Cesium cessation? An advantage of pathogen reduction treatments

Risks associated with red blood cell transfusions: potential benefits from application of pathogen inactivation

BACKGROUND

Red blood cell (RBC) transfusion risks could be reduced if a robust technology for pathogen inactivation of RBC (PI-RBCs) were to be approved.

MATERIALS AND METHODS

Estimates of per-unit and per-patient aggregate infectious risks for conventional RBCs were calculated; the latter used patient diagnosis as a determinant of estimated lifetime exposure to RBC units. Existing in vitro data for the two technologies under development for producing PI-RBCs and the status of current clinical trials are reviewed.

RESULTS

Minimum and maximum per-unit risk were calculated as 0.0003% (1 in 323,000) and 0.12% (1 in 831), respectively. The minimum estimate is for known lower-risk pathogens while the maximal estimate also includes an emerging infectious agent (EIA) and endemic area Babesia risk. Minimum and maximum per-patient lifetime risks by diagnosis grouping were estimated as 1.5 and 3.3%, respectively, for stem cell transplantation (which includes additional risk for cytomegalovirus transmission); 1.2 and 3.7%, respectively, for myelodysplastic syndrome; and 0.2 and 44%, respectively, for hemoglobinopathy.

DISCUSSION

There is potential for PI technologies to reduce infectious RBC risk and to provide additional benefits (e.g., prevention of transfusion-associated graft-versus-host disease and possible reduction of alloimmunization) due to white blood cell inactivation. PI-RBCs should be viewed in the context of having a fully PI-treated blood supply, enabling a blood safety paradigm shift from reactive to proactive. Providing insurance against new EIAs. Further, when approved, the use of PI for all components may catalyze operational changes in blood donor screening, laboratory testing, and component manufacturing.

Cost implications of implementation of pathogen-inactivated platelets

BACKGROUND

Pathogen inactivation (PI) is a new approach to blood safety that may introduce additional costs. This study identifies costs that could be eliminated, thereby mitigating the financial impact.

STUDY DESIGN AND METHODS

Cost information was obtained from five institutions on tests and procedures (e.g., irradiation) currently performed, that could be eliminated. The impact of increased platelet (PLT) availability due to fewer testing losses, earlier entry into inventory, and fewer outdates with a 7-day shelf life were also estimated. Additional estimates include costs associated with managing 1) special requests and 2) test results, 3) quality control and proficiency testing, 4) equipment acquisition and maintenance, 5) replacement of units lost to positive tests, 6) seasonal or geographic testing, and 7) health department interactions.

RESULTS

All costs are mean values per apheresis PLT unit in USD ($/unit). The estimated test costs that could be eliminated are $71.76/unit and a decrease in transfusion reactions corresponds to $2.70/unit. Avoiding new tests (e.g., Babesia and dengue) amounts to $41.80/unit. Elimination of irradiation saves $8.50/unit, while decreased outdating with 7-day storage can be amortized to $16.89/unit. Total potential costs saved with PI is $141.65/unit. Costs are influenced by a variety of factors specific to institutions such as testing practices and the location in which such costs are incurred and careful analysis should be performed. Additional benefits, not quantified, include retention of some currently deferred donors and scheduling flexibility due to 7-day storage.

CONCLUSIONS

While PI implementation will result in additional costs, there are also potential offsetting cost reductions, especially after 7-day storage licensing.

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

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

Treatment of buffy coat platelets in platelet additive solution with the mirasol(®) pathogen reduction technology system

BACKGROUND

The Mirasol pathogen reduction technology (PRT) system uses riboflavin and ultraviolet light and is currently approved and used in Europe for the treatment of platelets and plasma. Mirasol treatment is intended to reduce the infectious pathogen load and to inactivate leukocytes in blood products. Our objective was to evaluate buffy coat platelet concentrates (BCPCs) prepared with platelet additive solution (PAS) and treated with the Mirasol system and to examine the effects on platelet cell quality during storage.

METHODS

26 BCPCs were prepared and split, creating 13 paired control and test units. The test units were treated with the Mirasol system and the platelet quality was assessed in all units over 7 days of storage.

RESULTS

All products met the incoming specifications for Mirasol treatment, and the pH of all Mirasol-treated BCPCs in PAS met the requirements of the Council of Europe guidelines throughout storage. Analysis of lactate production and glucose consumption rates, CD62p expression and cytokines indicates enhanced cellular metabolism in treated platelets, but the levels were within previously published ranges.

CONCLUSION

While Mirasol-treated BCPCs in PAS had increased metabolism and activation compared to controls, the results indicate that these units can be stored for 7 days with acceptable cell quality.

Treatment of whole blood with riboflavin plus ultraviolet light, an alternative to gamma irradiation in the prevention of transfusion-associated graft-versus-host disease?

BACKGROUND

Exposure of blood products to gamma irradiation is currently the standard of care in the prevention of transfusion-associated graft-versus-host disease (TA-GVHD). Regulatory, technical, and clinical challenges associated with the use of gamma irradiators are driving efforts to develop alternatives. Pathogen reduction methods were initially developed to reduce the risk of microbial transmission by blood components. Through modifications of nucleic acids, these technologies interfere with the replication of both pathogens and white blood cells (WBCs). To date, systems for pathogen and WBC inactivation of products containing red blood cells are less well established than those for platelets and plasma.

STUDY DESIGN AND METHODS

In this study, the in vitro and in vivo function of WBCs present in whole blood after exposure to riboflavin plus ultraviolet light (Rb-UV) was examined and compared to responses of WBCs obtained from untreated or gamma-irradiated blood by measuring proliferation, cytokine production, activation, and antigen presentation and xenogeneic (X-)GVHD responses in an in vivo mouse model.

RESULTS

In vitro studies demonstrated that treatment of whole blood with Rb-UV was as effective as gamma irradiation in preventing WBC proliferation, but was more effective in preventing antigen presentation, cytokine production, and T-cell activation. Consistent with in vitro findings, treatment with Rb-UV was as effective as gamma irradiation in preventing X-GVHD, a mouse model for TA-GVHD.

CONCLUSION

The ability to effectively inactivate WBCs in fresh whole blood using Rb-UV, prior to separation into components, provides the transfusion medicine community with a potential alternative to gamma irradiation.

Pyridoxine-related metabolite concentrations in normal and Down syndrome amniotic fluid

INTRODUCTION

Some studies of children with Down syndrome have found mild abnormalities in the metabolism of pyridoxine (vitamin B(6)); therefore the present question is whether such abnormalities might also be present in the amniotic fluid of fetuses with Down syndrome.

MATERIALS AND METHODS

Archived specimens of amniotic fluid were obtained from chromosomally normal and from fetuses with Down syndrome. Gas chromatography/mass spectrometry quantitized B-related metabolites, including oxalate, xanthurenate, kynurenine and 4-pyridoxic acid.

RESULTS

Oxalate, a marker of pyridoxine deficiency, was elevated in the amniotic fluid of fetuses with Down syndrome. This result was statistically significant. The other marker results were not statistically significant.

CONCLUSION

A marker of pyridoxine deficiency, oxalate is elevated in the amniotic fluid of fetuses with Down syndrome. These results in amniotic fluid are consistent with previous studies done in the urine of young children.