title: Development of a bifunctional filter for prion protein and leukoreduction of red blood cell components.
abstract: BACKGROUND
  Leukofiltration of blood components is currently implemented worldwide as a precautionary measure against white blood cell-associated adverse effects and the potential transmission of variant Creutzfeldt-Jakob disease (vCJD). A newly developed bifunctional filter (Sepacell Prima, Asahi Kasei Medical) was assessed for prion removal, leukoreduction (LR), and whether the filter significantly affected red blood cells (RBCs).
  
  
  METHODS
  Sepacell Prima's postfiltration effects on RBCs, including hemolysis, complement activation, and RBC chemistry, were compared with those of a conventional LR filter (Sepacell Pure RC). Prion removal was measured by Western blot after spiking RBCs with microsomal fractions derived from scrapie-infected hamster brain homogenate. Serially diluted exogenous prion solutions (0.05 mL), with or without filtration, were injected intracerebrally into Golden Syrian hamsters.
  
  
  RESULTS
  LR efficiency of 4.44 log with the Sepacell Prima was comparable to 4.11 log with the conventional LR filter. There were no significant differences between the two filters in hemoglobin loss, hemolysis, complement activation, and RBC biomarkers. In vitro reduction of exogenously spiked prions by the filter exceeded 3 log. The titer, 6.63 (log ID50 /mL), of prefiltration infectivity of healthy hamsters was reduced to 2.52 (log ID50 /mL) after filtration. The reduction factor was calculated as 4.20 (log ID50 ).
  
  
  CONCLUSIONS
  With confirmed removal efficacy for exogenous prion protein, this new bifunctional prion and LR filter should reduce the residual risk of vCJD transmission through blood transfusion without adding complexity to component processing.
authors.affiliation: Sepacell Development Planning Department, Asahi Kasei Medical, Oita, Japan.
authors.forename: Tomo
authors.initials: T
authors.lastname: Yokomizo
authors.forename: Takako
authors.initials: T
authors.lastname: Kai
authors.forename: Morikazu
authors.initials: M
authors.lastname: Miura
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ohto
mesh_terms: D000818:Animals; D017848:Blood-Borne Pathogens; D007562:Creutzfeldt-Jakob Syndrome / Q000097:blood / Q000517:prevention & control / Q000635:transmission; D006224:Cricetinae; D004912:Erythrocytes; D005260:Female; D006440:Hemofiltration / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008297:Male; D008647:Mesocricetus; D011328:Prions; D012608:Scrapie / Q000097:blood / Q000517:prevention & control / Q000635:transmission
chemical_list: D011328:Prions