The effect of methylene blue photoinactivation and methylene blue removal on the quality of fresh-frozen plasma

The Alterations in Methylene Blue/Light-Treated Frozen Plasma Proteins Revealed by Proteomics

Introduction

The aim of this study was to investigate the modified proteins in methylene blue/light-treated frozen plasma (MB-FP) compared with fresh frozen plasma (FFP) in order to gain a better application of MB/light-treated plasma in clinic transfusion.

Methods

MB-FP and FFP were collected from Changchun central blood station, and a trichloroacetic acid/acetone precipitation method was used to remove albumin for the enrichment of lower abundance proteins. The plasma protein in MB-FP and FFP were separated using two-dimensional gel electrophoresis (2-DE) and the differentially expressed protein spots were analyzed using mass spectrometry. Finally, the differentially expressed proteins were tested using Western blot and enzyme-linked immunosorbent assay (ELISA).

Results

Approximately 14 differentially expressed protein spots were detected in the MB-FP, and FFP was chosen as the control. After 2-DE comparison analysis and mass spectrometry, 8 significantly differentially expressed protein spots were identified, corresponding to 6 different proteins, including complement C1r subcomponent (C1R), inter-alpha-trypsin inhibitor heavy chain H4 (ITI-H4), keratin, type II cytoskeletal 1 (KRT1), hemopexin (HPX), fibrinogen gamma chain (FGG), and transthyretin (TTR). Western blot showed no significant difference in the expression level of KRT1 between MB-FP and FFP (p > 0.05). Both Western blot and ELISA indicated that the level of HPX was significantly higher in FFP than in MB-FP (p < 0.05).

Conclusion

This comparative proteomics study revealed that some significantly modified proteins occur in MB-FP, such as C1R, ITI-H4, KRT1, HPX, FGG, and TTR. Our findings provide more theoretical data for using MB-FP in transfusion medicine. However, the relevance of the data for the transfusion of methylene blue/light-treated plasma remains unclear. The exact modification of these proteins and the effects of these modified proteins on their functions and their effects in clinical plasma infusion need to be further studied.

Evaluation of the hemostatic capacity of methylene blue-treated liquid (not frozen) plasma stored up 14 days at 2° to 6°C

BACKGROUND

Early plasma transfusion for management of bleeding, particularly trauma, is associated with better outcomes. Improving the availability/safety of plasma transfusion for patients is essential for transfusion services. The aim of this study is to evaluate the hemostatic capacity of methylene-blue (MB) liquid (not frozen) plasma over time.

MATERIALS AND METHODS

Twenty whole blood-derived plasma units collected from male donors were separated and processed within 18 h of collection. Individual plasmas were treated with MB and stored in liquid status at 2-6°C for 14 days. A range of coagulation assays, including thrombin generation, rotational thromboelastometry (ROTEM), and Thrombodynamics were tested at different time-points, together with bacterial growth.

RESULTS

Apart from Factor (F)XII, other coagulation factors (fibrinogen, FV, FVIII, FXI) reduced significantly after MB treatment, with levels remaining stable except for FVIII afterward. By day 14, most clotting factors were >0.7 IU/ml, apart from FVIII. There was a disproportionate decrease in Protein S (PS) activity compared to free PS antigen and by day 14 its value was ~50%. There was no significant difference in maximum clot formation (ROTEM) and clot-density (Thrombodynamics) over time. Endogenous thrombin potential (Thrombin-Generation), clot-size, and velocity index (Thrombodynamics) decreased significantly over time consistent with clotting factor reduction. There was no bacterial growth.

CONCLUSIONS

MB-treated liquid plasma stored at 2-6°C can be used for up to 14 days: the long shelf-life, the liquid status, and the MB treatment will improve its availability for management of bleeding as well as providing a safe component from pathogens.

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.

Pathogen reduction in human plasma using an ultrashort pulsed laser

Pathogen reduction is a viable approach to ensure the continued safety of the blood supply against emerging pathogens. However, the currently licensed pathogen reduction techniques are ineffective against non-enveloped viruses such as hepatitis A virus, and they introduce chemicals with concerns of side effects which prevent their widespread use. In this report, we demonstrate the inactivation of both enveloped and non-enveloped viruses in human plasma using a novel chemical-free method, a visible ultrashort pulsed laser. We found that laser treatment resulted in 2-log, 1-log, and 3-log reductions in human immunodeficiency virus, hepatitis A virus, and murine cytomegalovirus in human plasma, respectively. Laser-treated plasma showed ≥70% retention for most coagulation factors tested. Furthermore, laser treatment did not alter the structure of a model coagulation factor, fibrinogen. Ultrashort pulsed lasers are a promising new method for chemical-free, broad-spectrum pathogen reduction in human plasma.

