Solvent/detergent treatment of human plasma--a very robust method for virus inactivation. Validated virus safety of OCTAPLAS

Unraveling the Biophysical Mechanisms of How Antiviral Detergents Disrupt Supported Lipid Membranes: Toward Replacing Triton X-100

Triton X-100 (TX-100) is a membrane-disrupting detergent that is widely used to inactivate membrane-enveloped viral pathogens, yet is being phased out due to environmental safety concerns. Intense efforts are underway to discover regulatory acceptable detergents to replace TX-100, but there is scarce mechanistic understanding about how these other detergents disrupt phospholipid membranes and hence which ones are suitable to replace TX-100 from a biophysical interaction perspective. Herein, using the quartz crystal microbalance-dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS) techniques in combination with supported lipid membrane platforms, we characterized the membrane-disruptive properties of a panel of TX-100 replacement candidates with varying antiviral activities and identified two distinct classes of membrane-interacting detergents with different critical micelle concentration (CMC) dependencies and biophysical mechanisms. While all tested detergents formed micelles, only a subset of the detergents caused CMC-dependent membrane solubilization similarly to that of TX-100, whereas other detergents adsorbed irreversibly to lipid membrane interfaces in a CMC-independent manner. We compared these biophysical results to virus inactivation data, which led us to identify that certain membrane-interaction profiles contribute to greater antiviral activity and such insights can help with the discovery and validation of antiviral detergents to replace TX-100.

Application of Formulation Principles to Stability Issues Encountered During Processing, Manufacturing, and Storage of Drug Substance and Drug Product Protein Therapeutics

The field of formulation and stabilization of protein therapeutics has become rather extensive. However, most of the focus has been on stabilization of the final drug product. Yet, proteins experience stress and degradation through the manufacturing process, starting with fermentaition. This review describes how formulation principles can be applied to stabilize biopharmaceutical proteins during bioprocessing and manufacturing, considering each unit operation involved in prepration of the drug substance. In addition, the impact of the container on stabilty is discussed as well.

Thrombotic microangiopathy in children

The syndrome of thrombotic microangiopathy (TMA) is a clinical-pathological entity characterized by microangiopathic hemolytic anemia, thrombocytopenia, and end organ involvement. It comprises a spectrum of underlying etiologies that may differ in children and adults. In children, apart from ruling out shigatoxin-associated hemolytic uremic syndrome (HUS) and other infection-associated TMA like Streptococcus pneumoniae-HUS, rare inherited causes including complement-associated HUS, cobalamin defects, and mutations in diacylglycerol kinase epsilon gene must be investigated. TMA should also be considered in the setting of solid organ or hematopoietic stem cell transplantation. In this review, acquired and inherited causes of TMA are described with a focus on particularities of the main causes of TMA in children. A pragmatic approach that may help the clinician tailor evaluation and management is provided. The described approach will allow for early initiation of treatment while waiting for the definitive diagnosis of the underlying TMA.

Solvent/Detergent-Treated Plasma in the Management of Pediatric Patients Who Require Replacement of Multiple Coagulation Factors: An Open-Label, Multicenter, Post-marketing Study

Background: Octaplas is a solvent/detergent-treated, pooled plasma used for the management of preoperative or bleeding patients who require replacement of single or multiple coagulation factors. The aim of this post-marketing study was to collect real-world data on octaplas treatment in pediatric patients, with the primary focus being safety. Methods: This was an open-label, multicenter, phase IV study conducted in patients <16 years old who required replacement of multiple coagulation factors due to liver dysfunction associated with coagulopathy and/or required cardiac surgery or liver surgery. Octaplas was administered intravenously based on ABO-group compatibility. The primary endpoints included the incidence of serious adverse events (SAEs), adverse drug reactions (ADRs), thrombotic events (TEs), thromboembolic events (TEEs) and hyperfibrinolytic events (HFEs). Results: A total of 50 patients were enrolled (≤2 years old, n = 37; >2 years old, n = 13; female, n = 24) and 49 patients completed the study. Indications for the use of octaplas included planned cardiac surgery (n = 40, 80.0%), liver transplant surgery (n = 5, 10.0%) and liver dysfunction (n = 5, 10.0%). No ADRs, HFEs or treatment-related TEs and TEEs occurred during the study. Five patients had SAEs, one of which was fatal (iatrogenic injury). Other SAEs included hemorrhage, hypotension, hemorrhagic shock, coronary artery hemorrhage, intracardiac thrombus, supraventricular tachycardia, portal vein thrombosis and respiratory failure (1 each). None of the SAEs were considered to be related to octaplas. Conclusions: Results of the present study support the use of octaplas in the management of preoperative or bleeding pediatric patients who require replacement of multiple plasma coagulation factors. Clinical Trial Registration: ClinicalTrials.gov identifier: NCT02050841.

