Pathogen inactivation techniques

Viral inactivation for pH-sensitive antibody formats such as multi-specific antibodies

Recently developed multi-specific antibody formats enable new therapeutic concepts. Conveniently, formats with an Fc domain allow purification in well-established mAb platform processes. However, due to the structural complexity of the formats, the assembled molecules may be sensitive to extreme pH commonly used for viral inactivation. An alternative to low pH incubation for virus inactivation is the use of a mixture of tri-n-butyl phosphate (TnBP, solvent) and Polysorbate 80 (PS80, detergent). While TnBP is toxic, this combination has a long history of use in the manufacturing of human plasma-derived products that are sensitive to low or high pH incubation. Data are provided demonstrating that the solvent/detergent (S/D) treatment using TnBP and PS80 can be successfully used for pH-sensitive, multi-specific antibody formats in the clarified cell culture fluid (CCCF). A different placement of the S/D within the purification process, namely during the capture by Protein A (PA), has been evaluated. This alternative placement allows effective viral inactivation by S/D while preserving the viral reduction and viral inactivation achieved through the PA step itself, enabling the cumulation of these effects. Furthermore, the process alternative simplifies the liquid handling by reducing the added volumes of the required S/D liquids, thus reducing the amount of toxic TnBP to a minimum. Data are shown demonstrating a complete removal of TnBP and PS80 in the process.

Rapid Pathogen Purge by Photosensitive Arginine-Riboflavin Carbon Dots without Toxicity

Photo-activatable antipathogenic carbon dots (CDs) were prepared by carbonization of citric acid and arginine (Arg) via 3 min microwave treatment for use in the eradication of common microorganisms. Nitrogen-doped Arg CDs were spherical in shape with a size range of 0.5 to 5 nm. The Arg CDs were modified with fluorescent dyes, such as fluorescein sodium salt (FSS, as Arg-FSS) and riboflavin (RBF, as Arg-RBF), to improve antimicrobial potency by enhancing their application in photodynamic therapy. The modified Arg CDs afforded fluorescence emission properties at 520 nm in the green region in addition to excellent blue fluorescence intensity at 420 nm under 345 nm excitation upon their FSS and RBF conjugation, respectively. Although the cytotoxicity of Arg CDs was decreased for Arg-RBF CDs to 91.2 ± 0.7% cell viability for fibroblasts, the Arg-based CDs could be safely used for intravenous applications at 1000 μg/mL concentration. The Arg CDs showed broad-spectrum antimicrobial activity against common pathogens and the minimum inhibitory concentration of Arg CDs was almost two-fold decreased for the modified forms without UV light. However, faster and more effective antibacterial activity was determined for photosensitive Arg-RBF CDs, with total bacterial eradication upon UV-A light exposure for 30 min.

Human leukocyte antigen alloimmunization prevention mechanisms in blood transfusion

In many fields of clinical medicine and blood transfusion, the human leukocyte antigen (HLA) system is crucial. Alloimmunization happens as a result of an immune response to foreign antigens encountered during blood transfusion. This gives rise to alloantibodies against red blood cells (RBCs), HLA, or human platelet antigen (HPA). HLA alloimmunization following allogeneic transfusion was shown to be a result of contaminating white blood cells (WBCs) present in the product. It is a common complication of transfusion therapy that leads to difficulties in clinical intolerance and refractoriness to platelet transfusion during patient management. Single-donor platelets, prophylactic HLA matching, leukoreduction, and irradiation of cellular blood products are some of the mechanisms to prevent HLA alloimmunization during a blood transfusion. Now, the best approach to reduce the occurrence of primary HLA alloimmunization is the removal of WBCs from the blood by filtration.

Pathogen inactivation methods to prevent transfusion-transmissible arboviruses: A systematic review and meta-analysis

OBJECTIVE

Arboviruses are emerging as a relevant threat to transfusion safety. Pathogen inactivation methods (PIMs) may reduce the risk of transmission through transfusion, as long as they meet minimum standards for effectiveness. This study aims to assess the log reduction of viral load achieved with different PIMs, according to the blood product they are used on and the arbovirus targeted.

METHODS

Systematic literature review and meta-analysis. Searches were conducted in MEDLINE and Embase. The study protocol was registered in PROSPERO CRD42022312061. We selected records reporting the log reduction of viral load achieved with the main PIMs (amotosalen + UVA light [INTERCEPT], riboflavin + UV light [Mirasol], methylene blue + visible light/UVC light [THERAFLEX], solvent detergent, amustaline [INTERCEPT] and PEN110 [Inactine]), applied to any blood product (plasma, platelets, red blood cells or whole blood) and for any arbovirus. The log reduction of viral loads was assessed by obtaining the mean log reduction factor (LRF). We compared and classified the LRF of different techniques using statistical methods.

RESULTS

We included 59 publications reporting LRF results in 17 arboviruses. For 13 arboviruses, including Chikungunya virus, Dengue virus, West Nile virus and Zika virus, at least one of the methods achieves adequate or optimal log reduction of viral load-mean LRF ≥4. The LRF achieved with riboflavin + UV light is inferior to the rest of the techniques, both overall and specifically for plasma, platelets preserved in platelet additive solution (PAS)/plasma, and red blood cells/whole blood. The LRF achieved using Mirasol is also lower for inactivating Chikungunya virus, Dengue virus and Zika virus. For West Nile virus, we found no significant differences. In plasma, the method that achieves the highest LRF is solvent/detergent; in platelets, THERAFLEX and INTERCEPT; and in red blood cells/whole blood, PEN110 (Inactine).

CONCLUSION

Not all PIMs achieve the same LRF, nor is this equivalent between the different arboviruses or blood products. Overall, the LRFs achieved using riboflavin + UV light (Mirasol) are inferior to those achieved with the rest of the PIMs. Regarding the others, LRFs vary by arbovirus and blood product. In light of the threat of different arboviruses, blood establishments should have already validated PIMs and be logistically prepared to implement these techniques quickly.

Protein Concentrations in Stored Pooled Platelet Concentrates Treated with Pathogen Inactivation by Amotosalen Plus Ultraviolet a Illumination

Platelet granules contain a diverse group of proteins. Upon activation and during storage, platelets release a number of proteins into the circulation or supernatant of stored platelet concentrate (PC). The aim of this work was to investigate the effect of pathogen inactivation (PI) on a selection of proteins released in stored platelets. Materials and Methods: PCs in platelet additive solution (PAS) were produced from whole blood donations using the buffy coat (BC) method. PCs in the treatment arm were pathogen inactivated with amotosalen and UVA, while PCs in the second arm were used as an untreated platelet control. Concentrations of 36 proteins were monitored in the PCs during storage. Results: The majority of proteins increased in concentration over the storage period. In addition, 10 of the 29 proteins that showed change had significantly different concentrations between the PI treatment and the control at one or more timepoints. A subset of six proteins displayed a PI-related drop in concentration. Conclusions: PI has limited effect on protein concentration stored PC supernatant. The protein’s changes related to PI treatment with elevated concentration implicate accelerated Platelet storage lesion (PSL); in contrast, there are potential novel benefits to PI related decrease in protein concentration that need further investigation.