Factor VIII and fibrinogen recovery in plasma after Theraflex methylene blue-treatment: effect of plasma source and treatment time

BACKGROUND

The quality of fresh-frozen plasma is affected by different factors. Factor VIII is sensitive to blood component storage processes and storage as well as pathogen-reduction technologies. The level of fibrinogen in plasma is not affected by the collection processes but it is affected by preparation and pathogen-reduction technologies.

MATERIALS AND METHODS

The quality of plasma from whole blood and apheresis donations harvested at different times and treated with a pathogen-reduction technique, methylene blue/light, was investigated, considering, in particular, fibrinogen and factor VIII levels and recovery.

RESULTS

The mean factor VIII level after methylene blue treatment exceeded 0.5 IU/mL in all series. Factor VIII recovery varied between 78% and 89% in different series. The recovery of factor VIII was dependent on plasma source as opposed to treatment time. The interaction between the two factors was statistically significant. Mean levels of fibrinogen after methylene blue/light treatment exceeded 200 mg/dL in all arms. The level of fibrinogen after treatment correlated strongly with the level before treatment. There was a negative correlation between fibrinogen level before treatment and recovery. Pearson's correlation coefficient between factor VIII recovery and fibrinogen recovery was 0.58.

DISCUSSION

These results show a difference in recovery of factor VIII and fibrinogen correlated with plasma source. The recovery of both factor VIII and fibrinogen was higher in whole blood plasma than in apheresis plasma. Factor VIII and fibrinogen recovery did not appear to be correlated.

[The different types of therapeutic plasma are equivalent?]

In France, three varieties of therapeutic plasma are being processed, distributed and delivered, currently; however, many more varieties are in use worldwide, which go by the property of labile blood component or plasma derived medicines. For one type of component (one given name), several devices and bags and so on are used to concur to its process, which makes that one type of therapeutic plasma may significantly differ from one production setting to one other. This may affect (more or less) the component properties as well as the possibly reported adverse events. This review aims thus, firstly at stressing on the difficulty in comparing data obtained in different contexts, and secondly at making the point on future directions to process therapeutic plasma.

Virus-inactivated plasma - Plasmasafe: a one-year experience

BACKGROUND

Fresh-frozen plasma (FFP) is a widely used blood transfusion product. The transfusion safety of this product is ensured by legally obligatory tests, but can be further improved by using some technical procedures, such as methylene blue (MB) and solvent-detergent (SD) viral inactivation methods. Mainly organisational criteria led us to introduce the SD viral inactivation technique as a service activity. In this report we describe our first year of experience, following the introduction of the SD technique, and thus the use of SD-virally inactivated plasma (PlasmaSafe).

MATERIALS AND METHODS

IN ORDER TO EVALUATE THE APPROPRIATE USE AND THE THERAPEUTIC EFFICACY OF PLASMASAFE IN OUR BLOOD TRANSFUSION UNIT, THE FOLLOWING PROGRAMME WAS PLANNED: quality control [prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen] of the FFP units (N=312); evaluation of the clinical effectiveness on 490 patients (879 transfusion events); pre- and post-treatment monitoring of indicators of coagulation (PT, aPTT, fibrinogen, proteins S and C, factor VIII) on 15 patients; treatment of three patients with thrombotic thrombocytopenic purpura (TTP) undergoing plasma-exchange; haemovigilance of adverse reactions provoked by SD-plasma.

RESULTS

THE INDICATORS OF COAGULATION IN THE FFP UNITS VARIED GREATLY: the PT ranged from 50-120%, the aPTT from 24-41 seconds and the fibrinogen concentration from 1.42-6.84 g/L. Seventy-six percent of the patients responded to the plasma administration; moreover, two of 15 patients in whom protein S was assayed, showed no increase of this haemostatic protein. The TTP patients responded to plasma exchange treatment following four sessions of apheresis. During the observation period 8,422 PlasmaSafe units were transfused and no adverse reactions were recorded.

CONCLUSION

PlasmaSafe, a pharmaceutical-like product with a standardised content of coagulation factors, was found to be effective at correcting coagulation defects and for treating TTP. No thrombotic complications or transfusion-related adverse reactions were recorded.

Storage of thawed plasma for a liquid plasma bank: impact of temperature and methylene blue pathogen inactivation

BACKGROUND

Rapid transfusion of fresh-frozen plasma (FFP) is desired for treating coagulopathies, but thawing and issuing of FFP takes more than 40 minutes. Liquid storage of plasma is a potential solution but uncertainties exist regarding clotting factor stability. We assessed different storage conditions of thawed FFP and plasma treated by methylene blue plus light (MB/light) for pathogen inactivation.

STUDY DESIGN AND METHODS

Fifty thawed apheresis plasma samples (approx. 750 mL) were divided into three subunits and either stored for 7 days at 4°C, at room temperature (RT), and at 4°C after MB/light treatment. Clotting factor activities (Factor [F] II, FV, FVII through FXIII, fibrinogen, antithrombin, von Willebrand factor antigen, Protein C and S) were assessed after thawing and on Days 3, 5, and 7. Changes were classified as "minor" (activities within the reference range) and "major" (activities outside the reference range).