Solvent detergent treated pooled plasma and reduction of allergic transfusion reactions

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) patients have increased risk for allergic transfusion reactions (ATR) due to the number of plasma products they require. This study evaluated the efficacy of solvent detergent treated plasma (S/D treated plasma) to reduce ATRs.

STUDY DESIGN AND METHODS

All TTP patients who presented from April 2014 to February 2015 and experienced a moderate-severe ATR to untreated plasma with TPE were switched to S/D treated plasma (Octaplas) for their remaining procedures and included in the study. Patient records were retrospectively reviewed.

RESULTS

The overall ATR rate per procedure decreased from 35.0% (95% CI = 15.4%-59.2%) with untreated plasma to 1.4% ([1/73] 95% CI = 0.0%-7.4%) with S/D treated plasma. The moderate-severe ATR rate decreased from 20.0% ([4/20] 95% CI = 5.7%-43.7%) with untreated plasma to 0.0% ([0/73] 95% CI = 0.0%-4.9%) with S/D treated plasma. The overall ATR rate per plasma unit decreased from 2.6% (95%CI = 1.0%-5.1%) with untreated plasma to 0.1% (95% CI = 0.0%-0.4%) with S/D treated plasma. No patients experienced VTE while receiving untreated plasma. Four patients experienced VTE events while receiving S/D treated plasma. All patients who experienced a VTE had additional risk factors for VTE.

CONCLUSION

S/D plasma has promise as an effective product to reduce the risk of ATRs in TTP patients. Given the high risk of ATR in TTP patients, consideration of S/D plasma instead of untreated plasma for TPE in these patients may be warranted, especially for patients with a history of moderate to severe ATR. More extensive studies are needed to confirm these findings.

Study on the immunological safety of universal plasma in the Chinese population in vitro

BACKGROUND

The prepared procedure for universal plasma in the Chinese population has been developed. However, the immunological safety with the level of antibodies, soluble immune complexes and complements is necessary to investigate.

METHODS

The universal plasma was pooled at the optimal ratio of A:B:AB=6:2.5:1.5 at 22°C for 1 hour. The titer of IgM antibodies was detected by saline agglutination, and the titer of IgG antibodies was detected by a Polybrene test after IgM destroyed by 2-mereaptoethanol. The hemolysis extent of RBC was investigated by an extracorporal hemolysis test, and the concentration of free-hemoglobin was determined by the ortho-tolidine method. The levels of CIC-C1q, C3b and TCC (C5-9) were tested using an enzyme linked immunosorbent assay (ELISA).

RESULTS

The titer of IgM and IgG in universal plasma was lower than 2 and 4, respectively. The hemolysis of the universal plasma with A, B and AB group RBCs was negative with values of 5.5, 6.8 and 5.7, respectively. The level of CIC-C1q and TCC (C5-9) in universal plasma was comparable to that in A or B type pooled plasma, but CIC-C1q was lower than that and TCC (C5-9) was higher than that in AB type pooled plasma. The level of complement C3b was comparable to that in A type pooled plasma, but lower than that in B type pooled plasma and higher than that in AB type pooled plasma.

CONCLUSION

The results of this study demonstrated that the immunological levels were within an acceptable range and confirmed the safety in vitro.

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.

