title: Infusion of P-Capt prion-filtered red blood cell products demonstrate acceptable in vivo viability and no evidence of neoantigen formation.
abstract: BACKGROUND
  Transmission of variant Creutzfeldt-Jacob disease (vCJD) is a major concern in blood transfusion. The P-Capt filter has been shown to remove around 4 log ID(50) prion infectivity from prion-spiked human red blood cells (RBCs).
  
  
  METHODS
  Two independent, single-center, randomized, open-label studies were designed to analyze the safety of P-Capt-filtered RBCs. RBCs prepared from leukoreduced whole blood from 43 eligible subjects were randomly assigned to P-Capt filtration and/or storage in plasma or SAGM and stored for 28 or 42 days. Stored RBCs were analyzed for in vivo 24-hour recovery, hemolysis, metabolic variables, blood group antigen expression, neoantigen formation, and safety after autologous infusion.
  
  
  RESULTS
  Mean P-Capt filtration times for leukoreduced RBCs were 41 (SAGM) to 51 (plasma) minutes. Thirteen of 14 subjects receiving P-Capt-filtered RBCs had 24-hour RBC recoveries of 75% or more after 42-day storage, with a mean hemolysis of less than 0.6%. No loss of RBC antigen expression or formation of neoantigens was observed. In both studies, RBCs had white blood cell counts of less than 1 × 10(6)/unit after leukofiltration. P-Capt prion filtration provided an additional greater than 0.8 log leukoreduction. No serious or unexpected adverse events were observed after infusion of P-Capt-filtered full-volume RBC units.
  
  
  CONCLUSIONS
  P-Capt-filtered, stored RBCs demonstrated acceptable viability and no detectable neoantigen expression, immunogenic responses. or safety issues after infusion of a complete unit. The additional filtration time and modest reduction in RBC content are within acceptable levels for implementation in countries with transfusion transmission of vCJD.
authors.affiliation: Hoxworth Blood Center, University of Cincinnati, Cincinnati, Ohio 45267-0055, USA. jose.cancelas@uc.edu
authors.forename: Jose A
authors.initials: JA
authors.lastname: Cancelas
authors.forename: Neeta
authors.initials: N
authors.lastname: Rugg
authors.forename: P Gayle
authors.initials: PG
authors.lastname: Pratt
authors.forename: D Nicole
authors.initials: DN
authors.lastname: Worsham
authors.forename: Joan C
authors.initials: JC
authors.lastname: Pehta
authors.forename: Kate
authors.initials: K
authors.lastname: Banks
authors.forename: Robertson D
authors.initials: RD
authors.lastname: Davenport
authors.forename: W John
authors.initials: WJ
authors.lastname: Judd
mesh_terms: D000328:Adult; D001774:Blood Chemical Analysis; D001793:Blood Preservation / Q000379:methods; D058731:Blood Safety / Q000295:instrumentation / Q000379:methods*; D001804:Blood Transfusion, Autologous / Q000379:methods; D007562:Creutzfeldt-Jakob Syndrome / Q000517:prevention & control*; D017707:Erythrocyte Transfusion / Q000009:adverse effects / Q000379:methods*; D004912:Erythrocytes / Q000276:immunology*; D005374:Filtration; D006801:Humans; D047589:Leukocyte Reduction Procedures; D008875:Middle Aged; D011328:Prions / Q000097:blood*; D013997:Time Factors
chemical_list: D011328:Prions