RESULTS

FFP storage at 4°C revealed major changes for FVIII (median [range], 56% [33%-114%]) and Protein S (51% [20%-88%]). Changes were more pronounced when plasma was stored at RT (FVIII, 59% [37%-123%]; FVII, 69% [42%-125%]; Protein S, 20% [10%-35%]). MB/light treatment of thawed FFP resulted in minor changes. However, further storage for 7 days at 4°C revealed major decreases for FVIII (47% [12%-91%]) and Protein S (49% [18%-95%]) and increases for FVII (150% [48%-285%]) and FX (126% [62%-206%]).

CONCLUSION

Storage of liquid plasma at 4°C for 7 days is feasible for FFP as is MB/light treatment of thawed plasma. In contrast, storage of thawed plasma for 7 days at RT or after MB/light treatment at 4°C affects clotting factor stability substantially and is not recommended.

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.

Main Properties of the THERAFLEX MB-Plasma System for Pathogen Reduction

Methylene blue (MB) treated plasma has been in clinical use for 18 years. The current THERAFLEX MB-Plasma has a number of improved features compared with the original Springe methodology. This overview embodies: the biochemical characteristics of MB, the mechanism of the technology, toxicology, pathogen reduction capacity, current position in clinical setting and status within Europe. The THERAFLEX MB (TMB) procedure is a robust, well standardised system lending itself to transfusion setting and meets the current guidelines. The pathogen kill power of the TMB system, like the other available technologies, is not limitless, probably in order of 6 log for most enveloped viruses and considerably less for non-enveloped ones. It does not induce either new antigen or grossly reducing the function and life span of active principle in fresh frozen plasma (FFP). The removal of the residual MB at the end of the process has the beneficial effect of reducing potential toxic impacts. Clinical haemovigilance data, so far, indicate that cell-free MB plasma is effective in all therapeutic setting requiring FFP, besides inconsistent thrombotic thrombocytopenia purpura data, without serious side-effects or toxicity. The current system is in continuous improvement e.g. regarding virus reduction range, illumination device, software used, and process integration in the blood bank setting.

UVC Irradiation for Pathogen Reduction of Platelet Concentrates and Plasma

Besides the current efforts devoted to microbial risk reduction, pathogen inactivation technologies promise reduction of the residual risk of known and emerging infectious agents. A novel pathogen reduction process for platelets, the THERAFLEX UV-Platelets system, has been developed and is under clinical evaluation for its efficacy and safety. In addition, proof of principle has been shown for UVC treatment of plasma units. The pathogen reduction process is based on application of UVC light of a specific wavelength (254 nm) combined with intense agitation of the blood units to ensure a uniform treatment of all blood compartments. Due to the different absorption characteristics of nucleic acids and proteins, UVC irradiation mainly affects the nucleic acid of pathogens and leukocytes while proteins are largely preserved. UVC treatment significantly reduces the infectivity of platelet units contaminated by disease-causing viruses and bacteria. In addition, it inactivates residual white blood cells in the blood components while preserving platelet function and coagulation factors. Since no photoactive compound needs to be added to the blood units, photoreagent-related adverse events are excluded. Because of its simple and rapid procedure without the need to change the established blood component preparation procedures, UVC-based pathogen inactivation could easily be implemented in existing blood banking procedures.

Pathogen inactivation in fresh frozen plasma using riboflavin and ultraviolet light: Effects on plasma proteins and coagulation factor VIII

Background/Aim. Riboflavin (vitamin B2) activated by ultraviolet (UV) light, produces active oxygen which damages cell membrane and prevents replication of the carrier of diseases (viruses, bacteria, protozoa) in all blood products. The aim of this study was to establish the influence of the process of photo inactivation in pathogens using riboflavin and UV rays on the concentration of coagulation factor VIII:C (FVIII:C) and proteins in plasma that were treated before freezing. Methods. The examination included 20 units of plasma, separated from whole blood donated by voluntary blood donors around 6 hours from the moment of collection. The units were pooled and separated in to two groups: one consisted of 10 control units and the other of 10 experimental units. Experimental units of the plasma were treated by riboflavin (35 mL) and UV rays (6.24 J/mL, 265-370 nm) on Mirasol aparature (Caridian BCT Biotechnologies, USA) in approximate duration of 6 minutes. Furthermore, 35 mL of saline solution was added to the control plasma. One sample for examining was taken from the control plasma (KG) and two residual were taken from experimental plasma after the addition of riboflavin either before (EG1) or post illumination (EG2). Results. Comparing the mean values of FVIII:C (%) we noticed statistically significantly higher level in the EG1 group than in the EG2 group (65.00 ? 4.52 vs 63.20 ? 4.73; t = 4.323, p = 0.002), while between the KG and experimental groups (EG1 and EG2) there was no statistically significant difference in the concentration of FVIII:C. There was a statistically significant decrease of albumin concentration (g/L) in the EG2 group comparing to the KG (33.35 ? 0.94 vs 31.94 ? 0.84; t = 3.534, p = 0.002), but there was no mentioned difference in albumin concentration between the KG and the EG1, so as between the EG1 and the EG2. Conclusion. Plasma inactivated by riboflavin and UV rays (Mirasol PRT sistem, Caridian BCT, USA) keeps all the characteristics of conventional plasma, so it could be used for the treatment of pathological conditions that demand transfusion of fresh frozen plasma, or in patients with thrombotic thrombocytopenic purpure when we use therapeutic exchange of plasma.

