A multicenter randomized study of the efficacy of transfusions with platelets stored in platelet additive solution II versus plasma

Changes in the incidence of transfusion reactions in hematological patients over the past 30 years

BACKGROUND

Patients with hematological diseases are polytransfused and often immunocompromised, therefore susceptible to transfusion reactions (TR). This study aims to document the incidence of TRs in adult hematological patients and assess the effect of changes in the production of blood components and transfusion practice on their occurrence.

STUDY DESIGN AND METHODS

Retrospective observational analysis of TRs reported from 1993 to 2019 was performed. For the analysis of the effect of changes on the incidence of TRs, the evaluated time was divided into two periods: the 1st period before the introduction of changes in production, when leukoreduced blood components were used only selectively, and the 2nd period, when semi-automated method of production and universal leukoreduction was introduced.

RESULTS

The decrease in the incidence of TRs was observed for both red blood cell (RBC) and platelet concentrate (PC) transfusions in the 2nd period. Since platelet additive solution has been used, a further decrease in the incidence was reported. The decrease in incidence was also observed for delayed hemolytic/serological transfusion reactions and for transfusion-transmitted bacterial infections. Four cases of incorrect blood transfusions were uniquely related to the hematological patients, caused by antigen loss and transfusion ordering after ABO-incompatible hematopoietic stem cell transplantation.

DISCUSSION

Our results provided evidence that the introduction of tools offered by modern transfusion medicine: universal leukodepletion, plasma replacement with additive solutions, sensitive laboratory techniques, prophylactic antigen matching policy, informatization, and automatization, decreased the incidence of TRs and improved transfusion safety.

Platelet transfusion practice and related transfusion reactions in a large teaching hospital

BACKGROUND

Platelet transfusion practice varies widely since many aspects of platelet concentrate (PC) use have not been definitively determined. The objectives of this retrospective study were to present platelet transfusion practice and evaluate PC and patient characteristics, as well as their association with transfusion reaction (TR) rate.

MATERIAL AND METHODS

Platelet transfusions over a 5-year period were analysed regarding PC characteristics (the ABO and RhD compatibility, product type, and storage duration), patient characteristics (most responsible diagnosis, age, and gender), and TR type.

RESULTS

A total of 46,351 PCs were transfused: 76.4% whole blood-derived (WBD) and 23.6% single donor apheresis (SDA). Three thousand seven hundred seventy-six patients received platelet transfusions: 24.7% paediatric and 75.3% adult patients, 79.6% outpatients and 20.4% inpatients. As much as 63.1% of all transfused PCs were fresh (stored for≤3 days), 98.0% ABO-identical, and 87.3% of all PCs given to RhD- patients were RhD-. PCs were mainly transfused to haemato-oncology (76.8%) and cardiovascular surgery patients (6.5%). Overall, 84 (0.18%) TRs were reported, with allergic TRs (ATRs) being the most common. Although PC ABO compatibility and storage duration, as well as patient age and gender, showed differences in TR rate, only the use of PCs in platelet additive solution (PAS) showed a statistically significant reduction of TRs (P<0.001).

CONCLUSION

Transfusion practice at the University Hospital Centre Zagreb resulted in almost all patients receiving ABO and RhD identical PCs, and most of them were fresh PCs. The most important factor affecting the incidence of TRs was platelet storage solution. The use of PAS effectively reduced the rate of TRs, particularly allergic TRs.

Efficacy of UVC-treated, pathogen-reduced platelets versus untreated platelets: a randomized controlled non-inferiority trial

Pathogen reduction (PR) technologies for blood components have been established to reduce the residual risk of known and emerging infectious agents. THERAFLEX UV-Platelets, a novel ultraviolet C (UVC) light-based PR technology for platelet concentrates, works without photoactive substances. This randomized, controlled, double-blind, multicenter, non-inferiority trial was designed to compare the efficacy and safety of UVC-treated platelets to that of untreated platelets in thrombocytopenic patients with hematologic-oncologic diseases. The primary objective was to determine non-inferiority of UVC-treated platelets, assessed by the 1-hour corrected count increment (CCI) in up to eight per-protocol platelet transfusion episodes. Analysis of the 171 eligible patients showed that the defined non-inferiority margin of 30% of UVC-treated platelets was narrowly missed as the mean differences in 1-hour CCI between standard platelets versus UVC-treated platelets for intention-to-treat and per-protocol analyses were 18.2% (95% Confidence Interval [CI]: 6.4-30.1) and 18.7% (95% CI: 6.3-31.1), respectively. In comparison to the control, the UVC group had a 19.2% lower mean 24-hour CCI and was treated with an about 25% higher number of platelet units, but the average number of days to the next platelet transfusion did not differ significantly between both treatment groups. The frequency of low-grade adverse events was slightly higher in the UVC group and the frequencies of refractoriness to platelet transfusion, platelet alloimmunization, severe bleeding events, and red blood cell transfusions were comparable between groups. Our study suggests that transfusion of pathogen-reduced platelets produced with the UVC technology is safe but non-inferiority was not demonstrated. (clinicaltrials gov. Identifier: DRKS00011156).

Cryopreserved buffy-coat-derived platelets reconstituted in platelet additive solution: A safe and available product with sufficient haemostatic effectiveness

BACKGROUND

Platelets (PLTs) stored at 20-24 °C have a short shelf life of only 5 days, which can result in their restricted availability. PLT cryopreservation extends the shelf life to 2 years.

