The cost-effectiveness of pathogen reduction technology as assessed using a multiple risk reduction model

A reappraisal of plasma, prothrombin complex concentrates, and recombinant factor VIIa in patient blood management

Plasma therapy and plasma products such as prothrombin complex concentrates (PCCs), and recombinant activated factor VII (rFVIIa) are used in the setting of massive or refractory hemorrhage. Their roles have evolved because of newly emerging options, variable availability, and heterogeneity in guidelines. These factors can be attributable to lack of evidence-based support for a defined role for plasma therapy, variability in coagulation factor content among PCCs, and uncertainty regarding safety and efficacy of rFVIIa in these settings. This review summarizes these issues and provides insight regarding use of these options in management of refractory or massive bleeding.

Pathogen Reduction Technology Treatment of Platelets, Plasma and Whole Blood Using Riboflavin and UV Light

Bacterial contamination and emerging infections combined with increased international travel pose a great risk to the safety of the blood supply. Tests to detect the presence of infection in a donor have a 'window period' during which infections cannot be detected but the donor may be infectious. Agents and their transmission routes need to be recognized before specific tests can be developed. Pathogen reduction of blood components represents a means to address these concerns and is a proactive approach for the prevention of transfusion-transmitted diseases. The expectation of a pathogen reduction system is that it achieves high enough levels of pathogen reduction to reduce or prevent the likelihood of disease transmission while preserving adequate cell and protein quality. In addition the system needs to be non-toxic, non-mutagenic and should be simple to use. The Mirasol® Pathogen Reduction Technology (PRT) System for Platelets and Plasma uses riboflavin (vitamin B2) plus UV light to induce damage in nucleic acid-containing agents. The system has been shown to be effective against clinically relevant pathogens and inactivates leukocytes without significantly compromising the efficacy of the product or resulting in product loss. Riboflavin is a naturally occurring vitamin with a well-known and well-characterized safety profile. The same methodology is currently under development for the treatment of whole blood, making pathogen reduction of all blood products using one system achievable. This review gives an overview of the Mirasol PRT System, summarizing the mechanism of action, toxicology profile, pathogen reduction performance and clinical efficacy of the process.

In vivo viability of stored red blood cells derived from riboflavin plus ultraviolet light-treated whole blood

BACKGROUND

A novel system using ultraviolet (UV) light and riboflavin (Mirasol System, CaridianBCT Biotechnologies) to fragment nucleic acids has been developed to treat whole blood (WB), aiming at the reduction of potential pathogen load and white blood cell inactivation. We evaluated stored red blood cell (RBC) metabolic status and viability, in vitro and in vivo, of riboflavin/UV light-treated WB (IMPROVE study).

STUDY DESIGN AND METHODS

The study compared recovery and survival of RBCs obtained from nonleukoreduced WB treated using three different UV light energies (22, 33, or 44 J/mL(RBC)). After treatment, WB from 12 subjects was separated into components and tested at the beginning and end of component storage. After 42 days of storage, an aliquot of RBCs was radiolabeled and autologously reinfused into subjects for analysis of 24-hour recovery and survival of RBCs.

RESULTS

Eleven subjects completed the in vivo study. No device-related adverse events were observed. By Day 42 of storage, a significant change in the concentrations of sodium and potassium was observed. Five subjects had a 24-hour RBC recovery of 75% or more with no significant differences among the energy groups. RBC t(1/2) was 24 ± 9 days for the combined three groups. Significant correlations between 24-hour RBC recovery and survival, hemolysis, adenosine triphosphate (ATP), and CO(2) levels were observed.

CONCLUSIONS

This study shows that key RBC quality variables, hemolysis, and ATP concentration may be predictive of their 24-hour recovery and t(1/2) survival. These variables will now be used to assess modifications to the system including storage duration, storage temperature, and appropriate energy dose for treatment.

White blood cell inactivation after treatment with riboflavin and ultraviolet light

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

Influence of irradiation on in vitro red-blood-cell (RBC) storage variables of leucoreduced RBCs in additive solution PAGGS-M

BACKGROUND

The effect of gamma irradiation on leucoreduced red-blood-cells (RBCs) stored in an additive solution (AS) containing phosphate, adenine, glucose, guanosine, saline and mannitol (PAGGS-M) has not yet been studied, and there are different recommendations about storage time of leucoreduced RBCs after irradiation.

STUDY DESIGN AND METHODS

We studied 63 leucoreduced RBC units. All RBCs were stored in AS PAGGS-M and leucoreduced on the collection day. Twenty-one components were irradiated on Day +14 with 30 Gy and 22 served as non-irradiated controls. Samples were drawn and analysed from these 43 units on Day +7, +14, +21, +28, +35, +42 and +49 from the collection day. From 20 units, no samples were taken earlier than on Day +49. Of these, 10 components had been irradiated on Day +14 with 30 Gy and 10 served as non-irradiated controls.

RESULTS

Gamma irradiation induced an enhanced in vitro haemolysis rate in the irradiated components. One of the irradiated units showed a haemolysis rate over the recommended limit of 0·8% on Day +42 and four on Day +49. The leakage of potassium ions from irradiated RBCs started to increase faster than that of unirradiated RBCs from the day of irradiation. Lactate dehydrogenase levels increased faster in irradiated units 3 weeks after irradiation. We showed that taking samples weekly does not affect the final result.

CONCLUSIONS

Our findings show that the European recommendations should not be changed in regard to the limitation of the storageability after irradiation of leucoreduced RBCs. The damage after irradiation and storage cannot be prevented by using the high-quality AS PAGGS-M.