Universal adoption of pathogen inactivation of platelet components: impact on platelet and red blood cell component use

BACKGROUND: Pathogen inactivation of platelet (PLT) components (INTERCEPT Blood System, Cerus Europe) was implemented into routine practice at a blood center supporting a tertiary care hospital. Utilization of platelet components (PCs) and red blood cell (RBC) components was analyzed for 3 years before and 3 years after introduction of pathogen inactivation to assess the impact of pathogen inactivation on component use.
STUDY DESIGN AND METHODS: This was a retrospective analysis of prospectively collected data. An electronic database used in routine blood bank hemovigilance to monitor production and use of blood components was analyzed to assess clinical outcomes.
RESULTS: Transfusion records were analyzed for 688 patients supported with conventional PCs and 795 patients supported with pathogen inactivation PCs. Additional analyses were conducted for intensively transfused hematology patients. Patient demographics (age category, sex, and diagnostic category) were not different in the two observation periods. For all patients, mean numbers of PC per patient were not different for conventional PCs and pathogen inactivation PCs (9.9 ± 19.5 vs. 10.1 ± 20.9, p = 0.88). Data for hematology patients (272 conventional PCs and 276 pathogen inactivation PCs) confirmed that days of PLT support were not different (31.6 ± 42.6 vs. 33.1 ± 47.9, p = 0.70) nor was total PLT dose (10¹¹) per patient (87.3 ± 115.4 vs. 88.1 ± 111.6, p = 0.93). RBC use, for all patients and hematology patients, was not different in the two observation periods, either during periods of PLT support or outside periods of PLT transfusion support.
CONCLUSION: Pathogen inactivation of PCs had no adverse impact on component use during a 3-year observation period of routine practice.     

Allergic agonists in apheresis platelet products are associated with allergic transfusion reactions

BACKGROUND: The mechanisms that underlie allergic transfusion reactions (ATRs) are not well characterized, but likely involve recipient, donor, and product factors. To assess product factors associated with ATRs, we investigated candidate mediators in apheresis platelet (PLT) products associated with ATRs and controls. STUDY DESIGN AND METHODS: Using bead‐based and standard enzyme‐linked immunosorbent assays, we tested supernatants from 20 consecutive apheresis PLT transfusions associated with ATRs and 30 control products for concentrations of mediators in three categories: acute inflammatory mediators, direct agonists of basophils and mast cells, and growth and/or priming factors of basophils and mast cells. RESULTS: Median concentrations of the direct allergic agonists C5a, brain‐derived neurotrophic factor (BDNF), and CCL5 (RANTES) were 16.6, 41.8, and 13.9% higher, respectively, in the supernatant of apheresis PLT products that were most strongly associated with ATRs (p < 0.05 for each mediator). Other direct agonists (macrophage inflammatory protein‐1α, monocyte chemotactic protein‐1, eotaxin‐1, interleukin‐8) were similar between groups. Concentrations of acute inflammatory mediators and basophil growth and/or priming factors were also similar between groups (p > 0.2 for all associations). CONCLUSION: The allergic agonists C5a, BDNF, and CCL5 may be mediators of ATRs in apheresis PLT products. Acute inflammatory proteins and basophil and/or mast cell growth and priming factors do not appear to be associated with apheresis PLT products that cause ATRs.     

Use of additive solutions and pathogen inactivation treatment of platelet components in a regional blood center: impact on patient outcomes and component utilization during a 3‐year period