The state of the art of removal of prion proteins in SD-FFP, by specific prion affinity chromatography and its impact on the hemostatic characteristics of the product

In recent Coimbra' Conference, on the pre-launch of pathogen reduced-FFP for the local clinical use, the question was raised, by the moderator, on the efficacy of the current methodology used for prion removal processes and its influence on the overall quality and safety of the final product. This brief paper put together by speaker of this session and the moderator, as a consensus of opinions, which was largely discussed during Q&A session, to make it available to a large group of readers of transfusion apheresis science, who might be interested to this topic. In short the capacity of the current process of Octaplas to remove prion is in order of 5.6 log10/ID50 reduction based on several animal studies. Moreover the changes in coagulation and inhibitors are within acceptable range and bioequivalent to untreated FFP with no sign of inferiority. This paper describes in brief a technology update on solvent/detergent treated plasma, an alternative to FFP but with increased pathogen safety. The biochemical profile of the final product is comparable with FFP and contains all clinically relevant plasma proteins. Furthermore, Octaplas is a product that, in long term, reduces health care costs.

[Therapeutic plasmas available worldwide]

Therapeutic plasma is a current product; French guidelines were reviewed in 2012. Connections between more or less closed countries are frequent, during relief disasters as well as in war settings. This is associated with the increasing use of plasma in the management of casualties. Additionally, The real possibility of lack of plasma supply in some countries provides a fundamental interest of the knowledge of foreign blood supply organizations. We present here the main divergences and mutual point between plasmas available worldwide. We present the main characteristics of each product.

A comparison of methods of pathogen inactivation of FFP

INTRODUCTION

Current methods for pathogen inactivation of plasma involve four major processes using solvent-detergent (SD), methylene blue (MB), amotosalen and riboflavin as additives. Three of these methods involve the use of visible or ultraviolet light.

METHODS

A comparison of the four methods was made using publications in Medline, Pubmed, Embase and Biosis to obtain data on the logistics of use, the quality of the plasma proteins and the effectiveness of pathogen inactivation.

RESULTS

Three of the methods, MB, amotosalen and riboflavin, are designed for use in a blood bank; the SD method is generally applied at a centralized manufacturing centre and involves large plasma pools. All methods result in a reduction in protein values with the per cent retention of FVIII activity in the range of 67-78% and fibrinogen of 65-84%. Protein S and alpha(2)-antiplasmin are lower following solvent-detergent treatment. Alterations in fibrinogen structure have been reported with methylene blue.

DISCUSSION

Three of the methods are designed for small volume use in a blood bank. All four methods have some effect on the coagulant proteins; however, the final concentrations are within regulated limits. While there is variability in the effectiveness against pathogens, direct comparison is difficult because of the methodologies used. Nonetheless, all are effective in inactivating HIV and other lipid-enveloped pathogens. Clinical studies on the effectiveness of these products are surprisingly sparse, and no randomized clinical trials have yet been performed with amotosalen or riboflavin plasmas.

The Use of Solvent/Detergent Treatment in Pathogen Reduction of Plasma

The solvent/detergent (SD) process used for plasma can safely inactivate all lipid-enveloped viruses. The introduction of a specific prion-binding ligand gel in combination with SD treatment, time-reduced from 4 to 1-1.5 h, still ensures efficient virus kill, reduces abnormal prion protein by >5 log steps, and preserves levels of plasmin inhibitor at close to the reference range. Infections with known non-enveloped viruses such as HAV or parvovirus B19 are prevented by ensuring low virus loads in the starting plasma units, dilution through pooling of single plasma units, and neutralization of immune antibodies already present in the initial plasma pools. The major advantages of SD plasma over fresh frozen plasma and the other pathogen-inactivated plasmas are its extreme safety with respect to transfusion-related acute lung injury and the significantly lower likelihood of provoking allergic reactions. Both advantages are best interpreted as results of the dilution effect of pooling. No fewer than 18 clinical studies covering all indications for plasma, and extensive clinical experience have shown that reduced levels of coagulation factors and inhibitors as a result of SD treatment do not impair significantly the clinical efficacy or tolerance of plasma. Properly standardized clotting factor and inhibitor potencies and low batch-to-batch variations when compared with single-donor plasma units makes SD plasma more suitable for standardized treatment.

