers (sCD40L and RANTES).

DISCUSSION

This new system allows the preparation of leucodepleted buffy-coat platelet pools in additive solution with good preservation of platelet function. The logistics of the procedure are relatively simple and it results in good-quality components, which may reduce costs and ease the process of buffy-coat pooling and leucocyte reduction in transfusion services.

Glucose ameliorates the metabolic profile and mitochondrial function of platelet concentrates during storage in autologous plasma

BACKGROUND

It is essential that the quality of platelet metabolism and function remains high during storage in order to ensure the clinical effectiveness of a platelet transfusion. New storage conditions and additives are constantly evaluated in order to achieve this. Using glucose as a substrate is controversial because of its potential connection with increased lactate production and decreased pH, both parameters triggering the platelet lesion during storage.

MATERIALS AND METHODS

In this study, we analysed the morphological status and metabolic profile of platelets stored for various periods in autologous plasma enriched with increasing glucose concentrations (13.75, 27.5 and 55 mM). After 0, 2, 4, 6 and 8 days, high energy phosphates (ATP, GTP, ADP, AMP), oxypurines (hypoxanthine, xanthine, uric acid), lactate, pH, mitochondrial function, cell lysis and morphology, were evaluated.

RESULTS

The data showed a significant dose-dependent improvement of the different parameters in platelets stored with increasing glucose, compared to what detected in controls. Interestingly, this phenomenon was more marked at the highest level of glucose tested and in the period of time generally used for platelet transfusion (0-6 days).

CONCLUSION

These results indicate that the addition of glucose during platelet storage ameliorates, in a dose-dependent manner, the biochemical parameters related to energy metabolism and mitochondrial function. Since there was no correspondence between glucose addition, lactate increase and pH decrease in our experiments, it is conceivable that platelet derangement during storage is not directly caused by glucose through an increase of anaerobic glycolysis, but rather to a loss of mitochondrial functions caused by reduced substrate availability.

Preparation of single donor platelet with low antibody titers for all patients

Platelet concentrates from ABO-identical donors are the components of choice for patients. However, since inventories are generally insufficient and because there is usually a relative abundance of group O donors, perfect matches are not always possible. It is therefore the accepted practice for platelets to be transfused out of the ABO group when ABO-identical platelets are unavailable. Notwithstanding, the transfusion of platelets containing high titers of antibodies to the antigens on the red blood cells of the patient can cause clinically significant hemolysis. The way to improve the safety of group O platelets has focused on defining a safe level of antibodies or reducing the volume of incompatible plasma. In the current study, 107 group O single donor platelets (SDP) were modified after collecting the platelet pellet in a bag. The AB plasma was added instead of the donor's own plasma. The direct agglutination titers of anti-A/anti-B in the original group O SDPs' plasma were performed by doing a gel test, resulting in from 1:4 to 1:1024. The prevalence of high titers (i.e., at least 1:64 in our study) was relatively high, ∼63% for anti-A and 78% for anti-B. The titer of residual anti-A/anti-B in the modified SDPs ranged from negative to 1:8. In most of the modified SDPs anti-A/anti-B could not be detected in the plasma (58.9% and 52.3%, respectively). The results indicate that our modified SDPs have very low titers; that is, acting as a universal SDP which is safe for all ABO patients. This modified SDP form is a more convenient way to overcome the risk from incompatible plasma or loss of platelets during the process of volume reduction and can help effectively manage our inventory.

In vitro function of random donor platelets stored for 7 days in composol platelet additive solution

Background and Aim:

Platelets are routinely isolated from whole blood and stored in plasma for 5 days. This study was done to assess the in vitro function of random donor platelets stored for 7 days in composol platelet additive solution at 22°C.

Materials and Methods:

The study sample included 30 blood donors of both sex in State Blood Bank, C S M Medical University, Lucknow. Random donor platelets were prepared by the platelet-rich plasma method. Whole blood (350 ml) was collected in anticoagulant Citrate Phosphate Dextrose Adenine triple blood bags. Random donor platelets were stored for 7 days at 22°C in platelet incubators and agitators with and without additive solution.

Results:

Platelet swirling was present in all the units at 22°C on day 7 with no evidence of bacterial contamination. Comparison of the mean values of platelet count, platelet factor 3, lactate dehydrogenase, pH, glucose and platelet aggregation showed no significant difference in additive solution while platelet factor 3, glucose and platelet aggregation showed significant difference (P < 0.001) on day 7 without additive solution at 22°C.

Conclusion:

Our study infers that the platelet viability and aggregation were the best maintained within normal levels on day 7 of storage in platelet additive solution at 22°C. Thus, we may conclude that in vitro storage of random donor platelets with an extended shelf life of 7 days using platelet additive solution may be advocated to improve the inventory of platelets.