METHODS

We implemented a method of PLT freezing at -80 °C in 5-6% dimethyl sulfoxide. Buffy-coat-derived leucodepleted fresh PLTs blood group O (FP) were used for cryopreservation. Cryopreserved pooled leucodepleted PLTs (CPP) were thawed at 37 °C, reconstituted in PLT additive solution SSP + and compared to FP regarding PLT content, PLT concentration, pH, volume, PLT loss, anti-A/B antibody titre, total protein, plasma content, and PLT swirling. Clot properties were evaluated via rotational thromboelastometry. PLT microparticle number and surface receptor phenotype were assessed via flow cytometry.

RESULTS

CPP met the required quality parameters. The mean freeze-thaw PLT loss was 22.24 %. Anti-A/B antibody titre and plasma content were significantly lower in CPP. CPP were characterised by faster clot initiation and form stable PLT clots. The number of PLT microparticles increased 25 times in CPP and there were more particles positive for the activation marker CD62 P compared to FP.

CONCLUSION

Thawing and reconstitution are easy and fast processes if platelet additive solution is used. Low anti-A/B antibody titre and plasma content make possible the use of CPP of blood group O reconstituted in SSP + as universal ABO products, including clinical situations where washed PLTs are required. Clot properties evaluated via rotational thromboelastometry demonstrated that CPP retain a significant part of their activity compare to FP and are haemostatically effective.

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.

Minor impact of patient alloantibodies against human platelet antigen (HPA)-15 in the effectiveness of platelet transfusion: A pilot study

BACKGROUND

Alloantibodies against human platelet antigen (HPA)-15 are sometimes detected in patients with platelet transfusion refractoriness (PTR); however, little is known about their impact on PTR.

STUDY DESIGN AND METHODS

Two patients who possessed HPA-15 alloantibodies (Patient 1, anti-HPA-15b; Patient 2, anti-HPA-15a) and human leukocyte antigen (HLA) antibodies were enrolled. The efficacy of HPA-15-compatible vs -incompatible platelet transfusion was compared by focusing on ABO- and HLA-matched transfusions on the basis of the 24-hour corrected count increment (CCI-24 hours) for platelets. The titers of HPA-15 antibodies in the patients' sera were also monitored.

RESULTS

The patients received 71 and 12 ABO-compatible, HLA-matched platelet transfusions, respectively, during the monitoring periods. Among these transfusions, CCI-24 hours could be calculated in 27 and 10 transfusions, respectively, and the HPA-15 genotype of the donors was determined. There were no significant differences in the CCI-24 hours between the HPA-15 compatible and incompatible transfusions in both patients (P = .30 and .56, respectively, Mann-Whitney U test). There was no significant change in the HPA-15b antibody titer in Patient 1 during the monitoring period, while the HPA-15a antibody level in Patient 2 was undetectable at the end of the monitoring period, although the titer was low at the beginning.

CONCLUSION

The efficacy of HPA-15-incompatible platelet transfusions was not necessarily inferior to that of HPA-15 compatible ones. Although the case number was limited, our results suggest that HPA-15 antibodies do not have a significant impact on the effects of platelet transfusion.

Retrospective cohort studies of repeat donors reveal donor-dependent variability in the recovery of transfused platelets

BACKGROUND

The in vivo recovery of transfused platelets is variable and often unpredictable. Although many recipient-dependent factors are well described, donor-dependent variables remain poorly understood.

STUDY DESIGN AND METHODS

To explore donor-dependent variables we conducted 2 retrospective studies of platelet transfusion outcomes in repeat donors. One study analyzed multiple autologous, radiolabeled platelet transfusions, and a second study analyzed multiple clinical platelet transfusions from a small cohort of repeat donors.

RESULTS

In 36 subjects, multiple within-subject determinations of recovery and survival of radiolabeled autologous platelets revealed a relative consistency in platelet recoveries within donors compared to the range of recoveries among donors. Intraclass correlation coefficients for platelet recovery were 43% to 93%. In 524 ABO-compatible clinical platelet transfusions derived from seven donors, a linear mixed-effects model revealed significant donor-dependent differences in corrected count increments for units stored for 4 or 5 days.

CONCLUSIONS

These two studies indicate reproducible donor-dependent differences in transfused platelet recovery, suggesting a possible heritable influence on the quality of transfused platelets.

Clinical-grade cryopreserved doxorubicin-loaded platelets: role of cancer cells and platelet extracellular vesicles activation loop

BACKGROUND

Human platelets (PLT) and PLT-extracellular vesicles (PEV) released upon thrombin activation express receptors that interact with tumour cells and, thus, can serve as a delivery platform of anti-cancer agents. Drug-loaded nanoparticles coated with PLT membranes were demonstrated to have improved targeting efficiency to tumours, but remain impractical for clinical translation. PLT and PEV targeted drug delivery vehicles should facilitate clinical developments if clinical-grade procedures can be developed.

METHODS

PLT from therapeutic-grade PLT concentrate (PC; N > 50) were loaded with doxorubicin (DOX) and stored at - 80 °C (DOX-loaded PLT) with 6% dimethyl sulfoxide (cryopreserved DOX-loaded PLT). Surface markers and function of cryopreserved DOX-loaded PLT was confirmed by Western blot and thromboelastography, respectively. The morphology of fresh and cryopreserved naïve and DOX-loaded PLT was observed by scanning electron microscopy. The content of tissue factor-expressing cancer-derived extracellular vesicles (TF-EV) present in conditioned medium (CM) of breast cancer cells cultures was measured. The drug release by fresh and cryopreserved DOX-loaded PLT triggered by various pH and CM was determined by high performance liquid chromatography. The thrombin activated PEV was analyzed by nanoparticle tracking analysis. The cellular uptake of DOX from PLT was observed by deconvolution microscopy. The cytotoxicities of DOX-loaded PLT, cryopreserved DOX-loaded PLT, DOX and liposomal DOX on breast, lung and colon cancer cells were analyzed by CCK-8 assay.