BACKGROUND: The Etablissement Français du Sang Alsace (EFS Alsace) successively implemented universal use of platelet additive solutions (PASs) and pathogen inactivation (PI) for platelet components (PCs). To assess the impact of these changes, EFS Alsace evaluated PC use, red blood cell (RBC) component use, and transfusion‐related adverse events after implementation of these new technologies. STUDY DESIGN AND METHODS: EFS Alsace prospectively collects data on production, distribution, and response to transfusion of all blood components with greater than 99.5% data acquisition. Adverse events attributed to platelet (PLT) transfusions were collected through a mandatory, active hemovigilance program. A retrospective review of prospectively collected data was conducted covering three periods: 1) apheresis and whole blood–derived PCs in plasma, 2) apheresis and whole blood–derived PCs with PAS, and 3) PCs prepared with PI and PAS. Data on component utilization were analyzed for all patients receiving PCs in each period and for the subset of hematology‐oncology patients to evaluate PC use in an intensely transfused population. Values for all continuous variables were summarized as mean and standard deviation, median, and range. RESULTS: Approximately 2000 patients received PCs in each period. PLT and RBC use per patient was not increased after PI (analysis of variance, F = 1.9 and 2.9, respectively) and the incidence of acute transfusion reactions was significantly reduced (p < 0.001). CONCLUSIONS: Universal use of PI was implemented without impacting component use, as indicated by total dose of PLTs per patient, and outcomes to transfusion were improved.     

Atopic predisposition of recipients in allergic transfusion reactions to apheresis platelets

BACKGROUND: The biologic mechanisms of allergic transfusion reactions (ATRs) are largely unknown. We sought to compare the atopic predisposition of platelet (PLT) recipients who experienced an ATR to nonreactive control recipients. STUDY DESIGN AND METHODS: We identified 37 consecutive apheresis PLT recipients who experienced an ATR and 26 matched controls. Total immunoglobulin (Ig)E and aero‐ and food allergen–specific IgE were quantified in plasma by a blood test for allergies (ImmunoCAP: Phadiatop and Fx5). IgE testing of apheresis PLT supernatants was also performed. RESULTS: Pruritus and urticaria were manifest in 91.9 and 83.8% of all ATRs, with more severe respiratory symptoms and angioedema occurring in less than 15% of cases. No subject had anaphylaxis. Sex, age, and primary diagnosis were balanced between the two groups. Total and aeroallergen‐specific IgE was higher among subjects experiencing an ATR in comparison to control subjects (median total IgE, 55.5 kU/L vs. 8.3 kU/L, p = 0.002; and median aeroallergen‐specific IgE, 0.57 kUa/L vs. 0.36 kUa/L, p = 0.046). IgE antibody levels in apheresis products associated with ATRs were similar to control products (p > 0.1 for all IgE tests). CONCLUSION: Recipient atopic predisposition, as defined by IgE sensitization, is a risk factor associated with ATRs.     

Frequency and clinical characteristics of allergic transfusion reactions in children

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

Evaluation of antimicrobial peptides as novel bactericidal agents for room temperature–stored platelets

BACKGROUND: A single cost-effective pathogen inactivation approach would help to improve the safety of our nation's blood supply. Several methods and technologies are currently being studied to help reduce bacterial contamination of blood components. There is clearly need for simple and easy-to-use pathogen inactivation techniques specific to plasma, platelets (PLTs), and red blood cells.
STUDY DESIGN AND METHODS: In this report, we introduce a novel proof of concept: using known therapeutic antimicrobial peptides (AMPs) as bactericidal agents for room temperature–stored PLT concentrates (PCs). Nine synthetic AMPs, four from PLT microbicidal protein-derived peptides (PD1-4) and five Arg-Trp (RW) repeat peptides containing one to five repeats, were tested for bactericidal activity in plasma and PC samples spiked with Staphylococcus aureus , S. epidermidis , Escherichia coli , Pseudomonas aeruginosa , Klebsiella pneumoniae, and Bacillus cereus . A 3-log reduction of viable bacteria was considered as the bactericidal activity of a given peptide.
RESULTS: In both plasma alone and PCs, RW3 peptide demonstrated bactericidal activity against S. aureus , S. epidermidis , E. coli , P. aeruginosa, and K. pneumoniae ; PD4 and RW2 against P. aeruginosa ; and RW4 against K. pneumoniae . The activity of each of these four peptides against the remaining bacterial species in the test panel resulted in less than a 3-log reduction in the number of viable bacteria and hence considered ineffective.
CONCLUSIONS: These findings suggest a new approach to improving the safety of blood components, demonstrating the potential usefulness of screening therapeutic AMPs against selected bacteria to identify suitable bactericidal agents for stored plasma, PCs, and other blood products.     