In vitro function of random donor platelets stored for 7 days in composol platelet additive solution

BACKGROUND AND AIM

Platelets are routinely isolated from whole blood and stored in plasma for 5 days. The present study was done to assess the in vitro function of random donor platelets stored for 7 days in composol platelet additive solution at 22°C.

MATERIALS AND METHODS

The study sample included 30 blood donors of both sex in State Blood Bank, CSM Medical University, Lucknow. Random donor platelets were prepared by platelet rich plasma method. Whole blood (350 ml) was collected in anticoagulant Citrate Phosphate Dextrose Adenine triple blood bags. Random donor platelets were stored for 7 days at 22°C in platelet incubators and agitators, with and without additive solution.

RESULTS

Platelet swirling was present in all the units at 22°C on day 7, with no evidence of bacterial contamination. Comparison of the mean values of platelet count, platelet factor 3, lactate dehydrogenase, pH, glucose and platelet aggregation showed no significant difference in additive solution, whereas platelet factor 3, glucose and platelet aggregation showed significant difference (P < 0.001) on day 7 without additive solution at 22°C.

CONCLUSION

Our study infers that platelet viability and aggregation were best maintained within normal levels on day 7of storage in platelet additive solution at 22°C. Thus, we may conclude that in vitro storage of random donor platelets with an extended shelf life of 7 days using platelet additive solution may be advocated to improve the inventory of platelets.

Impact of sample volume and handling time during analysis on the in vitro quality measurements of platelet concentrates held in syringes

INTRODUCTION

The determination of quality parameters is a necessity for monitoring the efficacy of platelet concentrates. During consolidated quality control studies, there may be a large number of samples to be analyzed at the same time. This common workflow setup triggered the question whether there is an influence of the number of samples to be analyzed on the accuracy of the test results.

METHODS

Two different sample volumes of platelet concentrates, 1 ml and 50 ml, were analyzed for a set of standard in vitro parameters including pCO(2), pO(2), pH, glucose, and lactate as well as platelet activation via CD62P expression and responsiveness to adinosine diphosphate in an extent-of-shape-change assay. To assess apoptotic mechanisms triggered by the hold time, changes in the phosphatidylserine exposure were monitored.

RESULTS

In total, eleven time points were assessed over a 3-h period as well as an overnight point for assay evaluation. Except for pCO(2) and pO(2), all in vitro parameters analyzed were unaffected by a sample hold time of up to 3-h.

CONCLUSION

Sampling for pO(2) determination should be carried out in small volumes and assessed within 30 min of collection to obtain reliable and comparable results.

Overview on platelet preservation: better controls over storage lesion

Platelet storage lesion (PSL), correlating with reduced in vivo recovery/survival and hemostatic capacity after transfusion, is characterized essentially by morphological and molecular evidence of platelet activation and energy consumption in the medium. Processes that limit shelf-life are multifactorial, and include both necrosis and apoptosis. PSL is greatly influenced by factors including duration of storage, temperature, ratio of platelet number to media volume, solution composition with respect to energy content and buffering capacity, and gas permeability of the container. Recent progress for slowing PSL has been made with storage media that more effectively fuel ATP production and buffer the inevitable effects of metabolism. Improved oxygen-permeability of containers also helps to maintain aerobic-dominant glycolysis. Patients stand to benefit from platelet products of higher intrinsic quality that store well until the moment of transfusion.

Cryopreservation of buffy-coat-derived platelet concentrates in dimethyl sulfoxide and platelet additive solution

Platelets prepared in plasma can be frozen in 6% dimethyl sulfoxide (Me(2)SO) and stored for extended periods at -80°C. The aim of this study was to reduce the plasma present in the cryopreserved product, by substituting plasma with platelet additive solution (PAS; SSP+), whilst maintaining in vitro platelet quality. Buffy coat-derived pooled leukoreduced platelet concentrates were frozen in a mixture of SSP+, plasma and 6% Me(2)SO. The platelets were concentrated, to avoid post-thaw washing, and frozen at -80°C. The cryopreserved platelet units (n=9) were rapidly thawed at 37°C, reconstituted in 50% SSP+/plasma and stored at 22°C. Platelet recovery and quality were examined 1 and 24h post-thaw and compared to the pre-freeze samples. Upon thawing, platelet recovery ranged from 60% to 80%. However, there were differences between frozen and liquid-stored platelets, including a reduction in aggregation in response to ADP and collagen; increased CD62P expression; decreased viability; increased apoptosis and some loss of mitochondrial membrane integrity. Some recovery of these parameters was detected at 24h post-thaw, indicating an extended shelf-life may be possible. The data suggests that freezing platelets in 6% Me(2)SO and additive solution produces acceptable in vitro platelet quality.