title: Quencher-enhanced specificity of psoralen-photosensitized virus inactivation in platelet concentrates.
abstract: BACKGROUND
  Treatment with psoralens and UVA (PUVA) has been shown to be efficacious in eliminating the risk of virus transmission by platelet concentrates (PCs). It has previously been demonstrated that, during the inactivation of cell-free vesicular stomatitis virus (VSV) by aminomethyltrimethylpsoralen (AMT) and UVA in PCs, platelet function could be protected either by oxygen removal before irradiation or by inclusion of a type I free radical quencher, such as mannitol.
  
  
  METHODS
  Under previous PUVA treatment conditions for PCs (25 micrograms/mL AMT; 30 min UVA at 7 mW/cm2; 2 mM [2 mmol/L] mannitol), more than 6 log10 of added cell-free VSV was completely inactivated. In the current study, various PUVA conditions are evaluated for efficacy in inactivating other viral forms that could be present in PCs. Maintenance of platelet integrity (i.e., platelet number, solution pH, and aggregation response during initial storage after treatment) and kill of cell-associated VSV are examined.
  
  
  RESULTS
  While cell-free viruses were inactivated efficiently under previous PUVA conditions, cell-associated VSV and the non-lipid-enveloped bacteriophage M13 were not. Effective inactivation of these viruses was achieved by raising the concentration of AMT to 50 micrograms per mL and extending the period of irradiation to 90 minutes (39 J/cm2). However, for maintenance of platelet integrity under these conditions, the prior removal of oxygen or the inclusion of compounds known to quench both type I and type II photoreactants (e.g., flavonoids such as rutin) was required.
  
  
  CONCLUSIONS
  These findings suggest that the viral safety of PCs may be enhanced through treatment with AMT and UVA in the presence of flavonoids, and that flavonoid use may prove beneficial in other systems where oxygen-mediated damage occurs.
authors.affiliation: New York Blood Center, New York.
authors.forename: H
authors.initials: H
authors.lastname: Margolis-Nunno
authors.forename: R
authors.initials: R
authors.lastname: Robinson
authors.forename: E
authors.initials: E
authors.lastname: Ben-Hur
authors.forename: B
authors.initials: B
authors.lastname: Horowitz
mesh_terms: D000998:Antiviral Agents; D017104:Bacteriophage M13 / Q000187:drug effects / Q000528:radiation effects; D001792:Blood Platelets / Q000382:microbiology* / Q000502:physiology; D006801:Humans; D017713:Platelet Transfusion; D014307:Trioxsalen / Q000031:analogs & derivatives* / Q000494:pharmacology; D014466:Ultraviolet Rays; D014721:Vesicular stomatitis Indiana virus / Q000187:drug effects / Q000528:radiation effects; D014777:Virus Diseases / Q000517:prevention & control / Q000635:transmission; D018406:Virus Physiological Phenomena; D014780:Viruses / Q000187:drug effects / Q000528:radiation effects
chemical_list: D000998:Antiviral Agents; C018822:aminomethyltrioxsalen; D014307:Trioxsalen