A New Infectious Unit: Extracellular Vesicles Carrying Virus Populations

Viral egress and transmission have long been described to take place through single free virus particles. However, viruses can also shed into the environment and transmit as populations clustered inside extracellular vesicles (EVs), a process we had first called vesicle-mediated en bloc transmission. These membrane-cloaked virus clusters can originate from a variety of cellular organelles including autophagosomes, plasma membrane, and multivesicular bodies. Their viral cargo can be multiples of nonenveloped or enveloped virus particles or even naked infectious genomes, but egress is always nonlytic, with the cell remaining intact. Here we put forth the thesis that EV-cloaked viral clusters are a distinct form of infectious unit as compared to free single viruses (nonenveloped or enveloped) or even free virus aggregates. We discuss how efficient and prevalent these infectious EVs are in the context of virus-associated diseases and highlight the importance of their proper detection and disinfection for public health. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Riboflavin: The Health Benefits of a Forgotten Natural Vitamin

Riboflavin (RF) is a water-soluble member of the B-vitamin family. Sufficient dietary and supplemental RF intake appears to have a protective effect on various medical conditions such as sepsis, ischemia etc., while it also contributes to the reduction in the risk of some forms of cancer in humans. These biological effects of RF have been widely studied for their anti-oxidant, anti-aging, anti-inflammatory, anti-nociceptive and anti-cancer properties. Moreover, the combination of RF and other compounds or drugs can have a wide variety of effects and protective properties, and diminish the toxic effect of drugs in several treatments. Research has been done in order to review the latest findings about the link between RF and different clinical aberrations. Since further studies have been published in this field, it is appropriate to consider a re-evaluation of the importance of RF in terms of its beneficial properties.

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

BACKGROUND

The risk of bacterial contamination and the deterioration of platelet (PLT) quality limit the shelf-life of platelet concentrates (PCs). The INTERCEPT pathogen inactivation system reduces the risk of pathogen transmission by inhibiting nucleic acid replication using a combination of a photo-reactive compound and UVA illumination. The goal of this study was to investigate the effects the INTERCEPT system has on the PLT metabolome and metabolic activity.

STUDY DESIGN AND METHODS

Paired units of buffy coat-derived PCs were generated using a pool and split strategy (n = 8). The paired PCs were either treated with the INTERCEPT system or left untreated. Samples were collected on Days 1, 2, 4, and 7 of storage. Ultra-performance chromatography coupled with time-of-flight mass spectrometry was used to analyze the extra- and intracellular metabolomes. Constraint-based metabolic modeling was then used to predict the metabolic activity of the stored PLTs.

RESULTS

A relatively large number of metabolites in the extracellular environment were depleted during the processing steps of the INTERCEPT system, in particular, metabolites with hydrophobic functional groups, including acylcarnitines and lysophosphatidylcholines. In the intracellular environment, alterations in glucose and glycerophospholipid metabolism and decreased levels of 2-hydroxyglutarate were observed following the INTERCEPT treatment. Untargeted metabolomics analysis revealed residual amotosalen dimers present in the treated PCs. Systems-level analysis of PLT metabolism indicated that the INTERCEPT system does not have a significant impact on the PLT energy metabolism and nutrient utilization.

CONCLUSIONS

The INTERCEPT system significantly alters the metabolome of the stored PCs without significantly influencing PLT energy metabolism.

Pathogen inactivation with amotosalen plus UVA illumination minimally impacts microRNA expression in platelets during storage under standard blood banking conditions

BACKGROUND

To reduce the risk of transfusion transmission infection, nucleic acid targeted methods have been developed to inactivate pathogens in PCs. miRNAs have been shown to play an important role in platelet function, and changes in the abundance of specific miRNAs during storage have been observed, as have perturbation effects related to pathogen inactivation (PI) methods. The aim of this work was to investigate the effects of PI on selected miRNAs during storage.

STUDY DESIGN AND METHODS

Using a pool and split strategy, 3 identical buffy coat PC units were generated from a pool of 24 whole blood donors. Each unit received a different treatment: 1) Untreated platelet control in platelet additive solution (C-PAS); 2) Amotosalen-UVA-treated platelets in PAS (PI-PAS); and 3) untreated platelets in donor plasma (U-PL). PCs were stored for 7 days under standard blood banking conditions. Standard platelet quality control (QC) parameters and 25 selected miRNAs were analyzed.

RESULTS

During the 7-day storage period, differences were found in several QC parameters relating to PI treatment and storage in plasma, but overall the three treatments were comparable. Out of 25 miRNA tested changes in regulation of 5 miRNA in PI-PAS and 3 miRNA U-PL where detected compared to C-PAS. A statistically significant difference was observed in down regulations miR-96-5p on Days 2 and 4, 61.9% and 61.8%, respectively, in the PI-PAS treatment.

CONCLUSION

Amotosalen-UVA treatment does not significantly alter the miRNA profile of platelet concentrates generated and stored using standard blood banking conditions.

The senotherapeutic nicotinamide riboside raises platelet nicotinamide adenine dinucleotide levels but cannot prevent storage lesion

BACKGROUND

Supplementation of the nicotinamide adenine dinucleotide (NAD) precursor nicotinamide riboside (NR) has recently been shown to increase life‐span of cells, tissues, and entire organisms. [Correction added on 13 December 2019, after first online publication: In the preceding sentence, “adenine nicotinamide” was revised to “nicotinamide adenine.”] The impact of NR on platelet longevity has not been tested.

STUDY DESIGN AND METHODS

A pool‐and‐split design of buffy coat derived platelet concentrates (PCs) was used. One arm was treated with cumulative doses of NR‐triflate, the control arm with sodium triflate. Storage lesion was monitored for 23 days. Platelet metabolic and functional parameters were tested. Clearance of human platelets was measured in a mouse model of transfusion.

RESULTS

Total intracellular NAD levels in platelets decreased two‐fold from 4.8 ± 0.5 fmol (mean ± SD, n = 6) to 2.1 ± 1.8 fmol per 10³ control cells, but increased almost 10‐fold to 41.5 ± 4.1 fmol per 10³ NR treated platelets. This high intracellular NAD level had no significant impact on platelet count, mean platelet volume, swirling, nor on lactate and glucose levels. Platelet aggregation and integrin α_IIbβ₃ activation declined steadily and comparably in both conditions. GPIbα levels were slightly lower in NR‐treated platelets compared to control, but this was not caused by reduced receptor shedding because glycocalicin increased similarly. Apoptotic markers cytochrome c, Bcl‐xL, cleaved caspase‐3, and Bak were not different throughout storage for both conditions. Platelet survival in a mouse model of transfusion was not different between NR‐treated and control platelets.

CONCLUSION

Platelets carry the cellular machinery to metabolize NR into NAD at rates comparable to other eukaryotic cells. Unlike those cells, platelet life‐span cannot be prolonged using this strategy.

Methylene Blue Treatment of Grafts During Cold Ischemia Time Reduces the Risk of Hepatitis C Virus Transmission

Background

Although organ shortage is a rising problem, organs from hepatitis C virus (HCV) ribonucleic acid (RNA)-positive donors are not routinely transplanted in HCV-negative individuals. Because HCV only infects hepatocytes, other organs such as kidneys are merely contaminated with HCV via the blood. In this study, we established a protocol to reduce HCV virions during the cold ischemic time.

Methods

Standard virological assays were used to investigate the effect of antivirals, including methylene blue (MB), in different preservation solutions. Kidneys from mini pigs were contaminated with Jc1 or HCV RNA-positive human serum. Afterwards, organs were flushed with MB. Hypothermic machine perfusion was used to optimize reduction of HCV.

Results

Three different antivirals were investigated for their ability to inactivate HCV in vitro. Only MB completely inactivated HCV in the presence of all perfusion solutions. Hepatitis C virus-contaminated kidneys from mini pigs were treated with MB and hypothermic machine perfusion without any negative effect on the graft. Human liver-uPA-SCID mice did not establish HCV infection after inoculation with flow through from these kidneys.

Conclusions

This proof-of-concept study is a first step to reduce transmission of infectious HCV particles in the transplant setting and might serve as a model for other relevant pathogens.

