title: Prion reduction of red blood cells: impact on component quality.
abstract: BACKGROUND
  A filter has been developed (P-Capt, MacoPharma) to remove infectious prions from red blood cells (RBCs). We sought to assess 1) its operational use, 2) the quality of filtered components, and 3) whether filtration resulted in any significant changes to blood group antigens.
  
  
  METHODS
  A total of 272 leukoreduced RBC units, including units processed using "top-and-top" (TAT) and "bottom-and-top" (BAT) methods, were prion reduced using the P-Capt filter. All RBCs were assessed using standard in vitro tests of RBC quality. Changes to blood group antigen expression were also investigated, including the exposure of cryptantigens and the ability of filtered RBCs to be crossmatched.
  
  
  RESULTS
  Ninety-nine percent of TAT units and 58% of BAT units had a hemoglobin (Hb) content of more than 40 g. Hemolysis increased immediately after filtration, but units remained within UK specification throughout storage. Prion reduction resulted in the loss of 7 to 8 g of Hb and reductions in hematocrit of 6% to 9% due to the filter containing 40 mL of saline, adenine, glucose, and mannitol. Other RBC quality data, including extracellular potassium, 2,3-diphosphoglycerate, and adenosine triphosphate were similar to historical control data. There was no evidence of any immunologic changes of clinical relevance to the RBC membrane after filtration.
  
  
  CONCLUSIONS
  Prion filtration does not appear to have a detrimental effect on basic in vitro measures of RBC quality or on blood group antigens as assessed by in vitro methods. However, prion filtration using the P-Capt filter results in loss of Hb.
authors: Components Development Laboratory, NHS Blood and Transplant, Essex, UK. michael.wiltshire@nhsbt.nhs.uk
authors: Michael
authors: M
authors: Wiltshire
authors: Stephen
authors: S
authors: Thomas
authors: Janet
authors: J
authors: Scott
authors: Vicky
authors: V
authors: Hicks
authors: Martin
authors: M
authors: Haines
authors: Phil
authors: P
authors: Cookson
authors: Margaret
authors: M
authors: Garwood
authors: Rebecca
authors: R
authors: Cardigan
mesh_terms: D019794:2,3-Diphosphoglycerate / Q000097:blood; D000255:Adenosine Triphosphate / Q000097:blood; D001793:Blood Preservation; D007562:Creutzfeldt-Jakob Syndrome / Q000517:prevention & control*; D004912:Erythrocytes / Q000737:chemistry* / Q000276:immunology; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D047589:Leukocyte Reduction Procedures / Q000379:methods*; D011328:Prions / Q000097:blood / Q000302:isolation & purification*
chemical_list: D006454:Hemoglobins; D011328:Prions; D019794:2,3-Diphosphoglycerate; D000255:Adenosine Triphosphate