Transfusion-related acute lung injury: reports to the French Hemovigilance Network 2007 through 2008

BACKGROUND: Transfusion‐related acute lung injury (TRALI) is a major cause of transfusion‐related mortality and morbidity. Epidemiologic studies using data from national transfusion schemes can help achieve a better understanding of TRALI incidence. STUDY DESIGN AND METHODS: A multidisciplinary working group analyzed TRALI cases extracted from the French Hemovigilance Network Database (2007‐2008). All notified cases were reviewed for diagnosis. Those meeting the Canadian Consensus Conference criteria for TRALI were classified according to imputability to transfusion and clinical severity. Patient data (clinical characteristics, number and types of products transfused, and serology results) were obtained. RESULTS: There were 62 TRALI cases and 23 possible TRALI cases during the 2‐year period. An immune‐mediated mechanism was identified in 30 of 50 TRALI cases with complete serology. TRALI was considered to be the cause of death in 7.1% of patients and might have contributed to death in an additional 9.4% of TRALI or possible TRALI patients. Occurrence ranked high in obstetrics (15%), after surgery (34%), and in hematologic malignancies (21%). Single‐donor high‐plasma‐volume components were involved in half of the cases where the implicated blood product could be determined and carried the highest risk per component (1:31,000 for single‐donor fresh‐frozen plasma units and apheresis platelet [PLT] concentrates, and 1:173,000 for red blood cells). No incident could be definitively related to the transfusion of solvent/detergent‐treated pooled plasma (>200,000 units transfused), nor to pooled PLT concentrates. CONCLUSION: The proportion of TRALI cases related to plasma‐rich components was lower than previously described.     

Testing platelet mass versus platelet count to guide platelet transfusions in the neonatal intensive care unit

BACKGROUND: Platelet (PLT) transfusions can bestow significant benefits but they also carry risks. This study sought a safe means of reducing PLT transfusions to neonatal intensive care unit (NICU) patients with thrombocytopenia by comparing two transfusion guidelines, one based on PLT count and the other on PLT mass (PLT count times mean PLT volume).
STUDY DESIGN AND METHODS: Using a prospective, two-centered, before versus after design, PLT transfusion usage and hemorrhagic events were contrasted during a period when PLT count–based transfusion guidelines were in use (Period 1) versus a period when PLT mass–based guidelines were in use (Period 2).
RESULTS: No differences were observed between Periods 1 and 2 in NICU admissions, sex, race/ethnicity, percentage of inborn patients, or percentage of patients with a PLT count less than 50 × 10⁹ or 51 × 10⁹ to 99 × 10⁹/L. In the first period 3.6% of NICU admissions received one or more PLT transfusions. This fell to 1.9% during the second period (p < 0.002). The number of PLT transfusions administered per transfused patient was the same in both periods: 2.0 (1-23) (median [range]) in Period 1 and 2.0 (1-17) in Period 2 (p > 0.40). Significantly fewer PLT transfusions were given in Period 2 for prophylaxis (patient not bleeding; p < 0.001 vs. Period 1). The number given for bleeding did not change between the two periods. In Period 2 no increases were seen in rate of intraventricular hemorrhage (IVH); Grade 3 or 4 IVH; or pulmonary, gastrointestinal, or cutaneous bleeding.
CONCLUSIONS: The use of PLT mass–based NICU transfusion guidelines was associated with fewer PLT transfusions and no recognized increase in hemorrhagic problems.     