Viral safety characteristics of Flebogamma DIF, a new pasteurized, solvent-detergent treated and Planova 20 nm nanofiltered intravenous immunoglobulin

A new human liquid intravenous immunoglobulin product, Flebogamma DIF, has been developed. This IgG is purified from human plasma by cold ethanol fractionation, PEG precipitation and ion exchange chromatography. The manufacturing process includes three different specific pathogen clearance (inactivation/removal) steps: pasteurization, solvent/detergent treatment and Planova nanofiltration with a pore size of 20 nm. This study evaluates the pathogen clearance capacity of seven steps in the production process for a wide range of viruses through spiking experiments: the three specific steps mentioned above and also four more production steps. Infectivity of samples was measured using a Tissue Culture Infectious Dose assay (log(10) TCID(50)) or Plaque Forming Units assay (log(10) PFU). Validation studies demonstrated that each specific step cleared more than 4 log(10) for all viruses assayed. An overall viral clearance between > or =13.33 log(10) and > or =25.21 log(10), was achieved depending on the virus and the number of steps studied for each virus. It can be concluded that Flebogamma DIF has a very high viral safety profile.

Emerging infectious disease agents and their potential threat to transfusion safety

BACKGROUND

Emerging infections have been identified as a continuing threat to human health. Many such infections are known to be transmissible by blood transfusion, while others have properties indicating this potential. There has been no comprehensive review of such infectious agents and their threat to transfusion recipient safety to date.

STUDY DESIGN AND METHODS

The members of AABB's Transfusion Transmitted Diseases Committee reviewed a large number of information sources in order to identify infectious agents with actual or potential risk of transfusion transmission now or in the future in the US or Canada; with few exceptions, these agents do not have available interventions to reduce the risk of such transmission. Using a group discussion and writing process, key characteristics of each agent were identified, researched, recorded and documented in standardized format. A group process was used to prioritize each agent on the basis of scientific/epidemiologic data and a subjective assessment of public perception and/or concern expressed by regulatory agencies.

RESULTS

Sixty-eight infectious agents were identified and are described in detail in a single Supplement to TRANSFUSION. Key information will also be provided in web-based form and updated as necessary. The highest priorities were assigned to Babesia species, Dengue virus, and vCJD.

CONCLUSION

The information is expected to support the needs of clinicians and transfusion medicine experts in the recognition and management of emerging infections among blood donors and blood recipients.

Proceedings of a Consensus Conference: pathogen inactivation-making decisions about new technologies

Significant progress has been made in reducing the risk of pathogen transmission to transfusion recipients. Nonetheless, there remains a continuing risk of transmission of viruses, bacteria, protozoa, and prions to recipients. These include many of the viruses for which specific screening tests exist as well as pathogens for which testing is currently not being done, including various species of bacteria, babesiosis, variant Creutzfeld-Jacob disease, hepatitis A virus, human herpes virus 8, chikungunya virus, Chagas disease, and malaria. Pathogen inactivation (PI) technologies potentially provide an additional way to protect the blood supply from emerging agents and also provide additional protection against both known and as-yet-unidentified agents. However, the impact of PI on product quality and recipient safety remains to be determined. The purpose of this consensus conference was to bring together international experts in an effort to consider the following issues with respect to PI: implementation criteria; licensing requirements; blood service and clinical issues; risk management issues; cost-benefit impact; and research requirements. These proceedings are provided to make available to the transfusion medicine community the considerable amount of important information presented at this consensus conference.

Normal levels of ADAMTS13 and factor H are present in the pharmaceutically licensed plasma for transfusion (Octaplas®) and in the universally applicable plasma (Uniplas) in development

BACKGROUND AND OBJECTIVES

The pathomechanism of thrombotic thrombocytopenic purpura (TTP) and atypical haemolytic uraemic syndrome (aHUS) is associated with a severe deficiency of ADAMTS13 and factor H. The aim of this study was to quantify the levels of ADAMTS13 and factor H in the pharmaceutically licensed plasma for transfusion, Octaplas, and the universally applicable plasma, Uniplas (development product, working title). Furthermore, Octaplas batches of blood groups A, B, O, AB, and plasmas derived from different sources were compared.