RESULTS

15~36 × 106 molecules of DOX could be loaded in each PLT within 3 to 9 days after collection. The characterization and bioreactivity of cryopreserved DOX-loaded PLT were preserved, as evidenced by (a) microscopic observations, (b) preservation of important PLT membrane markers CD41, CD61, protease activated receptor-1, (c) functional activity, (d) reactivity to TF-EV, and (e) efficient generation of PEV upon thrombin activation. The transfer of DOX from cryopreserved PLT to cancer cells was achieved within 90 min, and stimulated by TF-EV and low pH. The cryopreserved DOX-loaded PLT formulation was 7~23-times more toxic to three cancer cells than liposomal DOX.

CONCLUSIONS

Cryopreserved DOX-loaded PLT can be prepared under clinically compliant conditions preserving the membrane functionality for anti-cancer therapy. These findings open perspectives for translational applications of PLT-based drug delivery systems.

Platelet Transfusion Practices in Critically Ill Children

OBJECTIVES

Little is known about platelet transfusions in pediatric critical illness. We sought to describe the epidemiology, indications, and outcomes of platelet transfusions among critically ill children.

DESIGN

Prospective cohort study.

SETTING

Multicenter (82 PICUs), international (16 countries) from September 2016 to April 2017.

PATIENTS

Children ages 3 days to 16 years prescribed a platelet transfusion in the ICU during screening days.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Over 6 weeks, 16,934 patients were eligible, and 559 received at least one platelet transfusion (prevalence, 3.3%). The indications for transfusion included prophylaxis (67%), minor bleeding (21%), and major bleeding (12%). Thirty-four percent of prophylactic platelet transfusions were prescribed when the platelet count was greater than or equal to 50 × 10 cells/L. The median (interquartile range) change in platelet count post transfusion was 48 × 10 cells/L (17-82 × 10 cells/L) for major bleeding, 42 × 10 cells/L (16-80 × 10 cells/L) for prophylactic transfusions to meet a defined threshold, 38 × 10 cells/L (17-72 × 10 cells/L) for minor bleeding, and 25 × 10 cells/L (10-47 × 10 cells/L) for prophylaxis in patients at risk of bleeding from a device. Overall ICU mortality was 25% but varied from 18% to 35% based on indication for transfusion. Upon adjusted analysis, total administered platelet dose was independently associated with increased ICU mortality (odds ratio for each additional 1 mL/kg platelets transfused, 1.002; 95% CI, 1.001-1.003; p = 0.005).

CONCLUSIONS

The majority of platelet transfusions are given as prophylaxis to nonbleeding children, and significant variation in platelet thresholds exists. Studies are needed to clarify appropriate indications, with focus on prophylactic transfusions.

Platelet Storage Lesions: What More Do We Know Now?

Platelet concentrate (PC) transfusions are a lifesaving adjunct to control and prevent bleeding in cancer, hematologic, surgical, and trauma patients. Platelet concentrate availability and safety are limited by the development of platelet storage lesions (PSLs) and risk of bacterial contamination. Platelet storage lesions are a series of biochemical, structural, and functional changes that occur from blood collection to transfusion. Understanding of PSLs is key for devising interventions that prolong PC shelf life to improve PC access and wastage. This article will review advancements in clinical and mechanistic PSL research. In brief, exposure to artificial surfaces and high centrifugation forces during PC preparation initiate PSLs by causing platelet activation, fragmentation, and biochemical release. During room temperature storage, enhanced glycolysis and reduced mitochondrial function lead to glucose depletion, lactate accumulation, and product acidification. Impaired adenosine triphosphate generation reduces platelet capacity to perform energetically demanding processes such as hypotonic stress responses and activation/aggregation. Storage-induced alterations in platelet surface proteins such as thrombin receptors and glycoproteins decrease platelet aggregation. During storage, there is an accumulation of immunoactive proteins such as leukocyte-derive cytokines (tumor necrosis factor α, interleukin (IL) 1α, IL-6, IL-8) and soluble CD40 ligand which can participate in transfusion-related acute lung injury and nonhemolytic transfusion reactions. Storage-induced microparticles have been linked to enhanced platelet aggregation and immune system modulation. Clinically, stored PCs have been correlated with reduced corrected count increment, posttransfusion platelet recovery, and survival across multiple meta-analyses. Fresh PC transfusions have been associated with superior platelet function in vivo; however, these differences were abrogated after a period of circulation. There is currently insufficient evidence to discern the effect of PSLs on transfusion safety. Various bag and storage media changes have been proposed to reduce glycolysis and platelet activation during room temperature storage. Moreover, cryopreservation and cold storage have been proposed as potential methods to prolong PC shelf life by reducing platelet metabolism and bacterial proliferation. However, further work is required to elucidate and manage the PSLs specific to these storage protocols before its implementation in blood banks.

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.

Transfusion reactions after transfusion of platelets stored in PAS-B, PAS-C, or plasma: a nationwide comparison

BACKGROUND

Platelets (PLTs) stored in PLT additive solution (PAS) are associated with fewer allergic reactions than plasma-stored PLTs. However, earlier studies could not provide conclusive evidence on febrile reactions and did not analyze other transfusion reactions separately due to limited sample size. We therefore compared incidences of all transfusion reactions of PAS-B-PLTs, PAS-C-PLTs, and plasma-PLTs.

STUDY DESIGN AND METHODS

In this observational study, all transfusion reactions reported to the national hemovigilance office of the Netherlands from 2006 to 2015 were included.