Characteristics of prion-filtered red cells suspended in pathogen-inactivated plasma (MB treated or solvent-detergent treated) for neonatal exchange transfusion

BACKGROUND AND OBJECTIVES

Neonates undergoing exchange transfusion require <5-day-old red cells suspended in plasma. This study assesses the effect of replacing the saline, adenine, glucose and mannitol (SAGM) of prion reduced (P-Capt) red cells with either methylene blue-treated plasma (MBTFFP) or OctaplasLG to reduce the risk of variant Creutzfelt-Jakob disease transmission.

MATERIALS AND METHODS

Twenty leucoreduced red cell units in SAGM were prion reduced on day 1. The SAGM was replaced by MBTFFP (n=10) or OctaplasLG (n=10). The units were irradiated and stored at 4°C for 24 h. A further 20 units were stored for 5 days before being processed as above. Haemolysis (%), potassium, ATP, 2,3-DPG and plasma proteins were measured.

RESULTS

Haemolysis remained low (≤0·16%). Following irradiation and storage, red cells in both types of plasma showed similar changes in potassium and ATP concentrations. The 2,3-DPG concentrations were well maintained although lower in red cells in OctaplasLG compared with those in MBTFFP (4·79 vs. 6·83 μmoles/g Hb on day 6). MBTFFP contained lower concentrations of fibrinogen, FV and FVIII. In OctaplasLG, alpha-2-antiplasmin was approximately 0·4 U/ml lower than in MBTFFP. After 24 h at 4°C, free protein S in OctaplasLG fell from 0·82 to 0·57 IU/ml. Other plasma proteins, in both types of plasma, were stable.

CONCLUSIONS

Red cells in both types of plasma demonstrated similar storage characteristics. The plasma proteins, except protein S in OctaplasLG, were stable over 24 h at 4°C in both types of plasma, and low FVIII concentrations were noted in the MBTFFP (group O) units used.

The influence of riboflavin photochemistry on plasma coagulation factors

Studies with riboflavin in the 1960s showed that it could be effective at inactivating pathogens when exposed to light. The principal mode of action is through electron transfer reactions, most importantly in nucleic acids. This suggested that it could act as a photosensitizer useful in the inactivation of pathogens found in blood products.

OBJECTIVE

To study the influence of photo-inactivation with riboflavin on the coagulation factors of plasma.

METHODS

The photo-inactivation procedure of riboflavin plus light was applied. Fifty isogroup pools of two plasmas were made from 100U of plasma that were derived from whole blood products that had previously been held overnight. Pools were split into two bags. One of them was photo-inactivated, and post inactivation samples were obtained. The second bag was not photo-inactivated and samples were taken. Total protein, fibrinogen, FII, FV, FVII, FVIII, FIX, FX, FXI, FXIII, antithrombin III, PC, PS, alpha-2 antiplasmin and vWF:Ag, the multimeric structure of vWF and ADAMTS-13 were analyzed.

RESULTS

In plasma, the proteins most sensitive to photo-inactivation were fibrinogen, FXI, FVIII, FV, and FIX (33%, 32%, 30%, 18% and 18% loss, respectively). Coagulation inhibitors, PS, antithrombin III and PC showed little decrease (all 2%). Retention of vWF and ADAMTS-13 were 99% and 88%, respectively.

CONCLUSIONS

As with other pathogen reduction procedures for plasma products, treatment with riboflavin and UV light resulted in reduction in the activity levels of several pro-coagulant factors. Coagulation inhibitors are well preserved.

