Filtration of methylene blue-photooxidized plasma: influence on coagulation and cellular contamination

Viral safety of APOSECTM: a novel peripheral blood mononuclear cell derived-biological for regenerative medicine

BACKGROUND

Viral reduction and inactivation of cell-derived biologicals is paramount for patients' safety and so viral reduction needs to be demonstrated to regulatory bodies in order to obtain marketing authorisation. Allogeneic human blood-derived biological medicinal products require special attention. APOSEC^TM, the secretome harvested from selected human blood cells, is a new biological with promising regenerative capabilities. We evaluated the effectiveness of inactivation of model viruses by methylene blue/light treatment, lyophilisation, and gamma irradiation during the manufacturing process of APOSEC^TM.

MATERIALS AND METHODS

Samples of intermediates of APOSEC^TM were acquired during the manufacturing process and spiked with bovine viral diarrhoea virus (BVDV), human immunodeficiency virus type 1 (HIV-1), pseudorabies virus (PRV), hepatitis A virus (HAV), and porcine parvovirus (PPV). Viral titres were assessed with suitable cell lines.

RESULTS

Methylene blue-assisted viral reduction is mainly effective against enveloped viruses: the minimum log₁₀ reduction factors for BVDV, HIV-1, and PRV were ≥6.42, ≥6.88, and ≥6.18, respectively, with no observed residual infectivity. Viral titres of both HAV and PPV were not significantly reduced, indicating minor inactivation of non-enveloped viruses. Lyophilisation had minor effects on the viability of several enveloped model viruses. Gamma irradiation contributes to the viral safety by reduction of enveloped viruses (BVDV: ≥2.42; HIV-1: 4.53; PRV: ≥4.61) and to some degree of non-enveloped viruses as seen for HAV with a minimum log10 reduction factor of 2.92. No significant reduction could be measured for the non-enveloped virus PPV (2.60).

DISCUSSION

Three manufacturing steps of APOSEC^TM were evaluated under Good Laboratory Practice conditions for their efficacy at reducing and inactivating potentially present viruses. It could be demonstrated that all three steps contribute to the viral safety of APOSEC^TM.

Clearance of serum solutes by hemofiltration in dogs with severe heat stroke

Background

We have previously reported that hemofiltration (HF) may be an effective additional means of treating heat stroke when rapid cooling is not effective.

Methods

Dogs were assigned to a heat stroke (control) or heat stroke + hemofiltration (HF) group (n = 8 each group). After heat stroke induction, dogs in the HF group received HF for 3 h. Serum concentrations of interleukin (IL)-10, tumor necrosis factor (TNF)-α, IL-6, blood urea nitrogen (BUN) and creatinine were measured at baseline and 1, 2, and 3 h after heat stroke. Clearance rates of solutes were determined 1, 2, and 3 h after the start of HF.

Results

Serum concentrations of all solutes tended to increase with time after heat stroke in the control group, but decreased (BUN, creatinine) or remained relatively unchanged (TNF-α, IL-6, IL-10) with time in the HF group. Concentrations of all solutes were significantly lower in the HF group compared with the control group at 2 and 3 h (P < 0.05). Clearance rates for small molecular weight solutes were high, while those for larger molecular weight solutes were low.

Conclusion

HF prevents heat stroke-induced increases in serum cytokine concentrations and is effective for clearing small molecular weight solutes from serum, but less effective for clearing larger molecular weight solutes, including TNF-α, IL-6, and IL-10.

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.

[Evolution of techniques for preparation of labile blood products (LBP): pathogen inactivation in LBP]

The techniques for inactivation of pathogens in labile blood products (LBP) would appear to be the new strategy which will permit us to increase transfusion safety in the face of the risks of transmission of pathogenic agents by LBP. Various methods are in the course of development or already validated and used in France. The latter only apply however to plasma or platelet concentrates. The mechanisms of action and the efficacy of inactivation and attenuation of pathogenic agents vary with the different techniques. Each of these constitutes a preparative procedure composed of unit steps which have to be fully mastered in order to ensure the quality and transfusion efficacy of the treated product.

