title: Inactivation of parvovirus B19 in human platelet concentrates by treatment with amotosalen and ultraviolet A illumination.
abstract: BACKGROUND
  The human erythrovirus B19 (B19) is a small (18- to 26-nm) nonenveloped virus with a single-stranded DNA genome of 5.6 kb. B19 is clinically significant and is also generally resistant to pathogen inactivation methods. Photochemical treatment (PCT) with amotosalen and ultraviolet A (UVA) inactivates viruses, bacteria, and protozoa in platelets (PLTs) and plasma prepared for transfusion. In this study, the capacity of PCT to inactivate B19 in human PLT concentrates was evaluated.
  
  
  METHODS
  B19 inactivation was measured by a novel enzyme-linked immunosorbent spot (ELISPOT) erythroid progenitor cell infectivity assay and by inhibition of long-range (up to 4.3 kb) polymerase chain reaction (PCR), under conditions where the whole coding region of the viral genome was amplified. B19-infected plasma was used to test whether incubation of amotosalen with virus before PCT enhanced inactivation compared to immediate PCT.
  
  
  RESULTS
  Inactivation of up to 5.8 log of B19 as measured by the infectivity assay, or up to 6 logs as measured by PCR inhibition can be achieved under non-limiting conditions. Inactivation efficacy was found to increase with incubation prior to UVA illumination. Without incubation prior to illumination 2.1 +0.4 log was inactivated as determined by infectivity assay. When measured by PCR inhibition, inactivation varied inversely with amplicon size. When primers that spanned the entire coding region of the B19 genome were used, maximum inhibition of PCR amplification was demonstrated.
  
  
  CONCLUSIONS
  Under defined conditions, PCT with amotosalen combined with UVA light can be used to inactivate B19, a clinically significant virus that can be transmitted through blood transfusion, and heretofore has been demonstrated to be refractory to inactivation.
authors.affiliation: Cerus Corporation, Concord, California 94520, USA. lynette_sawyer@cerus.com
authors.forename: Lynette
authors.initials: L
authors.lastname: Sawyer
authors.forename: Deborah
authors.initials: D
authors.lastname: Hanson
authors.forename: Grace
authors.initials: G
authors.lastname: Castro
authors.forename: William
authors.initials: W
authors.lastname: Luckett
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Dubensky
authors.forename: Adonis
authors.initials: A
authors.lastname: Stassinopoulos
mesh_terms: D001792:Blood Platelets / Q000821:virology*; D004279:DNA, Viral / Q000032:analysis / Q000235:genetics; D016731:Erythema Infectiosum / Q000517:prevention & control; D015672:Erythroid Precursor Cells / Q000821:virology; D011564:Furocoumarins / Q000494:pharmacology; D016679:Genome, Viral / Q000235:genetics; D006801:Humans; D007118:Immunoassay; D016732:Parvovirus B19, Human / Q000235:genetics; D010777:Photochemistry; D014466:Ultraviolet Rays; D038301:Virus Inactivation / Q000187:drug effects* / Q000528:radiation effects*
chemical_list: D004279:DNA, Viral; D011564:Furocoumarins; C118577:amotosalen