Platelet transfusion: Current challenges

Since the late sixties, platelet concentrates are transfused to patients presenting with severe thrombocytopenia, platelet function defects, injuries, or undergoing surgery, to prevent the risk of bleeding or to treat actual hemorrhage. Current practices differ according to the country or even in different hospitals and teams. Although crucial advances have been made during the last decades, questions and debates still arise about the right doses to transfuse, the use of prophylactic or therapeutic strategies, the nature and quality of PC, the storage conditions, the monitoring of transfusion efficacy and the microbiological and immunological safety of platelet transfusion. Finally, new challenges are emerging with potential new platelet products, including cold stored or in vitro produced platelets. The most debated of these points are reviewed.

Biomolecular Consequences of Platelet Pathogen Inactivation Methods

Pathogen inactivation (PI) for platelet concentrates (PC) is a fairly recent development in transfusion medicine that is intended to decrease infectious disease transmission from the donor to the receiving patient. Effective inactivation of viruses, bacteria and eukaryotic parasites adds a layer of safety, protecting the blood supply against customary and emerging pathogens. Three PI methods have been described for platelets. These are based on photochemical damage of nucleic acids which prevents replication of most infectious pathogens and contaminating donor leukocytes. Because platelets do not replicate, the collateral damage to platelet function is considered low to non-existing. This is disputable however because photochemistry is not specific for nucleic acids and significantly affects platelet biomolecules as well. The impact of these biomolecular changes on platelet function and hemostasis is not well understood, but is increasingly being studied. The results of these studies can help explain current and future clinical observations with PI platelets, including the impact on transfusion yield and bleeding. This review summarizes the biomolecular effects of PI treatment on platelets. We conclude that despite a comparable principle of photochemical inactivation, all three methods affect platelets in different ways. This knowledge can help blood banks and transfusion specialists to guide their choice when considering the implementation or clinical use of PI treated platelets.

Riboflavin and health: A review of recent human research

There has lately been a renewed interest in Riboflavin owing to insight into its recognition as an essential component of cellular biochemistry. The knowledge of the mechanisms and regulation of intestinal absorption of riboflavin and its health implications has significantly been expanded in recent years. The purpose of this review is to provide an overview of the importance of riboflavin, its absorption and metabolism in health and diseased conditions, its deficiency and its association with various health diseases, and metabolic disorders. Efforts have been made to review the available information in literature on the relationship between riboflavin and various clinical abnormalities. The role of riboflavin has also been dealt in the prevention of a wide array of health diseases like migraine, anemia, cancer, hyperglycemia, hypertension, diabetes mellitus, and oxidative stress directly or indirectly. The riboflavin deficiency has profound effect on iron absorption, metabolism of tryptophan, mitochondrial dysfunction, gastrointestinal tract, brain dysfunction, and metabolism of other vitamins as well as is associated with skin disorders. Toxicological and photosensitizing properties of riboflavin make it suitable for biological use, such as virus inactivation, excellent photosensitizer, and promising adjuvant in chemo radiotherapy in cancer treatment. A number of recent studies have indicated and highlighted the cellular processes and biological effects associated with riboflavin supplementation in metabolic diseases. Overall, a deeper understanding of these emerging roles of riboflavin intake is essential to design better therapies for future.

Pathogen Inactivation of Cellular Blood Products-An Additional Safety Layer in Transfusion Medicine

In line with current microbial risk reduction efforts, pathogen inactivation (PI) technologies for blood components promise to reduce the residual risk of known and emerging infectious agents. The implementation of PI of labile blood components is slowly but steadily increasing. This review discusses the relevance of PI for the field of transfusion medicine and describes the available and emerging PI technologies that can be used to treat cellular blood products such as platelet and red blood cell units. In collaboration with the French medical device manufacturer Macopharma, the German Red Cross Blood Services developed a new UVC light-based PI method for platelet units, which is currently being investigated in clinical trials.

Pathogen-reduced platelets for the prevention of bleeding

BACKGROUND

Platelet transfusions are used to prevent and treat bleeding in people who are thrombocytopenic. Despite improvements in donor screening and laboratory testing, a small risk of viral, bacterial, or protozoal contamination of platelets remains. There is also an ongoing risk from newly emerging blood transfusion-transmitted infections for which laboratory tests may not be available at the time of initial outbreak.One solution to reduce the risk of blood transfusion-transmitted infections from platelet transfusion is photochemical pathogen reduction, in which pathogens are either inactivated or significantly depleted in number, thereby reducing the chance of transmission. This process might offer additional benefits, including platelet shelf-life extension, and negate the requirement for gamma-irradiation of platelets. Although current pathogen-reduction technologies have been proven to reduce pathogen load in platelet concentrates, a number of published clinical studies have raised concerns about the effectiveness of pathogen-reduced platelets for post-transfusion platelet count recovery and the prevention of bleeding when compared with standard platelets.This is an update of a Cochrane review first published in 2013.

OBJECTIVES

To assess the effectiveness of pathogen-reduced platelets for the prevention of bleeding in people of any age requiring platelet transfusions.

SEARCH METHODS

We searched for randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 9), MEDLINE (from 1946), Embase (from 1974), CINAHL (from 1937), the Transfusion Evidence Library (from 1950), and ongoing trial databases to 24 October 2016.

SELECTION CRITERIA

We included RCTs comparing the transfusion of pathogen-reduced platelets with standard platelets, or comparing different types of pathogen-reduced platelets.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified five new trials in this update of the review. A total of 15 trials were eligible for inclusion in this review, 12 completed trials (2075 participants) and three ongoing trials. Ten of the 12 completed trials were included in the original review. We did not identify any RCTs comparing the transfusion of one type of pathogen-reduced platelets with another.Nine trials compared Intercept® pathogen-reduced platelets to standard platelets, two trials compared Mirasol® pathogen-reduced platelets to standard platelets; and one trial compared both pathogen-reduced platelets types to standard platelets. Three RCTs were randomised cross-over trials, and nine were parallel-group trials. Of the 2075 participants enrolled in the trials, 1981 participants received at least one platelet transfusion (1662 participants in Intercept® platelet trials and 319 in Mirasol® platelet trials).One trial included children requiring cardiac surgery (16 participants) or adults requiring a liver transplant (28 participants). All of the other participants were thrombocytopenic individuals who had a haematological or oncological diagnosis. Eight trials included only adults.Four of the included studies were at low risk of bias in every domain, while the remaining eight included studies had some threats to validity.Overall, the quality of the evidence was low to high across different outcomes according to GRADE methodology.We are very uncertain as to whether pathogen-reduced platelets increase the risk of any bleeding (World Health Organization (WHO) Grade 1 to 4) (5 trials, 1085 participants; fixed-effect risk ratio (RR) 1.09, 95% confidence interval (CI) 1.02 to 1.15; I2 = 59%, random-effect RR 1.14, 95% CI 0.93 to 1.38; I2 = 59%; low-quality evidence).There was no evidence of a difference between pathogen-reduced platelets and standard platelets in the incidence of clinically significant bleeding complications (WHO Grade 2 or higher) (5 trials, 1392 participants; RR 1.10, 95% CI 0.97 to 1.25; I2 = 0%; moderate-quality evidence), and there is probably no difference in the risk of developing severe bleeding (WHO Grade 3 or higher) (6 trials, 1495 participants; RR 1.24, 95% CI 0.76 to 2.02; I2 = 32%; moderate-quality evidence).There is probably no difference between pathogen-reduced platelets and standard platelets in the incidence of all-cause mortality at 4 to 12 weeks (6 trials, 1509 participants; RR 0.81, 95% CI 0.50 to 1.29; I2 = 26%; moderate-quality evidence).There is probably no difference between pathogen-reduced platelets and standard platelets in the incidence of serious adverse events (7 trials, 1340 participants; RR 1.09, 95% CI 0.88 to 1.35; I2 = 0%; moderate-quality evidence). However, no bacterial transfusion-transmitted infections occurred in the six trials that reported this outcome.Participants who received pathogen-reduced platelet transfusions had an increased risk of developing platelet refractoriness (7 trials, 1525 participants; RR 2.94, 95% CI 2.08 to 4.16; I2 = 0%; high-quality evidence), though the definition of platelet refractoriness differed between trials.Participants who received pathogen-reduced platelet transfusions required more platelet transfusions (6 trials, 1509 participants; mean difference (MD) 1.23, 95% CI 0.86 to 1.61; I2 = 27%; high-quality evidence), and there was probably a shorter time interval between transfusions (6 trials, 1489 participants; MD -0.42, 95% CI -0.53 to -0.32; I2 = 29%; moderate-quality evidence). Participants who received pathogen-reduced platelet transfusions had a lower 24-hour corrected-count increment (7 trials, 1681 participants; MD -3.02, 95% CI -3.57 to -2.48; I2 = 15%; high-quality evidence).None of the studies reported quality of life.We did not evaluate any economic outcomes.There was evidence of subgroup differences in multiple transfusion trials between the two pathogen-reduced platelet technologies assessed in this review (Intercept® and Mirasol®) for all-cause mortality and the interval between platelet transfusions (favouring Intercept®).