Thrombin Generation Capacity of Methylene Blue-Treated Plasma Prepared by the Theraflex MB Plasma System

BACKGROUND: Methylene blue (MB) / light treatment is a well-known procedure for the inactivation of pathogens in fresh frozen plasma (FFP). Aim of the current study was to investigate the thrombin generation (TG) characteristics and quality of MB plasma prepared by the Theraflex MB Plasma System. METHODS: Single donor plasma units (n = 18) were MB/light-treated, with sampling before and after processing. Preparation included leukocyte depletion, addition of MB pill prior to illumination, and depletion of MB and photoproducts by filtration. Different plasma parameters and TG were measured. TG additionally was determined in solvent/detergent plasma (n = 8). RESULTS: MB/light treatment significantly affected factors V, VIII and XI, which were decreased by 9-18%. While the antigen level was not affected, fibrinogen according to Clauss was decreased by 7%, correlating with a 12% prolongation of TT and RT. The total amount of free thrombin generated, given as 'area under the curve' (AUC), was comparable for untreated (93 +/- 18% of normal plasma) and MB/light-treated plasma (95 +/- 20%). Also peak thrombin concentration was not significantly affected by treatment (94 +/- 11% (untreated) vs. 96 +/- 12% (treated)). The 'time to peak' value (TTP) was 105% of normal plasma for untreated FFP and 89% for MB-treated plasma. CONCLUSION: For plasma treated with the Theraflex MB Plasma System no profound influence of MB/ light treatment on the characteristics of thrombin generation was detected. In concordance with data from the literature, coagulation factors V, VIII and XI were decreased due to MB/ light treatment. Decrease was less than 20%.

Thrombin generation and clot formation in methylene blue-treated plasma and cryoprecipitate

BACKGROUND

Methylene blue (MB) treatment of plasma is known to reduce the activity of clotting factors, but its effect on thrombin generation and clot formation is not well documented.

STUDY DESIGN AND METHODS

Individual clotting factors and inhibitors and global tests of thrombin generation and clot formation using rotational thrombelastometry (ROTEM) were assessed in a paired study of standard or MB plasma and cryoprecipitate (n = 20 each).

RESULTS

MB treatment resulted in a 10 percent reduction in endogenous thrombin potential and 30 percent decrease in peak thrombin as well as the expected 20 to 35 percent loss of Factor (F)VIII, fibrinogen, and FXI activity. MB treatment had no effect on the rate of clot formation and increased the clot firmness by 20 percent as assessed by ROTEM. There were minimal further changes in either coagulation factor levels or thrombin generation when thawed plasma was stored for an additional 24 hours. FVIII and fibrinogen content of MB cryoprecipitate was reduced by 30 and 40 percent, respectively, but this was not associated with altered clot time or rate of clot formation by ROTEM and only an 8 percent decrease in clot firmness.

CONCLUSIONS

It is concluded that MB treatment is associated with a reduction in the thrombin-generating capacity of plasma, but has very little effect on the strength of clot formation as assessed by thrombelastometry. The thrombin-generating capacity of standard and MB plasma is relatively unaltered by subsequent storage of thawed plasma at 4 degrees C for 24 hours.

Coagulation function in fresh-frozen plasma prepared with two photochemical treatment methods: methylene blue and amotosalen

BACKGROUND

Pathogen inactivation of plasma intended for transfusion is now the standard of care in Belgium. Two methods for treatment of single plasma units are available: amotosalen plus ultraviolet A light and methylene blue plus visible light. This study compared the quality and stability of plasma treated with these two methods.

STUDY DESIGN AND METHODS

Plasma units made from a pool of two ABO-matched fresh apheresis units were photochemically treated with either amotosalen (PCT-FFP) or methylene blue (MB-FFP). A total of 12 paired samples were evaluated. Plasma coagulation function was assessed at three time points: immediately after treatment, after 30 days of frozen storage, and an additional 24 hours at 4 degrees C after thawing. Comparison between PCT-FFP and MB-FFP was assessed with the paired t test and a p value of less than 0.05 indicated statistical significance.

RESULTS

Based on statistical analysis, mean levels of factor (F)II, FXII, FXIII, von Willebrand antigen, ADAMTS-13, D-dimers, and protein C were equivalent between PCT-FFP and MB-FFP for all three time points. PCT-FFP exhibited shorter mean prothrombin time, activated partial thromboplastin time (two time points), and thrombin time and higher mean levels of fibrinogen, FXI, and protein S than MB-FFP. Retention of FV, FVII, FVIII, FX, or von Willebrand factor:ristocetin cofactor in PCT-FFP was either equivalent to or higher than MB-FFP. MB-FFP contained higher mean levels of plasminogen, antithrombin, and plasmin inhibitor than PCT-FFP. Retention of F IX in MB-FFP was higher than PCT-FFP only after the 4 degrees C storage after thawing.

CONCLUSION

There is adequate preservation of therapeutic coagulation factor activities in both PCT-FFP and MB-FFP. The overall coagulation factor levels and stability of PCT-FFP were better preserved than MB-FFP.

Quality and safety of fresh-frozen plasma inactivated and leucoreduced with the Theraflex methylene blue system including the Blueflex filter: 5 years' experience

BACKGROUND AND OBJECTIVES

The objective of this paper is to present 5 years' experience of pathogen inactivation of fresh-frozen plasma with the methylene blue system in a blood centre in Athens.