MATERIALS AND METHODS

Twenty-four Octaplas and three Uniplas batches were selected for the study. ADAMTS13 activities were measured by fluorescence resonance energy transfer assay, ADAMTS13 antigen levels were quantified using enzyme-linked immunosorbent assay test kit, while factor H antigen levels were detected using radial immunodiffusion (RID) methods. In addition, von Willebrand factor (vWF) multimeric analyses were performed.

RESULTS

Both Octaplas, produced from US and European plasma of different blood groups, and Uniplas contain ADAMTS13 antigen and activity levels as well as factor H concentrations at normal levels without significant differences. In addition, Octaplas and Uniplas show a vWF multimeric pattern comparable to normal plasma.

CONCLUSION

The study revealed that Octaplas and Uniplas contain normal levels of ADAMTS13 at low batch-to-batch variations. Therefore, both products can substitute the missing or neutralized protease activity in TTP patients and thereby limit vWF-dependent (platelet-related) thrombosis. In addition, both plasma products contain factor H at a physiological level, and, thus can be used efficiently in the treatment of aHUS patients, which have been shown to benefit from plasma administration.

A biochemical comparison of a pharmaceutically licensed coagulation active plasma (Octaplas®) with a universally applicable development product (Uniplas) and single-donor FFPs subjected to methylene-blue dye and white-light treatment

The strive for more standardised and highly efficacious products is one of the important mainstays in modern haemotherapy. Coagulation active plasma for transfusion is the product of choice when treating hereditary or acquired isolated or complex coagulopathies, when no specific concentrate is available. The aim of this study was to perform an extensive biochemical comparison of the pharmaceutically licensed coagulation active plasma named Octaplas with an identical, but universally applicable, development product (Uniplas, working title) and single-donor fresh-frozen plasma (FFP) units subjected to a medical device treatment using a combination of methylene-blue dye and subsequent white-light exposure (MB plasma). Our study showed that there are differences in the biochemical characteristics between Octaplas and MB plasma, while Uniplas revealed the same quality as Octaplas. The variability of selected plasma proteins in the 20 individual MB plasma units tested was high compared to Octaplas/Uniplas. Beyond the reported decreased levels of protein S and plasmin inhibitor found in Octaplas/Uniplas, and the significant loss of fully functional fibrinogen in MB plasma and its impact on selected global coagulation parameters, the latter product additionally revealed several coagulation factor activities outside the ranges given for normal single-donor FFP. It is important for plasma prescribers to be aware of the major inherent differences between Octaplas and MB plasma.

Universal pathogen-reduced plasma in elective open-heart surgery and liver resection

ABO-incompatible transfusions and transfusion-related lung injury are today the leading transfusion-related causes of death in the developed world. Since anti-A and anti-B antibodies in plasma can give rise to serious, even fatal, transfusion reactions, ABO-identical/compatible plasma is indicated, but presents a logistical challenge and a risk for transfusion of incorrect plasma. In an effort to circumvent these problems, an ABO-independent universally applicable, pathogen-reduced plasma, Uniplas, has been developed and proven safe and efficacious for use in adults through prospective, randomized, controlled open-heart surgery studies and in prospective, parallel group, controlled liver resection studies. The results of these trials are presented and discussed in relation to solvent/detergent (SD) treated plasma, in general. The cost effectiveness of pathogen-reduced plasma is low because of the very low risk for transfusion transmitted viral infections in the developed world (US 2 to 9 million dollars per quality-adjusted life year). However, taking into account the combined safety of Uniplas with regard to transfusion-related lung injury, pathogen reduction and independence of ABO blood groups, the cost per gained life year is reduced to US 40,000 dollars to 100,000 dollars.