Clinical safety of platelets photochemically treated with amotosalen HCl and ultraviolet A light for pathogen inactivation: the SPRINT trial

BACKGROUND: A photochemical treatment (PCT) method utilizing a novel psoralen, amotosalen HCl, with ultraviolet A illumination has been developed to inactivate viruses, bacteria, protozoa, and white blood cells in platelet (PLT) concentrates. A randomized, controlled, double-blind, Phase III trial (SPRINT) evaluated hemostatic efficacy and safety of PCT apheresis PLTs compared to untreated conventional (control) apheresis PLTs in 645 thrombocytopenic oncology patients requiring PLT transfusion support. Hemostatic equivalency was demonstrated. The proportion of patients with Grade 2 bleeding was not inferior for PCT PLTs. STUDY DESIGN AND METHODS: To further assess the safety of PCT PLTs, the adverse event (AE) profile of PCT PLTs transfused in the SPRINT trial is reported. Safety assessments included transfusion reactions, AEs, and deaths in patients treated with PCT or control PLTs in the SPRINT trial. RESULTS: A total of 4719 study PLT transfusions were given (2678 PCT and 2041 control). Transfusion reactions were significantly fewer following transfusion of PCT than control PLTs (3.0% vs. 4.1%; p = 0.02). Overall AEs (99.7% PCT vs. 98.2% control), Grade 3 or 4 AEs (79% PCT vs. 79% control), thrombotic AEs (3.8% PCT vs. 3.7% control), and deaths (3.5% PCT vs. 5.2% control) were comparable between treatment groups. Minor hemorrhagic AEs (petechiae [39% PCT vs. 29% control; p < 0.01] and fecal occult blood [33% PCT vs. 25% control; p = 0.03]) and skin rashes (56% PCT vs. 42% control; p < 0.001) were significantly more frequent in the PCT group. CONCLUSION: The overall safety profile of PCT PLTs was comparable to untreated PLTs.     

Allergic transfusion reactions to platelets are associated more with recipient and donor factors than with product attributes

BACKGROUND: Mechanisms of allergic transfusion reactions (ATRs) are not well understood. The aim of this study was to distinguish recipient‐, donor‐, and product‐specific factors associated with ATRs. STUDY DESIGN AND METHODS: We conducted a retrospective cohort study of apheresis platelet (AP) products transfused from April 2000 through March 2010. The concordance rate of ATRs when split AP products were transfused to at least two individuals was compared to the overall ATR rate among all AP products. Per‐person ATR rates also were compared to the overall ATR rate. RESULTS: We observed 1616 ATRs among 93,737 transfusions, for an overall incidence of 1.72% (95% confidence interval [CI], 1.64%‐1.81%). Of the 1616 ATRs, 630 occurred when split AP products were transfused to at least two recipients. Of these 630 AP products, ATRs were observed in at least two different recipients of the same AP collection only 6 of 630 times, for a concordant incidence of 0.95% (95% CI, 0.35%‐2.06%), which is similar to the overall ATR rate (p = 0.17). On an individual level, 30.0% of recipients had ATR rates of more than 5%, and these 30.0% accounted for 62.1% of ATRs. Donors of AP products associated with concordant ATRs donated AP products that had an ATR rate of 5.8% (95% CI, 3.1%‐9.7%), which is higher than the overall ATR rate (p < 0.001). CONCLUSIONS: An observed ATR does not predict an ATR in a different recipient of a split AP product. A minority of platelet recipients accounts for the majority of ATRs. Some donors are strongly associated with ATRs. Consequently, recipient and donor factors are implicated in the mechanism of ATRs.     

Issuing of blood components dispensed in syringes and bar code–based pretransfusion check at the bedside for pediatric patients

BACKGROUND: The pretransfusion check at the bedside is the most critical step for the prevention of mistransfusion in pediatric patients, as well as in adults. The objective of this study was to assess whether a bar code–based patient–blood unit identification system could be applied to the pretransfusion check at the bedside for the issuing of blood dispensed in syringes.
STUDY DESIGN AND METHODS: The issuing of blood components dispensed in syringes and the bar code–based pretransfusion check at the bedside were initiated for pediatric patients in May 2003. The number of blood components transfused to pediatric patients and rate of compliance with electronic bedside verification for blood dispensed in syringes were determined. Several variables in blood samples that were freshly collected, irradiated, split into 20-mL aliquots, and stored in syringes at 4°C were measured.
RESULTS: Between May 2003 and April 2007, a total of 3957 blood components (10% of all transfusions) were administered to pediatric patients without a single mistransfusion, of which 871 (22%) were issued by dispensing in syringes. The compliance rate with electronic bedside verification for blood dispensed in syringes was 99%. The supernatant potassium concentrations and extracellular free hemoglobin in blood samples stored in syringes at 4°C for 24 hours were 14 ± 1.3 mmol/L and less than 0.3 g/L, respectively, and these were considered to be acceptable for transfusion to pediatric patients.
CONCLUSION: The bar code–based identification system that we used was fully applicable to the pretransfusion check at the bedside for blood dispensed in syringes.     