MATERIALS AND METHODS

Eight thousand and five hundred units treated by methylene blue and 54 435 untreated were issued for transfusion in four hospitals during the period 2000-2005. Eighty-eight units were evaluated for changes in coagulation factor activity and cytokine concentrations following treatment.

RESULTS

Coagulation factor losses were in the accepted range. Adverse reactions were 1 : 8500 with treated and 1 : 2177 with untreated units. The five serious reactions were all in untreated units. No seroconversions for infectious diseases were reported.

CONCLUSIONS

Methylene-blue-treated fresh-frozen plasma is safer than the untreated product even in patients who require large quantities of plasma transfusion.

The evidence-based use of FFP and cryoprecipitate for abnormalities of coagulation tests and clinical coagulopathy

There continues to be a general but unfounded enthusiasm for fresh frozen plasma (FFP) or frozen plasma (FP) usage across a range of clinical specialties in hospital practice. Plasma for transfusion is most often used where there are abnormal coagulation screening tests, either therapeutically in the face of bleeding, or prophylactically in nonbleeding patients prior to invasive procedures or surgery. Little evidence exists to inform best therapeutic transfusion practice, and most studies describe plasma use in a prophylactic setting. Laboratory abnormalities of coagulation are considered by many clinicians to be a predictive risk factor for bleeding prior to invasive procedures or in other clinical situations where bleeding risk exists, and plasma for transfusion is presumed to improve the laboratory results and reduce this risk. However, most guideline indications for the prophylactic use of plasma for transfusion are not supported by evidence from good-quality randomized trials. Arguably, the strongest randomized controlled trial (RCT) evidence indicates that prophylactic plasma for transfusion is not effective across a range of different clinical settings, and this is supported by data from nonrandomized studies in patients with mild to moderate abnormalities in coagulation tests. There is a need to undertake new trials evaluating the efficacy and adverse effects of plasma, both in bleeding and non-bleeding patients, to understand whether the presumed benefits outweigh the real risks. In addition, new hemostatic tests that better define the risk of bleeding and monitor the effectiveness of the use of FFP should be validated. Last, there is an opportunity to develop effective educational strategies aimed at addressing understanding and compliance with recommendations in guidelines.

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.

Pathogen-reduction systems for blood components: The current position and future trends

The current multi-layered interventional approaches to blood safety have dramatically reduced the risk of viral contamination of blood components. Nowadays most of the residual transfusion transmitted infections (TTI) occur as the result of the interval between the time the donor is infected and the moment at which tests are capable of detecting the agent, the so called "window period" which has been considerably reduced by the increased sensitivity of nucleic acid testing (NAT). However, the residual risk of bacterial contamination and the unexpected appearance of some other emerging pathogens, almost every five years, are still of major concern to the public, politicians, regulatory agencies and place immense pressures on the organisations responsible for the provision of safe blood and its components. In view of these bleak scenarios, the use of human blood as a raw biological source is inherently unsafe, and screening/testing alone cannot exclude all the potential human pathogens; hence we need to put in place some sort of safer alternatives and/or additional preventative safety measures. Recently, several substitutes (alternatives) to virtual blood components have been developed and tried. Moreover, various mechanical methods such as cell washing and leukofiltration have been implemented as additional preventative safety measures but with limited success in abrogating the risk of transfusion transmitted cell-associated agents. The most promising approaches, so far, are methods that target pathogen nucleic acids (Methylene blue; Psolaren and Riboflavin UV light treatment). These procedures have undergone considerable in vitro studies to ensure their extremely high safety margins in terms of toxicity to the cells or to the recipients. In essence, while the technology of targeting nucleic acid to stop viral proliferation is common to the above three strategies, in practice these procedures differ in terms of operational, physicochemical and biological characteristics; including the potential impacts of their metabolites and photo-adducts; their effects on the spectrum of pathogens affected and the log reductions in culture infective studies. Accordingly, any strategy that involves addition of an extraneous agent or physicochemical manipulation of blood must balance the benefits of pathogen reduction against the loss or alteration to the cells and plasma functional integrity, short and long term toxicity to the cells and to the recipients, as well as the risk to the personnel involved and the community at large. Moreover, it must be noted that each method will have a different profile of adverse reactions and may differ in terms of the risk to particularly vulnerable groups of patients, requiring in depth clinical trials, while taking into consideration the cost benefit of the final process. Newer diagnostic procedures must be in place to establish the storage stability of products that have undergone pathogen inactivation, in particular tests reflecting the release of platelet-derived cytokines, cellular apoptosis or microvesiculation and their role in immunosupressiveness. This overview aims to provide an update on the continual improvements in blood component safety, in particular using methods that target pathogen nucleic acid. Emphasis is placed on methylene blue light treatment (MBLT) and Intercept or Mirasol PRT systems for platelets and plasma. The status of pathogen reduction of whole blood and red cells is also highlighted, though the progress in this area has been virtually stopped after the finding of antibody development in the clinical trial.