AUTHORS' CONCLUSIONS

Findings from this review were based on 12 trials, and of the 1981 participants who received a platelet transfusion only 44 did not have a haematological or oncological diagnosis.In people with haematological or oncological disorders who are thrombocytopenic due to their disease or its treatment, we found high-quality evidence that pathogen-reduced platelet transfusions increase the risk of platelet refractoriness and the platelet transfusion requirement. We found moderate-quality evidence that pathogen-reduced platelet transfusions do not affect all-cause mortality, the risk of clinically significant or severe bleeding, or the risk of a serious adverse event. There was insufficient evidence for people with other diagnoses.All three ongoing trials are in adults (planned recruitment 1375 participants) with a haematological or oncological diagnosis.

Cellulose-based virus-retentive filters: a review

Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption-elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.

Xenotropic Murine Leukemia Virus-Related Virus (XMRV) and the Safety of the Blood Supply

In 2006, a new virus, xenotropic murine leukemia virus-related virus (XMRV), was discovered in a cohort of U.S. men with prostate cancer. Soon after this initial finding, XMRV was also detected in samples from patients with chronic fatigue syndrome (CFS). The blood community, which is highly sensitive to the threat of emerging infectious diseases since the HIV/AIDS crisis, recommended indefinite deferral of all blood donors with a history of CFS. As XMRV research progressed, conflicting results emerged regarding the importance of this virus in the pathophysiology of prostate cancer and/or CFS. Molecular biologists traced the development of XMRV to a recombination event in a laboratory mouse that likely occurred circa 1993. The virus was propagated via cell lines derived from a tumor present in this mouse and spread through contamination of laboratory samples. Well-controlled experiments showed that detection of XMRV was due to contaminated samples and was not a marker of or a causal factor in prostate cancer or CFS. This paper traces the development of XMRV in the prostate and CFS scientific communities and explores the effect it had on the blood community.

MPLEx: a method for simultaneous pathogen inactivation and extraction of samples for multi-omics profiling

The continued emergence and spread of infectious agents is of great concern, and systems biology approaches to infectious disease research can advance our understanding of host-pathogen relationships and facilitate the development of new therapies and vaccines. Molecular characterization of infectious samples outside of appropriate biosafety containment can take place only subsequent to pathogen inactivation. Herein, we describe a modified Folch extraction using chloroform/methanol that facilitates the molecular characterization of infectious samples by enabling simultaneous pathogen inactivation and extraction of proteins, metabolites, and lipids for subsequent mass spectrometry-based multi-omics measurements. This single-sample metabolite, protein and lipid extraction (MPLEx) method resulted in complete inactivation of clinically important bacterial and viral pathogens with exposed lipid membranes, including Yersinia pestis, Salmonella Typhimurium, and Campylobacter jejuni in pure culture, and Yersinia pestis, Campylobacter jejuni, and West Nile, MERS-CoV, Ebola, and influenza H7N9 viruses in infection studies. In addition, >99% inactivation, which increased with solvent exposure time, was also observed for pathogens without exposed lipid membranes including community-associated methicillin-resistant Staphylococcus aureus, Clostridium difficile spores and vegetative cells, and adenovirus type 5. The overall pipeline of inactivation and subsequent proteomic, metabolomic, and lipidomic analyses was evaluated using a human epithelial lung cell line infected with wild-type and mutant influenza H7N9 viruses, thereby demonstrating that MPLEx yields biomaterial of sufficient quality for subsequent multi-omics analyses. Based on these experimental results, we believe that MPLEx will facilitate systems biology studies of infectious samples by enabling simultaneous pathogen inactivation and multi-omics measurements from a single specimen with high success for pathogens with exposed lipid membranes.

Development of High Hydrostatic Pressure Applied in Pathogen Inactivation for Plasma

High hydrostatic pressure has been used to inactivate pathogens in foods for decades. There is a great potential to adapt this technology to inactivate pathogens in plasma and derivatives. To better evaluate the potential of this method, pathogen inoculated plasma samples were pressurized under different pressure application modes and temperatures. The inactivation efficacy of pathogens and activities of plasma proteins were monitored after treatment. The CFUs of E.coli was examined as the indicator of the inactivation efficiency. The factor V and VIII were chosen as the indicator of the plasma function. Preliminary experiments identified optimized treatment conditions: 200-250MPa, with 5×1 minute multi-pulsed high pressure at near 0°C (ice-water bath). Under this conditions, the inactivation efficacy of EMCV was >8.5log. The CFUs of E. coli were reduced by 7.5log, B. cereus were 8log. However, PPV and S. aureus cannot be inactivated efficiently. The activities of factor II, VII, IX, X, XI, XII, fibrinogen, IgG, IgM stayed over 95% compared to untreated. Factor V and VIII activity was maintained at 46–63% and 77–82%, respectively.

Past, present and forecast of transfusion medicine: What has changed and what is expected to change?

Blood transfusion is the second most used medical procedures in health care systems worldwide. Over the last few decades, significant changes have been evolved in transfusion medicine practices. These changes were mainly needed to increase safety, efficacy, and availability of blood products as well as reduce recipients' unnecessary exposure to allogeneic blood. Blood products collection, processing, and storage as well as transfusion practices throughout all patient populations were the main stream of these changes. Health care systems across the world have adopted some or most of these changes to reduce transfusion risks, to improve overall patients' outcome, and to reduce health care costs. In this article, we are going to present and discuss some of these recent modifications and their impact on patients' safety.

Health Technology Assessment of pathogen reduction technologies applied to plasma for clinical use

Although existing clinical evidence shows that the transfusion of blood components is becoming increasingly safe, the risk of transmission of known and unknown pathogens, new pathogens or re-emerging pathogens still persists. Pathogen reduction technologies may offer a new approach to increase blood safety. The study is the output of collaboration between the Italian National Blood Centre and the Post-Graduate School of Health Economics and Management, Catholic University of the Sacred Heart, Rome, Italy. A large, multidisciplinary team was created and divided into six groups, each of which addressed one or more HTA domains.Plasma treated with amotosalen + UV light, riboflavin + UV light, methylene blue or a solvent/detergent process was compared to fresh-frozen plasma with regards to current use, technical features, effectiveness, safety, economic and organisational impact, and ethical, social and legal implications. The available evidence is not sufficient to state which of the techniques compared is superior in terms of efficacy, safety and cost-effectiveness. Evidence on efficacy is only available for the solvent/detergent method, which proved to be non-inferior to untreated fresh-frozen plasma in the treatment of a wide range of congenital and acquired bleeding disorders. With regards to safety, the solvent/detergent technique apparently has the most favourable risk-benefit profile. Further research is needed to provide a comprehensive overview of the cost-effectiveness profile of the different pathogen-reduction techniques. The wide heterogeneity of results and the lack of comparative evidence are reasons why more comparative studies need to be performed.