Characterisation of a novel high-purity, double virus inactivated von Willebrand Factor and Factor VIII concentrate (Wilate)

This study summarises the biochemical and functional properties of a new generation plasma-derived, double virus inactivated von Willebrand Factor/Factor VIII (VWF/FVIII) concentrate, Wilate, targeted for the treatment of both von Willebrand disease (VWD) and haemophilia A. The manufacturing process comprises two chromatographic steps based on different performance principles, ensuring a high purity of the concentrate (mean specific activity in 15 consecutive production batches: 122 IU FVIII:C/mg total protein) and, thus, minimising the administered protein load to the patient (specification: < or = 15 mg total protein per 900 IU Wilate). The optimised solvent/detergent (S/D) treatment and prolonged terminal dry-heat (PermaHeat) treatment of the lyophilised product at a specified residual moisture (RM) provide two mechanistically independent, effective and robust virus inactivation procedures for enveloped viruses and one step for non-enveloped viruses. These process steps are aggressive enough to inactivate viruses efficiently, but yet gentle enough to maintain the structural integrity and function of the VWF and FVIII molecules, as proven by state-of-the-art assays covering the diverse features of importance. The VWF multimeric pattern is close to the one displayed by normal plasma, with a consistent content of more than 10 multimers, but a relatively lower portion of the very high multimers. The multimeric triplet structure is normal, underlining the gentle and effective manufacturing process, which does not require the addition of protein stabilisers at any step. The balanced activity ratio of VWF to FVIII is close to that of plasma from healthy subjects, rendering Wilate suitable also for the safe and effective treatment of patients with VWD.

Pathogen inactivation techniques

The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area of investigation. Clearly, regulatory agencies have a major role to play in the evaluation of these new technologies. This chapter will cover the several types of pathogen-reduction systems, mechanisms of action, the inactivation efficacy for specific types of pathogens, toxicology of the various systems and the published research and clinical trial data supporting their potential usefulness. Due to the nature of the field, pathogen reduction is a work in progress and this review should be considered as a snapshot in time rather than a clear picture of what the future will bring.

Stability of solvent/detergent-treated plasma and single-donor fresh-frozen plasma during 48h after thawing

The aim of this study was to compare the quality of solvent/detergent (SD) treated plasma, Octaplas, and single-donor fresh-frozen plasma (FFP) units during 48-h storage after thawing. Octaplas bags of different blood groups and individual FFP units were thawed and stored at either +4 degrees C or at room temperature (RT) for 48 h. Samples drawn during the observation period were investigated on various coagulation factor and protease inhibitor activities using standard coagulation and chromogenic assays. The generation of FVIIa was followed as a marker of coagulation factor activation. All investigated coagulation factors and protease inhibitors were stable for at least 8h during storage of Octaplas at +4 degrees C. FVIII levels started to decline earlier in FFP than in Octaplas at both storage temperatures. Stored Octaplas OD660 values were more stable during the storage period than FFP OD660 values, whereas VWF multimeric patterns were comparably stable in both types of plasma. In conclusion, this stability study has demonstrated that thawed Octaplas maintains its high quality, even with a time safety margin, for 8 h at +4 degrees C and for 6 h at RT. In general, there was more variability in coagulation factor levels among different FFP units compared with different Octaplas batches.

Plasma therapy in thrombotic thrombocytopenic purpura: review of the literature and the Bern experience in a subgroup of patients with severe acquired ADAMTS-13 deficiency

Based on clinical studies daily plasma exchange (PE) has become the first-choice therapy for thrombotic thrombocytopenic purpura (TTP) since 1991. Recent findings may explain its effectiveness, which particularly may include supply of ADAMTS-13 and removal of anti-ADAMTS-13 autoantibodies and unusually large von Willebrand factor (VWF) multimers. The most preferable PE regimens as well as replacement fluids are discussed and treatment-related adverse reactions are summarized. Proposals for a potential reduction of their frequency and for improvement of treatment efficiency are given. These suggestions are partially based on the experience of our institution in adult patients with severe ADAMTS-13 deficiency (<5% activity), and include (1) continuous calcium-gluconate infusion during PE in order to reduce citrate-related adverse reactions; (2) the evaluation of solvent/detergent-treated (S/D) plasma as replacement fluid in order to reduce adverse events due to fresh frozen plasma (FFP); (3) the evaluation of immunoadsorption in order to increase procedural efficiency in autoantibody removal; and (4) the substitution of ADAMTS-13 by means of recombinant drug instead of plasma.