RESULTS

During the study period, a total of 2407 transfusion reactions after PLT transfusions were reported. In that period 553,267 pooled buffy coat-derived PLT units were issued, of which 83,884 were stored in PAS-B, 45,728 in PAS-C, and 423,655 in plasma. Regarding transfusion-related circulatory overload, transfusion-related acute lung injury, and "other reactions" no significant differences were observed between the PLT products. When PAS-B-PLT transfusions were compared to plasma-PLT transfusions, the overall relative risk (RR; 95% confidence interval [CI]) of transfusion reactions was 0.99 (0.88-1.11); for allergic and febrile nonhemolytic transfusion reactions (FNHTRs) it was 0.66 (0.55-0.80) and 1.54 (1.27-1.86), respectively. When PAS-C-PLTs were compared to plasma-PLTs, the RR (95% CI) was 0.56 (0.46-0.68) for all transfusion reactions, 0.38 (0.28-0.52) for allergic reactions, and 0.82 (0.59-1.13) for FNHTRs. When PAS-C-PLTs were compared to PAS-B-PLTs, for all reactions the RR (95% CI) was 0.56 (0.45-0.70) for allergic reactions 0.58 (0.40-0.82), and for FNHTRs 0.53 (0.37-0.75).

CONCLUSIONS

PAS-C-PLTs are associated with fewer transfusion reactions compared to plasma-PLTs and compared to PAS-B-PLTs.

Acid sphingomyelinase mediates murine acute lung injury following transfusion of aged platelets

Pulmonary complications from stored blood products are the leading cause of mortality related to transfusion. Transfusion-related acute lung injury is mediated by antibodies or bioactive mediators, yet underlying mechanisms are incompletely understood. Sphingolipids such as ceramide regulate lung injury, and their composition changes as a function of time in stored blood. Here, we tested the hypothesis that aged platelets may induce lung injury via a sphingolipid-mediated mechanism. To assess this hypothesis, a two-hit mouse model was devised. Recipient mice were treated with 2 mg/kg intraperitoneal lipopolysaccharide (priming) 2 h before transfusion of 10 ml/kg stored (1–5 days) platelets treated with or without addition of acid sphingomyelinase inhibitor ARC39 or platelets from acid sphingomyelinase-deficient mice, which both reduce ceramide formation. Transfused mice were examined for signs of pulmonary neutrophil accumulation, endothelial barrier dysfunction, and histological evidence of lung injury. Sphingolipid profiles in stored platelets were analyzed by mass spectrophotometry. Transfusion of aged platelets into primed mice induced characteristic features of lung injury, which increased in severity as a function of storage time. Ceramide accumulated in platelets during storage, but this was attenuated by ARC39 or in acid sphingomyelinase-deficient platelets. Compared with wild-type platelets, transfusion of ARC39-treated or acid sphingomyelinase-deficient aged platelets alleviated lung injury. Aged platelets elicit lung injury in primed recipient mice, which can be alleviated by pharmacological inhibition or genetic deletion of acid sphingomyelinase. Interventions targeting sphingolipid formation represent a promising strategy to increase the safety and longevity of stored blood products.

Antibodies against human platelet alloantigens and human leucocyte antigen class 1 in Saudi Arabian multiparous women and multi-transfused patients

OBJECTIVES

To determine the frequency of alloimmunization against human platelet antigens (HPAs) and human leucocyte antigen class 1 (HLA1) in multiparous women and multi-transfused patients.  

METHODS

This prospective study was conducted between January and August 2013, on 50 multiparous women with no history of previous blood transfusion recruited from the Obstetrics and Gynecology Clinic, and 50 patients, who received multiple platelet transfusions, recruited from the Hematology/Oncology Ward, King Khalid University Hospital, Riyadh, Saudi Arabia.

RESULTS

The frequency of alloimmunization among multiparous pregnant women was 76%, as follows: 16% against HLA1 only, 8% against HPAs only, 52% against both HPAs and HLA1 antigens. In multi-transfused patients, the rate of alloimmunization was 42% as follows: 2% against HLA1 only, 22% against HPAs only, 18% against both HPAs and HLA1 antigens. The frequency of alloimmunization increases with the number of pregnancies, but not with the number of platelet transfusions.

CONCLUSION

Alloimmunization against HPAs and HLA1 is very common among Saudi multiparous women and multi-transfused patients, which encourages the search for the extent of the possible complications in the fetus and newborn and in multitransfused patients and how to prevent their occurrence.

Influence of Oxidative Stress on Stored Platelets

Platelet storage and its availability for transfusion are limited to 5-6 days. Oxidative stress (OS) is one of the causes for reduced efficacy and shelf-life of platelets. The studies on platelet storage have focused on improving the storage conditions by altering platelet storage solutions, temperature, and materials. Nevertheless, the role of OS on platelet survival during storage is still unclear. Hence, this study was conducted to investigate the influence of storage on platelets. Platelets were stored for 12 days at 22°C. OS markers such as aggregation, superoxides, reactive oxygen species, glucose, pH, lipid peroxidation, protein oxidation, and antioxidant enzymes were assessed. OS increased during storage as indicated by increments in aggregation, superoxides, pH, conjugate dienes, and superoxide dismutase and decrements in glucose and catalase. Thus, platelets could endure OS till 6 days during storage, due to the antioxidant defense system. An evident increase in OS was observed from day 8 of storage, which can diminish the platelet efficacy. The present study provides an insight into the gradual changes occurring during platelet storage. This lays the foundation towards new possibilities of employing various antioxidants as additives in storage solutions.