Solvent/detergent plasma: pharmaceutical characteristics and clinical experience

The solvent/detergent treatment is an established virus inactivation technology that has been industrially applied for manufacturing plasma derived medicinal products for almost 30 years. Solvent/detergent plasma is a pharmaceutical product with standardised content of clotting factors, devoid of antibodies implicated in transfusion-related acute lung injury pathogenesis, and with a very high level of decontamination from transfusion-transmissible infectious agents. Many clinical studies have confirmed its safety and efficacy in the setting of congenital as well as acquired bleeding disorders. This narrative review will focus on the pharmaceutical characteristics of solvent/detergent plasma and the clinical experience with this blood product.

Fresh frozen plasma for cardiovascular surgery

BACKGROUND

Fresh frozen plasma (FFP) is a blood component containing procoagulant factors, which is sometimes used in cardiovascular surgery with the aim of reducing the risk of bleeding. The purpose of this review is to assess the risk of mortality for patients undergoing cardiovascular surgery who receive FFP.

OBJECTIVES

To evaluate the risk to benefit ratio of FFP transfusion in cardiovascular surgery for the treatment of bleeding patients or for prophylaxis against bleeding.

SEARCH METHODS

We searched 11 bibliographic databases and four ongoing trials databases including the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 3, 2015), MEDLINE (OvidSP, 1946 to 21 April 2015), EMBASE (OvidSP, 1974 to 21 April 2015), PubMed (e-publications only: searched 21 April 2015), ClinicalTrials.gov, World Health Organization (WHO) ICTRP and the ISRCTN Register (searched 21 April 2015). We also searched the references of all identified trials and relevant review articles. We did not limit the searches by language or publication status.

SELECTION CRITERIA

We included randomised controlled trials in patients undergoing major cardiac or vascular surgery who were allocated to a FFP group or a comparator (no plasma or an active comparator, either clinical plasma (any type) or a plasma-derived blood product). We included participants of any age (neonates, children and adults). We excluded studies of plasmapheresis and plasma exchange.

DATA COLLECTION AND ANALYSIS

Two authors screened all electronically derived citations and abstracts of papers identified by the review search strategy. Two authors assessed risk of bias in the included studies and extracted data independently. We took care to note whether FFP was used therapeutically or prophylactically within each trial.

MAIN RESULTS

We included 15 trials, with a total of 755 participants for analysis in the review. Fourteen trials compared prophylactic use of FFP against no FFP. One study compared therapeutic use of two types of plasma. The timing of intervention varied, including FFP transfusion at the time of heparin neutralisation and stopping cardiopulmonary bypass (CPB) (seven trials), with CPB priming (four trials), after anaesthesia induction (one trial) and postoperatively (two trials). Twelve trials excluded patients having emergency surgery and nine excluded patients with coagulopathies.Overall the trials were small, with only four reporting an a priori sample size calculation. No trial was powered to determine changes in mortality as a primary outcome. There was either high risk of bias, or unclear risk, in the majority of trials included in this review.There was no difference in the number of deaths between the intervention arms in the six trials (with 287 patients) reporting mortality (very low quality evidence). There was also no difference in blood loss in the first 24 hours for neonatal/paediatric patients (four trials with 138 patients; low quality evidence): mean difference (MD) -1.46 ml/kg (95% confidence interval (CI) -4.7 to 1.78 ml/kg); or adult patients (one trial with 120 patients): MD -12.00 ml (95% CI -101.16 to 77.16 ml).Transfusion with FFP was inferior to control for preventing patients receiving any red cell transfusion: Peto odds ratio (OR) 2.57 (95% CI 1.30 to 5.08; moderate quality evidence). There was a difference in prothrombin time within two hours of FFP transfusion in eight trials (with 210 patients; moderate quality evidence) favouring the FFP arm: MD -0.71 seconds (95% CI -1.28 to -0.13 seconds). There was no difference in the risk of returning to theatre for reoperation (eight trials with 398 patients; moderate quality evidence): Peto OR 0.81 (95% CI 0.26 to 2.57). Only one included study reported adverse events as an outcome and reported no significant adverse events following FFP transfusion.

AUTHORS' CONCLUSIONS

This review has found no evidence to support the prophylactic administration of FFP to patients without coagulopathy undergoing elective cardiac surgery. There was insufficient evidence about treatment of patients with coagulopathies or those who are undergoing emergency surgery. There were no reported adverse events attributable to FFP transfusion, although there was a significant increase in the number of patients requiring red cell transfusion who were randomised to FFP. Variability in outcome reporting between trials precluded meta-analysis for many outcomes across all trials, and there was evidence of a high risk of bias in most of the studies. Further adequately powered studies of FFP, or comparable pro-haemostatic agents, are required to assess whether larger reductions in prothrombin time translate into clinical benefits. Overall the evidence from randomised controlled trials for the safety and efficacy of prophylactic transfusion of FFP for cardiac surgery is insufficient.

Photosensitizing nanoparticles and the modulation of ROS generation

The association of PhotoSensitizer (PS) molecules with nanoparticles (NPs) forming photosensitizing NPs, has emerged as a therapeutic strategy to improve PS tumor targeting, to protect PS from deactivation reactions and to enhance both PS solubility and circulation time. Since association with NPs usually alters PS photophysical and photochemical properties, photosensitizing NPs are an important tool to modulate ROS generation. Depending on the design of the photosensitizing NP, i.e., type of PS, the NP material and the method applied for the construction of the photosensitizing NP, the deactivation routes of the excited state can be controlled, allowing the generation of either singlet oxygen or other reactive oxygen species (ROS). Controlling the type of generated ROS is desirable not only in biomedical applications, as in Photodynamic Therapy where the type of ROS affects therapeutic efficiency, but also in other technological relevant fields like energy conversion, where the electron and energy transfer processes are necessary to increase the efficiency of photoconversion cells. The current review highlights some of the recent developments in the design of Photosensitizing NPs aimed at modulating the primary photochemical events after light absorption.

The low photo-inactivation rate of bacteria in human plasma II. Inhibition of methylene blue bleaching in plasma and effective bacterial destruction by the addition of dilute acetic acid to human plasma

Bacteria in human plasma resist methylene blue photo-inactivation. The addition of dilute acetic acid prevents MB bleaching and restores the efficient destruction of bacteria.

The Effects of Ultraviolet Light and Riboflavin on Inactivation of Viruses and the Quality of Platelet Concentrates at Laboratory Scale

BACKGROUND

This study investigated the effects of Riboflavin (RB) combined with different doses of UV on Platelet Concentrate (PC) which was infected by three models of virus. Platelet quality after treatment was also assessed.

METHODS

Three models of virus used in this study were Vesicular Stomatitis Virus (VSV), Herpes Simplex Virus (HSV), and Polio virus, which were added to PC. After photochemical treatment with RB and UV light, residual viral infectivity was titrated using 50% Tissue Culture Infective Dose (TCID50)/ml. This treatment was done with concentration of 50 μM of RB and different doses of UV light (0.24, 0.48, 0.97, 1.29 J/cm (2)). Platelet quality was assessed by measuring pH, Lactate Dehydrogenase (LDH), MTT assay and cell count after treatments and during 4 days of storage against control groups.

RESULTS

Concentration of 50 μM RB with combination of 1.29 J/cm (2) dose of UV resulted in the highest titer reduction of VSV (4 log 10) and HSV (4.26 log10) and lowest titer reduction of Polio virus (2.6 log10). No significant difference was observed between different doses in comparison with control groups. In all treatment groups, the storage stability of platelets in PC was in the acceptable range in comparison with control group.