Therapeutic efficacy of platelet transfusion in patients with acute leukemia: an evaluation of methods

BACKGROUND: Clinical effect of platelet (PLT) transfusion is monitored by measures of PLT viability (PLT recovery and survival) and functionality. In this study we evaluate and compare transfusion effect measures in patients with chemotherapy‐induced thrombocytopenia due to treatment of acute leukemia. STUDY DESIGN AND METHODS: Forty transfusions (28 conventional gamma‐irradiated and 12 pathogen‐inactivated photochemical‐treated PLT concentrates [PCs]) were investigated. PC quality was analyzed immediately before transfusion. Samples were collected from thrombocytopenic patients at 1 and 24 hours for PLT increments and thromboelastography (TEG) with assessments of bleeding score and intertransfusion interval (ITI). Data were analyzed by Spearman's correlation. Patient and PC variables influencing the effect of transfusion were analyzed by use of a mixed‐effects model. RESULTS: PLT dose, storage time, and pathogen inactivation correlated with PLT recovery but not with PLT survival (including ITI), TEG, or clinical bleeding. Fever was negatively correlated with PLT survival but did not affect PLT recovery. After 1 and 24 hours, strong correlations were observed within measures of PLT viability and between PLT increment and the TEG value maximal amplitude (MA). Negative correlation was observed between late MA increment and clinical bleeding status after transfusion (r = ?0.494, p = 0.008). PLT count increments did not correlate to clinical bleeding status. CONCLUSIONS: PLT dose and quality of PCs are important for optimal immediate transfusion response, whereas duration of transfusion effect is influenced mainly by patient variables. The TEG value MA correlates with PLT count increments and bleeding, thus reflecting both PLT viability and functionality.     

输液泵用于婴幼儿输血的护理研究

[目的 ]观察输液泵用于婴幼儿输血的效果。 [方法 ]将 40例输血患儿随机分为输液泵组( 2 0例 )和常规组 ( 2 0例 ) ,观察两组输血后血容量恢复情况 ,记录2 0min内的输血量 ,检测输血前后血液成分的变化。 [结果 ]与常规组相比 ,输液泵输血组血容量恢复正常的人数多 ,时间早 ,未发现急性机械性溶血及急性心功能衰竭、急性肺水肿的临床表现 ;实验室检查血液经输液泵后 ,血红蛋白、红细胞计数及形态、血小板无异常改变。 [结论 ]输液泵用于婴幼儿输血抢救治疗效果优于输血器输血。     

Does a febrile reaction to platelets predispose recipients to red blood cell alloimmunization?

BACKGROUND: A variable effect of inflammation on alloimmunization to transfused red blood cells (RBCs) in mice has been recently reported. We investigated whether RBC alloimmunization in humans was affected by transfusion of blood products in temporal proximity to experiencing a febrile transfusion reaction (FTR) to platelets (PLTs), an event predominantly mediated by inflammatory cytokines.
STUDY DESIGN AND METHODS: Blood bank databases were used to identify patients who experienced an FTR or possible FTR to PLTs from August 2000 to March 2008 (FTR group). The control group of patients received a PLT transfusion on randomly selected dates without experiencing an FTR. The "event" was defined as the PLT transfusion that caused the FTR in the FTR group or the index PLT transfusion in the control group. The number of transfused blood products and their proximity to the event were recorded along with other recipient data. The primary endpoint was the rate of RBC alloimmunization between the two groups.
RESULTS: There were 190 recipients in the FTR group and 245 in the control group. Overall, the recipients in the control group were younger and received more blood products on the day of their event and over the subsequent 10 days. The alloimmunization rate among recipients in the FTR group was higher than in the control group (8% vs. 3%, respectively; p = 0.026).
CONCLUSIONS: These preliminary data support our hypothesis that recipient inflammation may affect RBC alloimmunization in humans; however, a more detailed understanding of the pathophysiologic association between inflammation and alloimmunization is required before definitive conclusions can be reached.     