Hemostatic function and transfusion efficacy of apheresis platelet concentrates treated with gamma irradiation in use for thrombocytopenic patients

BACKGROUND

During the transfusion of blood components, the transfer of allogeneic donor white blood cells (WBCs) can mediate transfusion-associated graft-versus-host disease (TA-GVHD). To minimize the reaction, exposure of blood products to gamma irradiation is currently the standard of care. The aim of our study was to evaluate and compare hemostatic function, transfusion efficacy, and safety of gamma-irradiated single-donor apheresis platelet concentrates (PCs) and of conventional non-irradiated PCs in patients with chemotherapy-induced thrombocytopenia.

METHODS

20 double-dose single-donor leukoreduced PCs were split in two identical units; one was gamma-irradiated with 25 Gy (study arm A) and the other remains non-irradiated (study arm B). Both units were stored under equal conditions. Hematologic patients were randomly assigned to receive gamma-irradiated or conventional non-irradiated PCs. Hemostatic function was evaluated by thrombelastography (TEG). TEG measurements were taken pre transfusion and 1 and 24 h post transfusion. TEG profiles were measured, noting the time to initiate clotting (R), the angle of clot formation (α), and the maximum amplitude (clot strength (MA)). Whole blood samples were collected from these thrombocytopenic patients at 1 and 24 h for PLT count increments (CIs) and corrected count increments (CCIs) with assessments of transfusion efficacy. Time to next PLT transfusion, transfusion requirement of RBCs, active bleeding, and adverse events (AEs), were analyzed.

RESULTS

No differences could be found in hemostatic function parameters (MA, R, and α) between study arms A and B (all p values > 0.096) pre transfusion as well as 1 and 24 h post transfusion. No differences between study arms A and B were observed for mean (± standard deviation (SD)) 1-hour CCI (12.83 ± 6.33 vs. 11.59 ± 5.97) and 24-hour CCI (6.56 ± 4.10 vs. 5.76 ± 4.05). Mean 1-hour CI and 24-hour CI were not significantly different in both study arms (p = 0.254 and p = 0.242 respectively). Median time to the next PC transfusion after study PC was not significantly different between groups: (2.4 vs. 2.2 days, p = 0.767). No differences could be found in transfusion requirement of red blood cells (p = 0.744) between both study arms. There were also no regarding bleeding, adverse events, and acute transfusion reaction(s).

CONCLUSIONS

This study confirms safety of gamma-irradiated PCs for treatment thrombocytopenia. Hemostatic function, transfusion efficacy, bleeding, and safety of single-donor apheresis PCs treated with gamma irradiation versus untreated control PCs are comparable.

Removal of biological response modifiers associated with platelet transfusion reactions by columns containing adsorption beads

BACKGROUND

Biological response modifiers (BRMs), such as soluble CD40 ligand (sCD40L); regulated upon activation, normal T-cell expressed, and secreted (RANTES); and transforming growth factor-β1 (TGF-β1), are released from platelets (PLTs) during storage and may trigger adverse effects after PLT transfusion. Although washing PLTs is effective at reducing the level of BRMs and the incidence of transfusion reactions, the washing procedure is time-consuming and may induce PLT activation. Furthermore, some BRMs continue to accumulate during the storage of washed PLTs. A method to remove BRMs using adsorbent columns has not yet been developed.

STUDY DESIGN AND METHODS

We evaluated the ability of columns packed with Selesorb and Liposorber beads, which are both clinically used, to remove BRMs from PLT concentrates (PCs) stored for 5 days. The levels of these BRMs were determined before and after adsorption.

RESULTS

The adsorption columns significantly reduced the levels of RANTES and sCD40L and partially reduced TGF-β1. There were no significant effects on PLT activation, aggregation, morphology, and plasma lactate dehydrogenase (an indicator of PLT lysis) levels, or hypotonic shock response. Adsorption, however, reduced the PLT recovery to approximately 60% of the untreated value.

CONCLUSIONS

This study showed that the levels of BRMs were substantially reduced using columns of clinically available adsorption beads. PLT functions and the quality of PCs were maintained after adsorption. The use of adsorption columns may be useful in reducing the incidence of nonhemolytic transfusion reactions.

The impact of platelet additive solution apheresis platelets on allergic transfusion reactions and corrected count increment (CME)

BACKGROUND

Allergic transfusion reaction (ATR) incidence ranges from 1% to 3% of all transfusions. We evaluated the impact of InterSol platelet additive solution (PAS) apheresis platelets (APs) on the incidence of ATRs and the posttransfusion platelet (PLT) increment.

STUDY DESIGN AND METHODS

This retrospective study evaluated all ATRs among patients at a university hospital that maintained a mixed inventory of PAS APs and non-PAS APs (standard plasma-suspended PLTs). Corrected count increments (CCIs) were calculated for AP transfusions of individuals who received both a PAS and a non-PAS AP transfusion within a 7-day period. Hypothesis testing was performed with chi-square test for dichotomous variables and t tests for continuous variables.

RESULTS

The incidence of ATRs among the non-PAS APs was 1.85% (72 ATRs/3884 transfusions) and 1.01% (12 ATRs/1194 transfusions) for PAS APs (risk ratio [RR], 0.54; 95% confidence interval [CI]=0.30-0.99; p=0.04). However, there was no difference in the incidence of febrile nonhemolytic transfusion reactions between non-PAS APs (incidence, 0.70%; 27/3884) compared to PAS APs (incidence, 0.59%; 7/1194; p=0.69). Among 223 individuals with paired non-PAS and PAS AP transfusions, the mean CCI at 1 to 4 hours after transfusion was 4932 (95% CI, 4452-5412) for non-PAS APs and was lower for PAS APs (CCI, 3766; 95% CI, 3375-4158; p ≤ 0.001). However, there was no significant difference in mean CCI at 12 to 24 hours between non-PAS (CCI, 2135; 95% CI, 1696-2573) and PAS APs (CCI, 1745; 95% CI, 1272-2217; p=0.14).