CONCLUSION

This study indicated that RB/UV treatment was a promising pathogen reduction technique in PC and had limited effects on platelet quality. However, further optimization of this method is necessary to deal with blood-borne viruses like non-enveloped viruses.

Chemical and biological mechanisms of pathogen reduction technologies

Within the last decade new technologies have been developed and implemented which employ light, often in the presence of a photosensitizer, to inactivate pathogens that reside in human blood products for the purpose of transfusion. These pathogen reduction technologies attempt to find the proper balance between pathogen kill and cell quality. Each system utilizes various chemistries that not only impact which pathogens they can inactivate and how, but also how the treatments affect the plasma and cellular proteins and to what degree. This paper aims to present the various chemical mechanisms for pathogen reduction in transfusion medicine that are currently practiced or in development.

Inactivation of model viruses suspended in fresh frozen plasma using novel methylene blue based device

BACKGROUND AND OBJECTIVE

There is a concern on safety of human Fresh Frozen Plasma (FFP) as it is a source of some medicinal products. The possibility of transmission of blood-borne are reported often due to emerging viruses. There are some Pathogen Reduction Technologies (PRT) to inactivate viruses. Methylene Blue (MB) based method is one of them. The aim of this study was to examine new designated device to inactivate model viruses.

MATERIALS AND METHODS

Four model viruses were used in this study:Vesicular stomatitis virus (VSV), Herpes Simplex Virus I (HSV-1), Bovine Viral DiarrheaVirus(BVDV) and Polio Virus.50% Tissue Culture Infective Dose (TCID 50) and Reed-Muench Methods were used to titer the viruses. MB in two final concentration of 0.1 μM and 1 μM and illumination in about 627nm with red LED (Lamp Emitting Diode) for 15, 30, 45 and 60 minutes were used. Three replicates employed for each experiments.

RESULTS

1μMconcentration of MB showed more effective than 0.1μMin all designed illumination period for inactivation of HSV, VSV and BVDV. This method also demonstrated best results for enveloped model viruses. The most Log reduction for HSV, VSV and BVDV were6.28, 5.54 and 6.22, respectively. For HSV and BVDV inactivation, the best illumination period was 45 minutes.

CONCLUSION

Model viruses showed sensitivity combination of MB and illumination using red LEDs. As results show this device could inactivate model viruses and reduce their titer very close to approved commercial devices, in compare.

Rationale and mechanism for the low photoinactivation rate of bacteria in plasma

The rate of bacterial photoinactivation in plasma by methylene blue (MB), especially for Gram-negative bacteria, has been reported to be lower, by about an order of magnitude, than the rate of inactivation in PBS and water solutions. This low inactivation rate we attribute to the bleaching of the 660-nm absorption band of MB in plasma that results in low yields of MB triplet states and consequently low singlet oxygen generation. We have recorded the change of the MB 660-nm-band optical density in plasma, albumin, and cysteine solutions, as a function of time, after 661-nm excitation. The transient triplet spectra were recorded and the singlet oxygen generated in these solutions was determined by the rate of decrease in the intensity of the 399-nm absorption band of 9, 10-anthracene dipropionic acid. We attribute the bleaching of MB, low singlet oxygen yield, and consequently the low inactivation rate of bacteria in plasma to the attachment of a hydrogen atom, from the S-H group of cysteine, to the central nitrogen atom of MB and formation of cysteine dimer.

Oxygen removal during pathogen inactivation with riboflavin and UV light preserves protein function in plasma for transfusion

BACKGROUND AND OBJECTIVE

Photochemical pathogen inactivation technologies (PCT) for individual transfusion products act by inhibition of replication through irreversibly damaging nucleic acids. Concern on the collateral impact of PCT on the blood component's integrity has caused reluctance to introduce this technology in routine practice. This work aims to uncover the mechanism of damage to plasma constituents by riboflavin pathogen reduction technology (RF-PRT).

METHODS

Activity and antigen of plasma components were determined following RF-PRT in the presence or absence of dissolved molecular oxygen.

RESULTS

Employing ADAMTS13 as a sentinel molecule in plasma, our data show that its activity and antigen are reduced by 23 ± 8% and 29 ± 9% (n = 24), respectively, which corroborates with a mean decrease of 25% observed for other coagulation factors. Western blotting of ADAMTS13 shows decreased molecular integrity, with no obvious indication of additional proteolysis nor is riboflavin able to directly inhibit the enzyme. However, physical removal of dissolved oxygen prior to RF-PRT protects ADAMTS13 as well as FVIII and fibrinogen from damage, indicating a direct role for reactive oxygen species. Redox dye measurements indicate that superoxide anions are specifically generated during RF-PRT. Protein carbonyl content as a marker of disseminated irreversible biomolecular damage was significantly increased (3·1 ± 0·8 vs. 1·6 ± 0·5 nmol/mg protein) following RF-PRT, but not in the absence of dissolved molecular oxygen (1·8 ± 0·4 nmol/mg).

CONCLUSIONS

RF-PRT of single plasma units generates reactive oxygen species that adversely affect biomolecular integrity of relevant plasma constituents, a side-effect, which can be bypassed by applying hypoxic conditions during the pathogen inactivation process.

Viral inactivation in hemotherapy: systematic review on inactivators with action on nucleic acids

The aim of this study was to conduct a systematic review on the photoinactivators used in hemotherapy, with action on viral genomes. The SciELO, Science Direct, PubMed and Lilacs databases were searched for articles. The inclusion criterion was that these should be articles on inactivators with action on genetic material that had been published between 2000 and 2010. The key words used in identifying such articles were "hemovigilance", "viral inactivation", "photodynamics", "chemoprevention" and "transfusion safety". Twenty-four articles on viral photoinactivation were found with the main photoinactivators covered being: methylene blue, amotosalen HCl, S-303 frangible anchor linker effector (FRALE), riboflavin and inactin. The results showed that methylene blue has currently been studied least, because it diminishes coagulation factors and fibrinogen. Riboflavin has been studied most because it is a photoinactivator of endogenous origin and has few collateral effects. Amotosalen HCl is effective for platelets and is also used on plasma, but may cause changes both to plasma and to platelets, although these are not significant for hemostasis. S-303 FRALE may lead to neoantigens in erythrocytes and is less indicated for red-cell treatment; in such cases, PEN 110 is recommended. Thus, none of the methods for pathogen reduction is effective for all classes of agents and for all blood components, but despite the high cost, these photoinactivators may diminish the risk of blood-transmitted diseases.

Plasma constituent integrity in pre-storage vs. post-storage riboflavin and UV-light treatment--a comparative study

Treatment of fresh frozen plasma (FFP) by riboflavin (RB) and ultraviolet (UV) light inhibits nucleic acid replication, leading to inactivation of white blood cells (WBCs) and pathogens. The goal of this study was to compare the effects of pathogen reduction technology (PRT) treatment on the plasma protein content based on biochemical, immune and hemostatic characteristics in "typical" pre-storage vs. post-storage PRT-treatment setting. Following whole blood centrifugation, separated plasma units were: (a) inactivated and frozen (pre-storage setting or control group [CG]) or (b) immediately frozen (post-storage setting or study group [SG]) afterward thawed, inactivated and stored at -40 ± 5°C (cryostorage). Plasma units were inactivated by the Mirasol PRT system (TerumoBCT, USA). Using multi-laboratory techniques and equipments, biochemistry (Advia 1800; Siemens, Germany), IgM, IgG and IgA, complement components C3 and C4 (BNA II nefelometer analyzer; Siemens, Germany), as well as CH50 activity (Behring coagulation timer; Siemens, Germany) were investigated. Procoagulant and inhibitor factors, such as antithrombin-III (AT-III), and protein C (PC) were determined by BCS XP Coagulation system (Siemens, Germany). There were neither significant changes in final protein levels, nor any differences in plasma immunoglobulin levels investigated. In the final samples CH50 activity was reduced in both investigated groups. The plasma concentration of the complement C3 following post-storage treatment was significantly (p<0.05) higher than in pre-storage setting. There was a trend of depletion of procoagulant activities in both, pre-storage and post-storage PRT-treatment (initial vs. final values), but there were no significant differences between two groups. Results confirmed that AT-III was significantly higher after post-storage inactivation. In conclusion, this study confirmed that there were not clinically relevant intergroup (pre-storage vs. post-storage PRT-treatment) differences in plasma constituent levels. Post-storage treated FFP remains, protein quantity, and activity well, and therefore can be used in clinical practice. Previously cryostored or quarantine FFP units (despite the reduced quarantine period after NAT/PCR testing) could be safely and effectively inactivated, directly prior to clinical application.