Coagulation factor content of solvent/detergent plasma compared with fresh frozen plasma

Solvent/detergent (S/D) plasma is being increasingly widely used in clinical practice, as it carries significantly lower risk of lipid-enveloped viral transmission than standard fresh frozen plasma (FFP). However, previous reports have suggested that S/D processing might influence the coagulation factor content of plasma. We have investigated this question by measuring procoagulant factors (fibrinogen, factor V and factor VIII), anticoagulant factors (protein C and protein S) and routine coagulation screening tests (prothrombin time and activated partial thromboplastin time) in 48 single-donor units of FFP, and in 16 units of S/D plasma (Octaplas). All routine coagulation screening tests, factor VII and protein C levels were within the normal reference range for both S/D plasma and FFP. However, we found significant reductions in factor V (31%), factor VIII (28%) and protein S (50%) in S/D plasma. The observed quantitative differences in coagulation factor levels may be further exacerbated by the lower volume of solvent detergent plasma units (200 ml) compared with units of standard fresh frozen plasma (250 ml). These findings are of potential clinical significance, particularly in those patients with liver disease, constitutional factor V deficiency and congenital or acquired protein S deficiency.

Fibrinolysis during liver transplantation is enhanced by using solvent/detergent virus-inactivated plasma (ESDEP)

After the introduction of solvent/detergent-treated plasma (ESDEP) in our hospital, an increased incidence of hyperfibrinolysis was observed (75% vs 29%; P = 0.005) compared with the use of fresh frozen plasma for liver transplantation. To clarify this increased incidence, intraoperative plasma samples of patients treated with fresh frozen plasma or ESDEP were analyzed in a retrospective observational study. During the anhepatic phase, plasma levels of D-dimer (6.58 vs 1.53 microg/mL; P = 0.02) and fibrinogen degradation products (60 vs 23 mg/L; P = 0.018) were significantly higher in patients treated with ESDEP. After reperfusion, differences increased to 23.5 vs 4.7 microg/mL (D-dimer, P = 0.002) and 161 vs 57 mg/L (fibrinogen degradation products, P = 0.001). The amount of plasma received per packed red blood cell concentrate, clotting tests, and levels of individual clotting factors did not show significant differences between the groups. alpha(2)-Antiplasmin levels, however, were significantly lower in patients receiving ESDEP during the anhepatic phase (0.37 vs 0.65 IU/mL; P < 0.001) and after reperfusion (0.27 vs 0.58 IU/mL; P = 0.001). Analysis of alpha(2)-antiplasmin levels in ESDEP alone showed a reduction to 0.28 IU/mL (normal >0.95 IU/mL) because of the solvent/detergent process. Therapeutic consequences for the use of ESDEP in orthotopic liver transplantation are discussed in view of an increased incidence of hyperfibrinolysis caused by reduced levels of alpha(2)-antiplasmin in the solvent/detergent-treated plasma.

IMPLICATIONS

The use of solvent/detergent virus-inactivated plasma is of increasing importance in the prevention of human immunodeficiency virus and hepatitis C virus transmission. Since the use of this plasma during orthotopic liver transplantation has increased, the incidence of hyperfibrinolysis was observed. Clotting analysis of the patients revealed small alpha(2)-antiplasmin concentrations because of the solvent/detergent process.

Quantification of in vitro retroviral replication using a one-tube real-time RT-PCR system incorporating direct RNA preparation

The methodological and logistic benefits gained from assessing in vitro antiretroviral replication using one-tube real-time RT-PCR procedures are currently diminished by a continuing need for prior RNA isolation. We now report a simple and inexpensive modification of a commercially available one-tube RT-PCR assay, consisting of detergent-based virus lysis in the presence of a ribonuclease inhibitor, which can be used to directly quantify retroviral RNA levels in culture supernatant. This approach circumvents the potential loss of RNA inherent to RNA-isolation procedures based on prior extraction and demonstrates a dynamic range of at least 4 logs. Using in vitro culture systems incorporating either HIV-1 or FIV, we show that this ability to isolate retroviral RNA directly during the RT-PCR process can provide an equivalent alternative to one of the more time and resource-consuming steps in quantifying in vitro retroviral RNA levels.