CONCLUSIONS

PAS APs substantially reduce the number of ATRs. CCIs for PAS APs were lower immediately after transfusion, but not significantly different at 12 to 24 hours.

Platelet antibody detection by flow cytometry: an effective method to evaluate and give transfusional support in platelet refractoriness

Background

Immune platelet refractoriness is mainly caused by human leukocyte antigen antibodies (80-90% of cases) and, to a lesser extent, by human platelet antigen antibodies. Refractoriness can be diagnosed by laboratory tests and patients should receive compatible platelet transfusions. A fast, effective and low cost antibody-screening method which detects platelet human leukocyte/platelet antigen antibodies is essential in the management of immune platelet refractoriness.

Objective

The aim of this study was to evaluate the efficiency of the flow cytometry platelet immunofluorescence test to screen for immune platelet refractoriness.

Methods

A group of prospective hematologic patients with clinically suspected platelet refractoriness treated in a referral center in Campinas, SP during July 2006 and July 2011 was enrolled in this study. Platelet antibodies were screened using the flow cytometry platelet immunofluorescence test. Anti-human leukocyte antigen antibodies were detected by commercially available methods. The sensitivity, specificity and predictive values of the immunofluorescence test were determined taking into account that the majority of antiplatelet antibodies presented human leukocyte antigen specificity.

Results

Seventy-six samples from 32 female and 38 male patients with a median age of 43.5 years (range: 5-84 years) were analyzed. The sensitivity of the test was 86.11% and specificity 75.00% with a positive predictive value of 75.61% and a negative predictive value of 85.71%. The accuracy of the method was 80.26%.

Conclusion

This study shows that the flow cytometry platelet immunofluorescence test has a high correlation with the anti-human leukocyte antigen antibodies. Despite a few limitations, the method seems to be efficient, fast and feasible as the initial screening for platelet antibody detection and a useful tool to crossmatch platelets for the transfusional support of patients with immune platelet refractoriness.

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.

The cost-effectiveness of platelet additive solution to prevent allergic transfusion reactions

BACKGROUND

Allergic transfusion reactions (ATRs) are among the most common complications of transfusion. Storage in platelet additive solution (PAS) has been shown to reduce ATRs from apheresis platelets (APs). This study evaluated the cost-effectiveness of using PAS storage as an alternative method to reduce ATRs.

STUDY DESIGN AND METHODS

A Markov-based decision tree was constructed to compare ATR rates and associated costs expected from current practice and from alternative strategies of using APs stored in PAS. The potential use of pretransfusion medication was also incorporated. Using a hospital perspective and including direct medical expenses only (US$2012), Monte Carlo microsimulations were run to evaluate outcomes under a base-case analysis. One-way and probabilistic sensitivity analyses were used to assess outcome uncertainty.

RESULTS

Under base-case variables, using APs stored in PAS for all patients as an initial transfusion protocol is expected to avert ATRs and associated costs, compared to current practice. Using PAS for all patients along with pretransfusion medication would be cost-saving only when the additional cost of PAS is below $9.14. If PAS storage could eliminate pretransfusion medication use, it is expected to result in cost savings when the additional unit cost of PAS is under $11.90. At a PAS cost of $15, averting one ATR would cost $701.95. Using PAS storage only in response to recurring mild ATRs is associated with cost savings under all costs of PAS evaluated.

CONCLUSIONS

Using PAS storage for all AP transfusions to prevent ATRs may be financially and clinically beneficial, compared to current practice.

The observation of bleeding complications in haemato-oncological patients: stringent watching, relevant reporting

BACKGROUND

The reported percentage of haemato-oncological patients experiencing bleeding complications is highly variable, ranging from 5 to 70%, posing a major problem for comparison of clinical platelet transfusion trials using bleeding complications as a primary endpoint. In a pilot study we assessed the impact of the design of scoring of bleeding on the percentage of patients with WHO grade 2 or higher bleeding grades.

STUDY DESIGN AND METHODS

We performed a prospective, observational study using a rigorous bleeding observation system in thrombocytopenic patients with haemato-oncological disorders. Endpoints of the study were the percentage of patients and days with bleeding WHO grade ≥ 2 comparing designs in which skin bleeding represent a continuation of a previous bleed or a new bleed.

RESULTS

In four participating hospitals 64 patients suffering 870 evaluable thrombocytopenic days (platelet count < 80 × 10(9) L(-1)) were included. At least one episode of bleeding grade ≥ 2 occurred in 36 patients (56%). Most grade 2 bleeding complications occurred mucocutaneously. The percentage of days with bleeding of grade ≥ 2 was 16% but decreases to 8% when only newly developed skin bleeding was included.

CONCLUSION

Rigorous daily observation results in a bleeding incidence that is comparable to recent reportings applying the same method. The results of this study show that censoring for stable skin bleeding has a profound effect on bleeding incidence per day. The clinical relevance of rigorous or clinically judged bleeding scores as an endpoint remains to be defined.

ABO antibody titers are not predictive of hemolytic reactions due to plasma-incompatible platelet transfusions

BACKGROUND

The overall risk of hemolytic transfusion reactions (HTRs) from plasma (minor)-incompatible platelet (PLT) transfusions and the role of a critical anti-A or anti-B titer in predicting and preventing these reactions has not been clearly established.