Update on the use of pathogen-reduced human plasma and platelet concentrates

The use of pathogen reduction technologies (PRTs) for labile blood components is slowly but steadily increasing. While pathogen-reduced plasma is already used routinely, efficacy and safety concerns impede the widespread use of pathogen-reduced platelets. The supportive and often prophylactic nature of blood component therapy in a variety of clinical situations complicates the clinical evaluation of these novel blood products. However, an increasing body of evidence on the clinical efficacy, safety, cost-benefit ratio and development of novel technologies suggests that pathogen reduction has entered a stage of maturity that could further increase the safety margin in haemotherapy. This review summarizes the clinical evidence on PRTs for plasma and platelet products that are currently licensed or under development.

Pathogen-reduced platelets for the prevention of bleeding

BACKGROUND

Platelet transfusions are used to prevent and treat bleeding in patients who are thrombocytopenic. Despite improvements in donor screening and laboratory testing, a small risk of viral, bacterial or protozoal contamination of platelets remains. There is also an ongoing risk from newly emerging blood transfusion-transmitted infections (TTIs) for which laboratory tests may not be available at the time of initial outbreak.One solution to reduce further the risk of TTIs from platelet transfusion is photochemical pathogen reduction, a process by which pathogens are either inactivated or significantly depleted in number, thereby reducing the chance of transmission. This process might offer additional benefits, including platelet shelf-life extension, and negate the requirement for gamma-irradiation of platelets. Although current pathogen-reduction technologies have been proven significantly to reduce pathogen load in platelet concentrates, a number of published clinical studies have raised concerns about the effectiveness of pathogen-reduced platelets for post-transfusion platelet recovery and the prevention of bleeding when compared with standard platelets.

OBJECTIVES

To assess the effectiveness of pathogen-reduced platelets for the prevention of bleeding in patients requiring platelet transfusions.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2013, Issue 1), MEDLINE (1950 to 18 February 2013), EMBASE (1980 to 18 February 2013), CINAHL (1982 to 18 February 2013) and the Transfusion Evidence Library (1980 to 18 February 2013). We also searched several international and ongoing trial databases and citation-tracked relevant reference lists. We requested information on possible unpublished trials from known investigators in the field.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing the transfusion of pathogen-reduced platelets with standard platelets. We did not identify any RCTs which compared the transfusion of one type of pathogen-reduced platelets with another.

DATA COLLECTION AND ANALYSIS

One author screened all references, excluding duplicates and those clearly irrelevant. Two authors then screened the remaining references, confirmed eligibility, extracted data and analysed trial quality independently. We requested and obtained a significant amount of missing data from trial authors. We performed meta-analyses where appropriate using the fixed-effect model for risk ratios (RR) or mean differences (MD), with 95% confidence intervals (95% CI), and used the I² statistic to explore heterogeneity, employing the random-effects model when I² was greater than 30%.

MAIN RESULTS

We included 10 trials comparing pathogen-reduced platelets with standard platelets. Nine trials assessed Intercept® pathogen-reduced platelets and one trial Mirasol® pathogen-reduced platelets. Two were randomised cross-over trials and the remaining eight were parallel-group RCTs. In total, 1422 participants were available for analysis across the 10 trials, of which 675 participants received Intercept® and 56 Mirasol® platelet transfusions. Four trials assessed the response to a single study platelet transfusion (all Intercept®) and six to multiple study transfusions (Intercept® (N = 5), Mirasol® (N = 1)) compared with standard platelets.We found the trials to be generally at low risk of bias but heterogeneous regarding the nature of the interventions (platelet preparation), protocols for platelet transfusion, definitions of outcomes, methods of outcome assessment and duration of follow-up.Our primary outcomes were mortality, 'any bleeding', 'clinically significant bleeding' and 'severe bleeding', and were grouped by duration of follow-up: short (up to 48 hours), medium (48 hours to seven days) or long (more than seven days). Meta-analysis of data from five trials of multiple platelet transfusions reporting 'any bleeding' over a long follow-up period found an increase in bleeding in those receiving pathogen-reduced platelets compared with standard platelets using the fixed-effect model (RR 1.09, 95% CI 1.02 to 1.15, I² = 59%); however, this meta-analysis showed no difference between treatment arms when using the random-effects model (RR 1.14, 95% CI 0.93 to 1.38).There was no evidence of a difference between treatment arms in the number of patients with 'clinically significant bleeding' (reported by four out of the same five trials) or 'severe bleeding' (reported by all five trials) (respectively, RR 1.06, 95% CI 0.93 to 1.21, I² = 2%; RR 1.27, 95% CI 0.76 to 2.12, I² = 51%). We also found no evidence of a difference between treatment arms for all-cause mortality, acute transfusion reactions, adverse events, serious adverse events and red cell transfusion requirements in the trials which reported on these outcomes. No bacterial transfusion-transmitted infections occurred in the six trials that reported this outcome.Although the definition of platelet refractoriness differed between trials, the relative risk of this event was 2.74 higher following pathogen-reduced platelet transfusion (RR 2.74, 95% CI 1.84 to 4.07, I² = 0%). Participants required 7% more platelet transfusions following pathogen-reduced platelet transfusion when compared with standard platelet transfusion (MD 0.07, 95% CI 0.03 to 0.11, I² = 21%), although the interval between platelet transfusions was only shown to be significantly shorter following multiple Intercept® pathogen-reduced platelet transfusion when compared with standard platelet transfusion (MD -0.51, 95% CI -0.66 to -0.37, I² = 0%). In trials of multiple pathogen-reduced platelets, our analyses showed the one- and 24-hour count and corrected count increments to be significantly inferior to standard platelets. However, one-hour increments were similar in trials of single platelet transfusions, although the 24-hour count and corrected count increments were again significantly lower.

AUTHORS' CONCLUSIONS

We found no evidence of a difference in mortality, 'clinically significant' or 'severe bleeding', transfusion reactions or adverse events between pathogen-reduced and standard platelets. For a range of laboratory outcomes the results indicated evidence of some benefits for standard platelets over pathogen-reduced platelets. These conclusions are based on data from 1422 patients included in 10 trials. Results from ongoing or new trials are required to determine if there are clinically important differences in bleeding risk between pathogen-reduced platelet transfusions and standard platelet transfusions. Given the variability in trial design, bleeding assessment and quality of outcome reporting, it is recommended that future trials apply standardised approaches to outcome assessment and follow-up, including safety reporting.