The influence of methylene blue light treatment and methylene blue removal filter on fibrinogen activity states and fibrin polymerisation indices

BACKGROUND/OBJECTIVE

Methylene blue light treatment (MBLT) is efficient in inactivating viruses in plasma. However, it may cause alterations in clotting factors, especially fibrinogen (Fg). The true mechanism of such a selective alteration is poorly understood, The effects of MBLT and MB removal filters (MBRF) on Fg concentration, functional activity and fibrin polymerisation were studied.

DESIGN

Apheresis plasma collected by Haemonetic MCS Plus (n=10) was split into two equal aliquots. Both were leukofiltered and virally inactivated in a standardized fashion, using Theraflex MB-Plasma Photodynamic viral inactivation Macopharma method. One of the pair was subsequently processed, using Blueflex MBRF to remove residual MB and its by-products. Control plasma samples were obtained after filtration but before MBLT. Samples were also obtained after MBLT and MBRF. All samples were analyzed for the Fg activity, Fg antigen, thrombin clotting time (TT), and alterations fibrin polymerisation indices.

RESULTS

After MBLT, mean Fg concentration increased slightly (2%) whereas functional activity decreased by 31%, as compared to control samples. Mean TT prolonged by 6s after MBLT, with no further changes after MBRF. A similar trend was observed using RT. Both thrombin and reptilase triggered fibrin polymerisation were delayed and the polymerisation curves slopes were decreased slightly, with concomitant changes in fibrin opacity in samples from MBLT and MBRF as compared to control. Comparison is made for the first time with a similar changes observed in dysfibrinogenemia.

CONCLUSION

MBLT resulted in about 30% decrease in Fg activity but a slight modification in fibrin polymerisation indices, with no additional alteration subsequent to MBRF. These in vitro changes are similar to those seen in plasma from patients with dysfibrinogenemia, which are usually without clinical significance.

Fresh frozen plasma prepared with amotosalen HCl (S-59) photochemical pathogen inactivation: transfusion of patients with congenital coagulation factor deficiencies

BACKGROUND

Photochemical treatment (PCT) with amotosalen HCl (S-59) was developed to inactivate pathogens and white blood cells in plasma (PCT-FFP) used for transfusion support.

STUDY DESIGN AND METHODS

An open-label, multicenter trial was conducted in patients with congenital coagulation factor deficiencies (factors [F]I, FII, FV, FVII, FX, FXI, and FXIII and protein C) to measure the kinetics of specific coagulation factors, hemostatic efficacy, and safety of PCT-FFP. Posttransfusion prothrombin time (PT), partial thromboplastin time (PTT), and clinical hemostasis were evaluated before and after PCT-FFP transfusions.

RESULTS

Thirty-four patients received 107 transfusions of PCT-FFP for kinetic studies or therapeutic indications (mean dose, 12.8 +/- 8.5 mL/kg). Incremental factor recoveries ranged from 0.9 to 2.4 IU per dL per IU per kg (FII, FV, FVII, FX, FXI, and protein C). Mean pretransfusion PT (20.7 +/- 22.2 sec) corrected after PCT-FFP (13.8 +/- 2.4 sec, p < 0.001). Mean pretransfusion PTT (51.2 +/- 29.3 sec) corrected after PCT-FFP (32.0 +/- 5.1 sec, p < 0.001). Thirteen patients required 77 transfusions for therapeutic indications. PCT-FFP provided effective hemostasis and was well tolerated.

CONCLUSIONS

Replacement coagulation factors in PCT-FFP exhibited kinetics and therapeutic efficacy consistent with conventional FFP.

Cryoprecipitate prepared from plasma treated with methylene blue plus light: increasing the fibrinogen concentration

When cryoprecipitate is prepared from plasma which has been treated with methylene blue plus light (MB) for the purpose of virus inactivation, clottable fibrinogen content is 40% lower compared with units prepared from untreated plasma. Initial studies showed that when frozen MB plasma units were removed to +2 to +6 degrees C for 4 h and then returned to -40 degrees C prior to cryoprecipitation, fibrinogen recoveries increased from 24 to 42%. Although fibrinogen yield improved when plasma units were stored at +2 to +6 degrees C for varying lengths of time, FVIII levels decreased with increasing time. Conditioning for 8 h was studied in more detail. Groups of two plasma units were mixed together, divided into two equal units, frozen/thawed and treated with MB. One of each pair was stored continually at -40 degrees C, whereas the other was removed to +2 to +6 degrees C for 8 h. Samples were assayed for fibrinogen, FVIII, VWF:Ristocetin cofactor activity (RCo), VWF:Ag and VWF:Collagen binding (CB). The cryoprecipitate fibrinogen content increased to a mean of 207 mg unit(-1). VWF:Ag, VWF:RCo and VWF:CB recoveries also increased. FVIII recovery decreased from 50 to 45% (mean 124 iu unit(-1)). Conditioning has been validated for routine production of cryoprecipitate from imported plasma.