STUDY DESIGN AND METHODS

We evaluated all apheresis PLT (AP) transfusions for 3 months. Using the gel titer method, we determined the anti-A and/or the anti-B immunoglobulin (Ig)G titer for all incompatible APs. Reported febrile transfusion reactions and HTRs were recorded; transfusions were not prospectively evaluated by the study team. A posttransfusion direct antiglobulin test (DAT) and eluate were performed after a reported febrile or hemolytic reaction for patients who received plasma-incompatible APs.

RESULTS

A total of 647 of 4288 AP transfusions (15.1%) were plasma incompatible. Group O APs (n = 278) had significantly higher anti-A and anti-B titers than group A or B APs (p < 0.0001). No group A or B APs had a titer of more than 128 (0/342). For group O APs, 73 had titers of 256 or greater (26.3%), and 27 had titers of 512 or greater (9.7%). No HTRs were reported to any plasma-incompatible AP transfusion during the study period. Two plasma-incompatible AP transfusions were associated with fever and chills and positive DATs, of which one had a positive eluate. The incidence of a DAT and eluate-positive febrile transfusion reaction in the plasma-incompatible AP population is 0.15% (95% confidence interval, 0.0%-0.86%).

CONCLUSION

A critical anti-A or -B titer is not sufficient to predict the risk of hemolysis in patients receiving plasma-incompatible APs, although underreporting of reactions to the blood bank may limit the generalizability of this study.

Scratching the surface of allergic transfusion reactions

Allergic transfusion reactions (ATRs) are a spectrum of hypersensitivity reactions that are the most common adverse reaction to platelets and plasma, occurring in up to 2% of transfusions. Despite the ubiquity of these reactions, little is known about their mechanism. In a small subset of severe reactions, specific antibody has been implicated as causal, although this mechanism does not explain all ATRs. Evidence suggests that donor, product, and recipient factors are involved, and it is possible that many ATRs are multifactorial. Further understanding of the mechanisms of ATRs is necessary so that rationally designed and cost-effective prevention measures can be developed.

The role of bicarbonate in platelet additive solution for apheresis platelet concentrates stored with low residual plasma

BACKGROUND

Complex platelet additive solutions (PASs) are required to store platelet (PLT) concentrates with plasma levels below 30%. Previously, apheresis PLTs stored with 5% plasma in acetate- and bicarbonate-containing PAS maintained stable pH and bicarbonate levels during 7-day storage. Due to this observation, the necessity of added bicarbonate in PAS was investigated and whether the concurrent increase in PAS pH after bicarbonate addition had any effect on PLT storage.

STUDY DESIGN AND METHODS

Apheresis PLTs were stored in 5% plasma-95% high- or low-pH PAS, with or without bicarbonate (n=10 per arm). Bicarbonate PAS PLTs were paired and nonbicarbonate PAS PLTs were paired (split from same double-dose collection). PLTs were evaluated for in vitro variables on Days 1 and 7 and up to Day 14 if the Day 7 pH was higher than 6.2.

RESULTS

PLT pH was maintained above 7.3 to Day 14 in bicarbonate PAS PLTs while pH failures below 6.2 were observed in 4 of 10 and 2 of 10 units on Day 7 in low- and high-pH nonbicarbonate PAS arms, respectively. Day 7 in vitro variables in nonbicarbonate PAS PLTs with pH values of higher than 6.2 were comparable to Day 7 variables in bicarbonate PAS PLTs. The pH of bicarbonate PAS did have a small effect on pH and bicarbonate levels in PLT units, but did not have an effect on functional variables and metabolism.

CONCLUSION

Bicarbonate was not required to maintain in vitro PLT function in 5% plasma-95% PAS, but was required as a pH buffer and increased PAS pH did not significantly contribute to this effect.

Evaluation of the performance of Trima Accel® v5.2 for the collection of concentrated high-dose platelet products and concurrent plasma from high platelet count donors, in Germany

BACKGROUND AND OBJECTIVES

This study was undertaken to test the ability of Trima Accel® version 5.2 to simultaneously collect concentrated high-dose leukoreduced platelet products and double doses of plasma.

MATERIALS AND METHODS

Random volunteers (18-65 years of age) with preprocedure platelet counts above 270 × 10(3) /μl were recruited among the blood center's apheresis donors. All complied with the center's donor selection criteria.

RESULTS

One hundred fourteen (114) collections were performed. Depending on which definition of single platelet dose is used (2.0 × 10(11) as prevalent standard in most European countries, and 3.0 × 10(11) as prevalent standard in the United States and Canada) in 107/114 (single dose = 2.0 × 10(11) ) and 39/114 (single dose = 3.0 × 10(11) ) instances, a triple platelet product was obtained. In 87 cases (76%), a double plasmaproduct (>430 ml) was collected, and in seven cases (6%), a single plasma product (>220 ml) was collected. In 20 procedures, only platelets without concurrent plasma were collected (18%). Overall procedure time was 87 ± 13 min and average platelet yield per procedure was 8.5 ± 1.4 × 10(11) (final storage concentration, 1,279 ± 153 × 10(3) /μl). The median residual leukocyte content per transfusion dose was 0.13 × 10(6) (0.02-0.98 × 10(6) ) for a single dose of 2.0 × 10(11) and 0.14 × 10(6) (0.02-0.98 × 10(6) ) for a single dose of 3.0 × 10(11) .

CONCLUSIONS

Trima Accel® version 5.2 allows for collection of concentrated high yield platelet products. It offers high productivity and reliably achieves the configured yield targets. Leukoreduction performance complied with both US and EU legal requirements. Collection as hyperconcentrates furthermore allowed for concurrent collection of double dose plasma in the majority of the procedures.