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.

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.

Recessively inherited coagulation disorders

Deficiencies of coagulation factors other than factor VIII and factor IX that cause bleeding disorders are inherited as autosomal recessive traits and are rare, with prevalences in the general population varying between 1 in 500 000 and 1 in 2 million for the homozygous forms. As a consequence of the rarity of these deficiencies, the type and severity of bleeding symptoms, the underlying molecular defects, and the actual management of bleeding episodes are not as well established as for hemophilia A and B. We investigated more than 1000 patients with recessively inherited coagulation disorders from Italy and Iran, a country with a high rate of recessive diseases due to the custom of consanguineous marriages. Based upon this experience, this article reviews the genetic basis, prevalent clinical manifestations, and management of these disorders. The steps and actions necessary to improve the condition of these often neglected patients are outlined.

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

BACKGROUND

T: he effects of using fresh or frozen-thawed plasma, WBC reduction of plasma before freezing, and the use of two different methylene blue (MB) removal filters on the quality of MB-treated plasma were compared.

STUDY DESIGN AND METHODS

In a paired study (n = 11/arm) plasma was frozen within 8 hours of collection, thawed, MB photoinactivated, and then filtered using one of two MB removal filters. Fresh plasma (n = 16) and plasma WBC reduced before freezing (n = 19) were MB inactivated.

RESULTS

Freeze-thawing resulted in loss of activity of FXII and VWF of 0.06 and 0.04 units per mL, respectively, but no significant loss of activity of factors II through XI or fibrinogen. Further loss of activity occurred after MB treatment: FII (0.07 IU/mL), FV (0.11 U/mL), FVII (0.08 IU/mL), FVIII (0.28 IU/mL), F IX (0.12 IU/mL), FX (0.16 IU/mL), FXI (0.28 U/mL), FXII (0.15 U/mL), VWF antigen (0.05 IU/mL), VWF activity (0.06 U/mL), and fibrinogen (0.79 g/L). Losses due to this step were significantly (5-10%) lower in fresh plasma compared to frozen-thawed plasma. Neither MB removal filter resulted in significant loss of activity of any factor studied.

CONCLUSION

MB removal, by either of the available filters, has little impact on the coagulation factor content of plasma, but freezing of plasma before MB treatment results in a small additional loss.

Nucleic acid technology screening of Australian blood donors for hepatitis C and human immunodeficiency virus-1 RNA: comparison of two high-throughput testing strategies

BACKGROUND AND OBJECTIVES

The aim of this study was to compare the performance of two high-throughput strategies for hepatitis C virus (HCV) and human immunodeficiency virus-1 (HIV-1) RNA nucleic acid technology (NAT) screening in a volunteer blood-donor population.

MATERIALS AND METHODS

The semiautomated Chiron Procleix HIV-1/HCV transcription mediated amplification (TMA) assay was used to screen 1 439 765 donations in two different testing configurations. Three sites (termed PDT sites) performed a mixture of individual donation (ID) and minipool (MP) testing, where 1 113 288 donations were screened as pools of 24 and an additional 32 003 donations were screened in ID format. A further two sites (termed SDT sites) screened 294 474 donations exclusively in ID format.

RESULTS

A significantly higher proportion of initial NAT reactives that failed to react on follow-up testing [termed non-repeatably reactive (NRR)] was observed for ID testing at SDT sites than at PDT sites (0.082 vs. 0.047%: P < 0.01). Within the PDT sites, however, there was no significant difference between the NRR rate for MP or ID samples (0.037 vs. 0.047%; not significant). There was a significant difference in failed run rates between PDT and SDT sites (P < 0.01), with PDT sites having a higher run failure rate owing to non-amplification of the internal control. The PDT sites also had a significantly higher overall invalid sample rate. However, the invalid sample rate, specifically caused by known equipment failure, was significantly higher in the SDT sites, possibly attributable to greater usage (P < 0.0001). Four HCV NAT-positive/antibody-negative samples were identified in the course of the study.