Guidelines for the use of fresh-frozen plasma, cryoprecipitate and cryosupernatant

The indications for transfusing fresh-frozen plasma (FFP), cryoprecipitate and cryosupernatant plasma are very limited. When transfused they can have unpredictable adverse effects. The risks of transmitting infection are similar to those of other blood components unless a pathogen-reduced plasma (PRP) is used. Of particular concern are allergic reactions and anaphylaxis, transfusion-related acute lung injury, and haemolysis from transfused antibodies to blood group antigens, especially A and B. FFP is not indicated in disseminated intravascular coagulation without bleeding, is only recommended as a plasma exchange medium for thrombotic thrombocytopenic purpura (for which cryosupernatant is a possible alternative), should never be used to reverse warfarin anticoagulation in the absence of severe bleeding, and has only a very limited place in prophylaxis prior to liver biopsy. When used for surgical or traumatic bleeding, FFP and cryoprecipitate doses should be guided by coagulation studies, which may include near-patient testing. FFP is not indicated to reverse vitamin K deficiency for neonates or patients in intensive care units. PRP may be used as an alternative to FFP. In the UK, PRP from countries with a low bovine spongiform encephalopathy incidence is recommended by the Departments of Health for children born after 1 January 1996. Arrangements for limited supplies of single donor PRP of non-UK origin are expected to be completed in 2004. Batched pooled commercially prepared PRP from donors in the USA (Octaplas) is licensed and available in the UK. FFP must be thawed using a technique that avoids risk of bacterial contamination. Plastic packs containing any of these plasma products are brittle in the frozen state and must be handled with care.

Content and functional activity of von Willebrand factor in apheresis plasma

BACKGROUND AND OBJECTIVES

Von Willebrand Factor (VWF) is a complex high-molecular-weight (HMW) plasma glycoprotein playing a critical role in primary and secondary haemostasis. Owing to its multimeric structure and sensitivity to proteolysis, VWF can be used as a marker of the impact of collection procedures on the characteristics of plasma for transfusion and for fractionation. We studied VWF content, functional activity and HMW multimers in plasmas collected by five different automated apheresis collection procedures.

MATERIALS AND METHODS

Five series of 30 plasma units were obtained from volunteer donors at two collection sites using Haemonetics PCS2 machines with Revision (Rev) F, Rev G, high-separation core (HSC), or filter core (FC) procedures, or Baxter-Fenwall Autopheresis-C (Auto-C). VWF antigen (VWF:Ag), ristocetin cofactor (VWF:RCo) activity and HMW multimers were first determined in 10 randomly selected plasma donations collected with Rev G, HSC, FC and Auto-C procedures. Then, the same analyses and the collagen binding (VWF:CB) activity were determined in the pools of 30 donations from each of the five procedures and compared with two normal plasma pools (NPP1 and NPP2). A reference plasma (RP) was used to calibrate each assay.

RESULTS

There were a greater number of group O individuals in the Rev F, Rev G and FC donors than in the HSC and Auto-C donors. The mean VWF:Ag level was > 100 IU/dl, VWF:RCo activity was > 90 U/dl, the VWF:RCo/Ag ratio was close to 1, and the percentage of 11-15 mers was above 100% of RP in the 10 individual plasma units from Rev G, HSC, FC, and Auto-C and in their respective pools. The mean percentage of multimers > 15 mers, relative to RP, was significantly less in Rev G plasmas (48 +/- 17%; range 32-91%), compared with Auto-C, HSC and FC plasmas (P = 0.0211; 0.0257; and 0.0376, respectively). The VWF:CB activity of the 30-donation pools was 61 and 60 U/dl in Auto C and HSC, 50 U/dl in Rev F and FC, and 43 U/dl in the Rev G pool. The VWF:CB/Ag ratio was 0.54 (Auto-C), 0.49 (HSC), 0.46 (Rev F), 0.45 (FC) and 0.37 (Rev G), compared with 0.81and 0.92 in NPPs. The percentage of VWF multimers of 11-15 mers in apheresis plasma and NPP was normal. VWF multimers > 15 mers ranged from 38 to 64% of that of RP plasma, and was 111 and 112% in NPPs.

CONCLUSIONS

The VWF:Ag, VWF:RCo activity and 11-15 mer VWF multimers were well preserved in all plasma units from each of the five apheresis procedures. The VWF:CB activity and the percentage of multimers > 15 mers in apheresis plasma was less than in normal plasma pools and differed slightly among procedures.