In vitro assessment of red‐cell concentrates in SAG‐M filtered through the MacoPharma™ P‐CAPT prion‐reduction filter

Abstract

This study investigated whether filtration of leucodepleted red cells in SAG-M through the P-CAPT filter in order to prevent the potential risk of vCJD infection associated with prion transmission through transfusion has any deleterious effect on red-cell quality. Bottom-and-top SAG-M leucodepleted red-cell concentrates (24 units) were prion-reduction filtered on the day following collection, with half of the units undergoing irradiation on day 14. A control group (12 units) was not prion filtered. Units were sampled at 7-day intervals up to day 35 and tested using standard measures of red-cell quality as well as prothrombin content (to examine prion filter efficacy). Haemoglobin loss per unit was approximately 9 g and in some cases levels were below standard specification (40 g). Haemolysis increased significantly after filtration [0.01 (0.00-0.05) vs. 0.23 (0.07-0.52, p<0.001)]. Prothrombin levels were reduced 41.6-fold compared to leucodepleted red-cell units. Product specifications were within or close to routine acceptable levels. Owing to the reduction in haemoglobin levels below those specified, it may be preferable to reduce haemoglobin specification levels and transfuse more prion-filtered units rather than transfuse potentially unsafe blood product. The risk of transfusing more units with less haemoglobin should be offset against the risk of transfusing unfiltered blood.

Transfusion of prion‐filtered red cells does not increase the rate of alloimmunization or transfusion reactions in patients: results of the UK trial of prion‐filtered versus standard red cells in surgical patients (PRISM A)

“…In line with a number of smaller studies (Murphy et al, 2009;Cancelas et al, 2011) we found that transfusion of PF-RCC did not result in increased immunogenicity or other significant complications in patients. In addition, we demonstrated that alloimmunization rates in surgical patients, irrespective of study arm, were similar to previous reports (Redman et al, 1996).…”

“…P-Capt filtered red blood cell concentrates (PF-RCC) behaved normally in laboratory assays and had a normal antigenic profile (Murphy et al, 2009), and a study in 20 patients showed that exposure to 1-2 PF-RCC units did not generate any attributable adverse events (Cahill et al, 2010).…”

Infusion of P‐Capt prion‐filtered red blood cell products demonstrate acceptable in vivo viability and no evidence of neoantigen formation

“…The resin also demonstrated the ability to remove endogenous infectivity from hamster leukoreduced RBCs to below the limit of detection of the bioassay used to determine the infectivity titer 11 . RBC storage variables after leukoreduced RBCs were filtered with the P‐Capt prion filter and then stored with either plasma‐CPD or SAGM to outdate have been evaluated 16‐18 . All of the final variables (hemoglobin [Hb] g/unit, hematocrit [Hct], residual WBCs, total volume) as well as end of shelf life product variables (hemolysis, adenosine 5′‐triphosphate [ATP], 2,3‐diphosphoglycerate acid [2,3‐DPG], potassium, and pH) were within the UK and Council of Europe Guidelines 19,20 .…”

Cost‐effectiveness of prion filtration of red blood cells to reduce the risk of transfusion‐transmitted variant Creutzfeldt‐Jakob disease in the Republic of Ireland

“…All of these cases occurred in the United Kingdom before the introduction of universal leukoreduction of RBCs. The high incidence of vCJD in Ireland has raised concerns that there may be a significant risk of secondary transmission through infected blood products 6 …”

“…The use of such filters would complement existing measures adopted to contain the risk of transmission. Although prion‐removing filters may alter the composition of RBCs that are passed through them, the resulting RBCs are considered safe for transfusion 6,10 . The aim of this study was to evaluate the cost‐effectiveness of implementing a policy of prion filtration of RBCs in the Republic of Ireland.…”