Analysis of transfusion reactions associated with prestorage-pooled platelet components

BACKGROUND: The goal of this study was to assess transfusion reactions arising from prestorage-pooled platelet (PSPP) infusions compared with apheresis single-donor platelets (SDPs) and poststorage-pooled, whole blood–derived random-donor platelets (RDPs).
STUDY DESIGN AND METHODS: Over a span of 18 months, transfusion reaction records of patients receiving platelet (PLT) infusions were retrospectively reviewed at two academic, tertiary care hospitals. Chi-square analysis was used for statistical comparisons; significance was a p value of less than 0.05.
RESULTS: For the two sites, 10,251 prestorage-leukoreduced PLT products were infused including 4731 PSPPs, 3999 SDPs, and 1521 RDPs. Of the total infusions, 0.91% (93/10,251) were associated with a transfusion reaction. The aggregate transfusion reaction rate was 0.89% (42/4731) for PSPPs, 0.75% (30/3999) for SDPs, and 1.38% (21/1521) for RDPs. There were no significant differences in total reaction rate between PSPPs and the other PLT products (p > 0.05). Allergic transfusion reactions were the most common adverse event for PLT products evaluated (63/10,251; 0.61%) and febrile reactions were second most common (27/10,251; 0.26%). There were 2 suspected cases of sepsis (1 associated with PSPP and 1 associated with RDP; both culture negative) and 1 case of volume overload associated with RDP infusion. There were no significant differences in aggregate allergic or febrile reaction rates among the 93 PLT products evaluated (p > 0.05). No reports of transfusion-related acute lung injury or hemolysis were noted.
CONCLUSIONS: No difference in reactions rates was observed among PSPPs and the other PLT products. The transfusion reactions occurring in this population were not dependent on the type of PLT product infused.     

White blood cell inactivation after treatment with riboflavin and ultraviolet light

Functional white blood cells (WBCs) in blood components may be responsible for a number of adverse transfusion effects, including transfusion‐associated graft‐versus‐host disease (TA‐GVHD), alloimmunization, and alloimmune platelet (PLT) refractoriness. TA‐GVHD occurs when functional lymphocytes are transfused into a patient who is unable to mount an immune response to the human leukocyte antigen (HLA) due to HLA compatibility or immunosuppression. Alloantibodies against HLA antigens on donor WBCs and PLTs are the major cause of refractoriness to PLT transfusions in patients receiving repeated blood transfusions. Attempts to reduce these undesirable effects have included leukoreduction filters and gamma irradiation. Studies have shown that exposure of PLT concentrates to riboflavin and light (Mirasol pathogen reduction technology [PRT], CaridianBCT Biotechnologies) causes irreparable modifications of nucleic acids that result in inactivation of a wide range of pathogens as well as inhibition of the immunologic responses mediated by WBCs present in PLT concentrates. This article summarizes these studies and also reports on additional findings from the Trial to Reduce Alloimmunization to Platelets (TRAP) and Mirasol Clinical Evaluation (MIRACLE) trials. Data from in vitro studies and this clinical trial suggest that PRT treatment may be as effective as gamma irradiation in preventing TA‐GVHD and more effective than leukoreduction in preventing alloimmunization.     