Current status of additive solutions for platelets

The storage of platelets in additive solution (PAS) had lagged behind red cell concentrates, especially in North America. The partial or complete removal of anticoagulated plasma and storage of platelet concentrates in AS presents many advantages. The PAS can be formulated to optimize aerobic metabolism or decrease platelet activation, thus abrogating the platelet storage lesion and potentially improving in vivo viability. Plasma removal has been shown to reduce allergic reactions and the plasma harvested could contribute to the available plasma pool for transfusion or fractionation. PAS coupled to pathogen reduction technology results in a platelet product of equivalent hemostatic efficacy to conventionally stored platelets. Given the above, the likely future direction of platelet storage will be in new generation designer PAS with an extended shelf life and a superior safety profile to plasma stored platelets. J. Clin. Apheresis, 2012. © 2012 Wiley Periodicals, Inc.

The impact of apheresis platelet manipulation on corrected count increment

BACKGROUND

Concentrating and washing apheresis platelets (APs) substantially reduce the number of allergic transfusion reactions likely due to removal of plasma. However, these processes may damage platelets (PLTs). This study evaluated whether concentrating or washing APs decrease the corrected count increment (CCI).

STUDY DESIGN AND METHODS

This retrospective study evaluated individuals who initially received unmanipulated APs and subsequently received concentrated and/or washed APs at a large university hospital between 1998 and 2009. Concentrated units were prepared by reducing the plasma volume of APs by a goal of more than 67%. Washed units were prepared by washing the APs with 1 L of normal saline. The CCI (PLTs [×10(6)] × m(2)/L) for all transfusions was calculated. Hypothesis testing was performed with t tests for continuous variables and chi-square tests for dichotomous variables.

RESULTS

We evaluated 121 individuals: 46 patients who received unmanipulated, concentrated, and then washed APs; 59 patients who received unmanipulated and then concentrated APs; and 16 patients who received unmanipulated and then washed APs. Patient demographics were similar among the three groups. The mean CCI for unmanipulated AP transfusions at 0 to 2 hours posttransfusion was significantly higher than concentrated and washed PLT transfusions (p<0.001). When accounting for PLT loss due to manipulation, concentrating APs did not impact the CCI. However, the CCI remained significantly lower for washed products at all time points after transfusion (40.7% mean reduction at 20-24 hr, p<0.001).

CONCLUSIONS

Washing APs significantly reduces PLT count recovery and survival, as demonstrated by a significantly reduced CCI.

Comparative in vitro evaluation of apheresis platelets stored with 100% plasma or 65% platelet additive solution III/35% plasma and including periods without agitation under simulated shipping conditions

BACKGROUND

A comparative study evaluated the retention of apheresis platelet (A-PLT) in vitro properties prepared with PLT additive solution (PAS)-III or 100% plasma and stored with continuous agitation (CA) and without continuous agitation (WCA).

STUDY DESIGN AND METHODS

PLTs collected with the Amicus cell separator (Fenwal, Inc.) were utilized to prepare two matched components, each with approximately 4 × 10(11) PLTs. In the primary study, one component contained 65% PAS-III/35% plasma and the other 100% plasma. Four storage scenarios were used, one with CA and three with periods without agitation under simulated shipping conditions. In vitro assays were used early and after 5 days of storage.

RESULTS

pH levels after 5 days with CA were less with PAS-III components than 100% plasma components, with levels always above 6.6 in any component. With CA, a number of other variables were reduced even early during storage with PAS-III including morphology, extent of shape change, hypotonic stress response, adhesion, and aggregation. Storage WCA resulted in only a limited increase in the magnitude of the assay differences between PAS-III and 100% plasma components. Periods WCA did not reduce the pH below 6.6. The thromboelastograph variable associated with the strengthening of clots by PLTs was essentially comparable with PAS-III and plasma components throughout storage with CA or WCA.

CONCLUSION

The data indicate that a 100% plasma medium provides for better retention of specific in vitro PLT properties, with CA and WCA, although the clinical significance of these in vitro decrements due to PAS-III is unknown.

Meta-analysis of the studies of bleeding complications of platelets pathogen-reduced with the Intercept system

BACKGROUND

The eligibility criteria of a previously reported meta-analysis (Transfusion 2011;51:1058-1071) of randomized controlled trials (RCTs) of pathogen reduction of platelets in patients with hypoproliferative thrombocytopenia were modified to examine the impact on the findings of: (1) inclusion of a (previously excluded) RCT; (2) restriction of eligibility to RCTs of the Intercept (amotosalen-HCl/ultraviolet-A-light) system; and (3) differences in the methods used to assess bleeding complications.

MATERIALS AND METHODS

Five RCTs comparing the risk of all, clinically significant (grades 2 through 4) and/or severe (grades 3 and 4) bleeding complications between recipients of platelets treated with Intercept vs. standard unmanipulated platelets were included. Odds ratios (ORs) of bleeding complications of similar severity recorded during similar periods of observation were calculated across all studies and across homogeneous subsets of studies by random-effects methods.

RESULTS

Treatment with Intercept increased all bleeding complications when four RCTs meeting the eligibility criteria of the previous meta-analysis were integrated, but not across all the five currently available studies [summary OR=1·24; 95% confidence interval (CI), 0·79-1·93]. Clinically significant bleeding complications increased when the results of the SPRINT RCT were based on the expanded safety analysis (summary OR=1·52; 95% CI, 1·09-2·12)--but not the initial report (summary OR=1·30; 95% CI, 0·54-3·14)--of that study.

CONCLUSIONS

Treatment with Intercept may increase the risk of all and clinically significant (albeit not severe) bleeding complications in RCTs maintaining a platelet count of ≥10×10(9) or ≥20×10(9)/l through increased platelet transfusions.