CONCLUSIONS

The comparison of the performance of PDT with SDT sites identified only minor differences that did not adversely impact on the timely release of blood products. Although both ID and MP strategies showed excellent specificity, irrespective of site configuration, the significantly increased NRR rate, observed exclusively for ID testing performed at SDT sites, indicates a potential for contamination that may limit the number of samples that can optimally be processed using ID testing. The performance data for ID testing in particular should serve as a useful benchmark for evaluating candidate NAT systems that are fully automated.

Manufacture and composition of fresh frozen plasma and virus-inactivated therapeutic plasma preparations: correlation between composition and therapeutic efficacy

The clinical efficacy of the therapeutic plasma used in the treatment of congenital and acquired severe coagulopathy depends on the potency of clotting factor and inhibitor activities. The composition of plasma strongly depends on the conditions under which it is produced. A low citrate anticoagulant-to-blood ratio, short intervals between donation and plasma separation and rapid freezing markedly improve the preservation of unstable coagulation factors. The influence of different leukocyte reduction filters on plasma quality still requires clarification. Recent trials on long-term storage conditions suggest that keeping plasma at -30 degrees C or colder over a period of 24-36 months prevents substantial decrease in clotting factor activities including factor VIII (FVIII). Three types of therapeutic plasma are currently available. Quarantine-stored fresh frozen plasma (FFP) contains physiological activities of therapeutically relevant plasma proteins, but carries a risk of transmitting blood-borne viruses that cannot be detected by human immunodeficiency virus (HIV) and hepatitis B and C screening. In contrast, solvent/detergent-treated plasma (SDP) and methylene blue/light-treated plasma (MBP) is virtually free of HIV and hepatitis C virus (HCV) subtypes. Virus inactivation procedures can have the consequence of reducing several clotting factors and inhibitors in SDP and MBP to varying degrees. However, pooling of plasma units before solvent/detergent (SD) treatment results in well-standardized protein levels of SDP. At least five prospective trials and four observational studies covering different clinical settings suggest that SDP and FFP do not substantially differ in their clinical efficacy or in their tolerance. By way of contrast, there is a lack of data about the clinical efficacy and tolerance of MBP compared to FFP.

Transfusing methylene blue-photoinactivated plasma instead of FFP is associated with an increased demand for plasma and cryoprecipitate

BACKGROUND

Photodynamic virus inactivation of plasma with methylene blue significantly decreases the recovery of fibrinogen and coagulation factors V and VIII. Because an adequate supply of fibrinogen is essential for the therapeutic efficacy of transfused plasma in many clinical settings, it was plausible that transfusing photoinactivated plasma (PIP) instead of FFP would result in an increased demand for plasma and cryoprecipitate.

STUDY DESIGN AND METHODS

The study involved a retrospective analysis of the use of plasma at a university hospital (Barcelona, Spain) over three 1-year periods: one before the implementation of PIP therapy and two after. Blood components transfused to plasma recipients were listed by broad diagnostic categories based on the Diagnosis-Related Group classification.

RESULTS

During the period under study, 2,967 patients were given plasma in this hospital. They received 27,434 units of plasma, 1,660 of cryoprecipitate, 10,079 of platelets, and 24,607 of packed RBCs. Patients undergoing surgical procedures accounted for 74 percent of all transfused plasma. In 71 percent of patient admissions, packed RBCs were transfused in addition to plasma. Diagnostic categories with the greatest requirement for plasma were cardiac valve surgery, liver transplant, wounds and traumatic injuries, and bowel surgery. The use of PIP was associated with a 56-percent increase in the aggregated demand for plasma, whereas the transfusion of non-virus-inactivated cryoprecipitate increased twofold the first year and threefold the second year. The growth in the use of plasma took place in all the diagnostic categories. In those categories that include patients with liver disease, a partial substitution of PIP for cryoprecipitate was observed during the second year after PIP therapy implementation.

CONCLUSION

The use of PIP was associated with a marked increase in the demand for plasma and cryoprecipitate, which probably was due to the low hemostatic quality of the new component. It is possible that such an increase overrode the potential health benefits derived from transfusing virus-inactivated plasma.