Proteomics applied to transfusion plasma: the beginning of the story

'Safe blood' is and has always been the major concern in transfusion medicine. Plasma can undergo virus inactivation treatments based on physicochemical, photochemical or thermal methodologies for pathogen inactivation. The validation of these treatments is essentially based on clottability assays and clotting factors' titration; however, their impact on plasma proteins at the molecular level has not yet been evaluated. Proteomics appears as particularly adapted to identify, to localize and, consequently, to correlate these modifications to the biological activity change. At the crossroads of biology and analytical sciences, proteomics is the large-scale study of proteins in tissues, physiological fluids or cells at a given moment and in a precise environment. The proteomic strategy is based on a set of methodologies involving separative techniques like mono- and bidimensional gel electrophoresis and chromatography, analytical techniques, especially mass spectrometry, and bioinformatics. Even if plasma has been extensively studied since the very beginning of proteomics, its application to transfusion medicine has just begun. In the first part of this review, we present the principles of proteomics analysis. Then, we propose a state of the art of proteomics applied to plasma analysis. Finally, the use of proteomics for the evaluation of the impact of storage conditions and pathogen inactivation treatments applied to transfusion plasma and for the evaluation of therapeutic protein fractionated is discussed.

Monitoring drug residues in donor blood/plasma samples using LC-(MS)/MS--a pilot study

Quality assurance of pharmaceutical products is of particular importance and thoroughly controlled. Among these, the preparation of human plasma follows strict guidelines from the point of donor selection to product processing. While various precautions particularly concerning antiviral treatment as well as quality assessment are standard procedure, tests for drug residues are rarely, if at all, conducted with fresh frozen plasma products. With the constantly increasing sensitivity and specificity of modern analytical instruments, the detection of trace amounts of therapeutics in plasma is feasible and can be applied to blood products where considered appropriate. To estimate the prevalence of a selection of commonly prescribed and over-the-counter drugs (including diuretics, beta-receptor blocking agents, contraceptives, β2 -agonists, antibiotics, antidepressants, analgesics, opioids, glucocorticosteroids, benzodiazepines, stimulants, and oral anti-diabetics) as well as cannabinoids in human donor plasma, a total of 100 specimens (61 female, 39 male) collected at the German Red Cross Organization in 2012 was subjected to an established analytical approach. The methodology was based on protein precipitation followed by liquid chromatographic-high resolution/high accuracy mass spectrometric analysis. Following initial test results, confirmatory analyses were conducted with respective reference substances employing a conventional liquid chromatography-triple-quadrupole mass spectrometer (LC-MS/MS) apparatus. Out of one hundred samples, five were found to contain diuretics (four hydrochlorothiazide and one torasemide), five contained beta-receptor blocking agents (four bisoprolol and one metoprolol), one was found with residues of pseudoephedrine (stimulant) and one with drosperinone (contraceptive). Overall, 12% of samples yielded detectable amounts of drug residues at concentrations estimated to levels common to individuals under therapeutic treatment. In addition, six aliquots of different lots of commercially available plasma preparations with solvent-detergent processing were tested. Here, no drug residues of the targeted therapeutics were detected.

Prospects for a novel ultrashort pulsed laser technology for pathogen inactivation

The threat of emerging pathogens and microbial drug resistance has spurred tremendous efforts to develop new and more effective antimicrobial strategies. Recently, a novel ultrashort pulsed (USP) laser technology has been developed that enables efficient and chemical-free inactivation of a wide spectrum of viral and bacterial pathogens. Such a technology circumvents the need to introduce potentially toxic chemicals and could permit safe and environmentally friendly pathogen reduction, with a multitude of possible applications including the sterilization of pharmaceuticals and blood products, and the generation of attenuated or inactivated vaccines.

Preparation of cryoprecipitate from riboflavin and UV light-treated plasma

BACKGROUND AND OBJECTIVES

The Mirasol® pathogen reduction technology system for plasma is based on a riboflavin and UV light treatment process resulting in pathogen inactivation due to irreversible, photochemically induced damage of nucleic acids. This study was undertaken to evaluate the possibility of making pathogen reduced cryoprecipitate from riboflavin and UV light- treated plasma that meets the quality requirements specified by UK and European guidelines for untreated cryoprecipitate.

MATERIALS AND METHODS

Cryoprecipitate was made from riboflavin and UV light-treated plasma. Plasma units were thawed over a 20 h period at 4°C, and variable centrifugation settings (from 654 g for 2 min to 5316 g for 6 min) were applied to identify the optimal centrifugation condition. Plasma proteins in cryoprecipitate units were characterized on a STA Compact, Diagnostica STAGO and Siemens BCS analyzer.

RESULTS

Neither the centrifugation speed or time appeared to have an effect on the quality of the final cryoprecipitate product; however the initial solubilization of the cryoprecipitate product was found to be easier at the lower centrifugation setting (654 g for 2 min). Cryoprecipitate units prepared from Mirasol-treated plasma demonstrated protein levels that were less than levels in untreated products, but were on average 93 IU/unit, 262 mg/unit and 250 IU/unit for FVIII, fibrinogen and von Willebrand ristocetin cofactor activity, respectively.

CONCLUSION

Cryoprecipitate products prepared from Mirasol-treated plasma using a centrifugation method contain levels of fibrinogen, FVIII and von Willebrand ristocetin cofactor activity, that meet both the European and UK guidelines for untreated cryoprecipitate. Flexibility in centrifugation conditions should allow blood banks to use their established centrifugation settings to make cryoprecipitate from Mirasol-treated plasma.

Evaluation of the hemostatic potential including thrombin generation of three different therapeutic pathogen-reduced plasmas

BACKGROUND AND OBJECTIVES

Several pathogen inactivation methods currently applied to therapeutic plasma may result in products with different hemostatic properties. This study aims at evaluating and comparing the hemostatic potential of different therapeutic plasma preparations currently available in France.

MATERIALS AND METHODS

We studied three types of pathogen-reduced plasma for transfusion (MB/light, Amotosalen/UVA, industrial S/D plasma). Quarantine, non-pathogen-reduced plasma, was used as a control. This study compared more specifically the content in FVIII, fibrinogen (clottable and antigen assays) and ADAMTS-13 and evaluated the intrinsic hemostatic properties using a thrombin generation test [Calibrated Automated Thrombogram (CAT)] at high and low concentrations of tissue factor to assess the maximum quantity of thrombin generated or the contribution of FVIII and FIX in the amplification phase of thrombin generation, respectively.

RESULTS

The median FVIII concentration was >70 IU/dl for each preparation. Endogenous thrombin potential values were significantly different among the methods of plasma preparation (P<0·001) but were all in the range of the values measured in donors' plasma. Control by the thrombomodulin-activated protein C system was preserved in all preparations (>50% inhibition of endogenous thrombin potential). Fibrinogen concentrations were all within normal range but fibrinogen levels were lower in the plasmas treated with photochemical methods. ADAMTS-13 levels were preserved.

CONCLUSION

The hemostatic potential appears well preserved in all therapeutic plasmas tested but there are some differences between preparations, the clinical relevance of which remains to be elucidated.

Photochemical inactivation of Pseudomonas aeruginosa

Adaptability to a broad range of environments together with relatively high resistance to antibiotics and to disinfectants makes Pseudomonas aeruginosa a concern in hospitals and in public health. We investigated whether UVA-mediated photochemical inactivation of P. aeruginosa could be accomplished with high efficiency while at the same time preserving the sensitivity of subsequent diagnostic tests. We characterized dose responses and bactericidal kinetic rates of 5-iodonaphthyl 1-azide (INA) and of amotosalen (AMO) as these substances exposed to UVA are known to inactivate germs with minimal impact to blood products or to viral antigens. Neither UVA without photochemicals nor INA or AMO in the dark inactivated bacteria. We found that AMO was ca 1000-fold more effective in inactivating P. aeruginosa cells than INA under similar conditions. Photoinactivation with either INA or AMO at conditions that abolished bacterial infectivity did not impair polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) testing. For comparison, similar titers of Bacillus atrophaeus spores (a surrogate for B. anthracis) remained unaffected at conditions that reduced the survival of P. aeruginosa below detection levels. The results presented in this study should assist in improved methods to inactivate P. aeruginosa in environmental, clinical and forensic samples without impairing subsequent nucleic acid- or immune-based analysis.