BLOOD COMPONENTS: Lack of antibody formation to platelet neoantigens after transfusion of riboflavin and ultraviolet light–treated platelet concentrates

BACKGROUND: Pathogen inactivation technologies provide a potential solution to donor screening and blood testing strategies reducing the risk of transfusion‐transmitted infectious diseases. The Mirasol pathogen reduction technology (PRT) system (CaridianBCT) uses riboflavin and UV light to introduce modifications in nucleic acids, reducing the infectious pathogen load in blood components. This study evaluated serum of patients who received PRT‐treated platelet (PLT) concentrates over a time period of 28 days for the appearance of antibodies to neoantigens on PLTs. STUDY DESIGN AND METHODS: Serum specimens were obtained at study inclusion and at the 28‐day follow‐up visit from patients randomly assigned to receive PRT‐treated PLT concentrates and at study inclusion of control subjects receiving untreated PLTs. PLT samples from untreated and PRT‐treated PLTs were collected. PLT samples for each patient were pooled for the analysis. The presence of antibodies in patient serum to neoantigens was determined with a modified Capture‐P assay. The presence of auto‐ or alloantibodies in specific patient samples was determined with PAKAUTO and PAK 12 techniques. RESULTS: Forty‐four patients receiving PRT‐treated PLTs were evaluated; none of these patients demonstrated antibodies to neoantigens. One patient demonstrated a PLT alloantibody to human PLT antigen (HPA)‐5b and autoreactivity to glycoprotein Ia/IIa, consistent with an alloantibody at the beginning, but not at the end of the study interval. Of 22 patients evaluated in the control group, one alloantibody with HPA‐5b reactivity was detected. CONCLUSION: Patients receiving PRT‐treated PLT concentrates did not demonstrate antibodies to neoantigens, suggesting that neoantigen formation is not a critical side effect of this pathogen reduction process.     

Red blood cell use outside the operating theater: a prospective observational study with modeling of potential blood conservation during severe blood shortages

BACKGROUND: National guidance recommends planning for future blood shortages, but few studies have evaluated how reduced demand could be achieved acutely.
STUDY DESIGN AND METHODS: A trained observer collected data concerning red blood cell (RBC) transfusion events outside the operating theater during 68 hours of blood bank monitoring over 7 weeks. Data were gathered at the patients' bedside from clinical staff and charts. Transfusions were classified according to the presence of bleeding and medical specialty (medical, surgical, other). Hemoglobin (Hb) transfusion triggers, RBCs transfused, and posttransfusion Hb values were collected. Evidence-based scenarios were used to model the potential RBC savings that could be achieved if acute shortages occurred, incorporating ischemic heart disease as a potential decision modifier.
RESULTS: A total of 83 patients received 100 transfusion events, comprising 207 RBC units, during the sampling periods. The relative use of RBC units across specialties was as follows: medical, 74%; surgical, 22%; and other, 4%. For medical and surgical patients, respectively, 31 and 10% of all RBC units were transfused for anemia without evidence of bleeding, and 38 and 12% were transfused for non–life-threatening bleeding. Eight-five percent of all patients who received transfusions had stable vital signs before transfusion. Our model suggested that only 11% of RBCs would be conserved by cancellation of major surgery, whereas 23% to 47% of all RBCs could be conserved by controlling transfusions to medical patients.
CONCLUSION: In institutions with patterns of blood use similar to ours, control of transfusions to medical patients is the most effective response to acute blood shortages.     

Particulate matter phenomenon: adverse event data and the effect of leukofiltration

BACKGROUND: In February 2002, a multiorganizational task force investigated blood center reports of unusual particulate matter (PM) visible in packed red blood cells (RBC). A cohort study assessed increase in adverse events (AEs) related to this phenomenon, as well as the effect of post-leukofiltration (LF) on PM. METHODS: Two blood centers assessed AEs in patients transfused with RBCs having visible PM (classified as normal by-products of RBC preparation), PM RBCs subsequently LF, or RBCs without visible PM, and the effect of LF on PM removal. RESULTS: There was no difference in AEs in patients transfused with PM RBCs with or without LF compared to patients transfused with RBCs without visible PM. Subsequently filtered PM RBCs had acceptable residual WBC counts and median platelet removal of 92%. CONCLUSION: Transfusion of RBCs with visible PM or RBCs subsequently LF does not appear to increase the risk of an AE. LF use on PM RBCs results in the PM removal without adversely affecting filter performance. The lack of evidence of an increase in AE reports does not mean that there is no effect, and there may be a baseline AE rate attributable to PM which has not been thoroughly researched.