title: Testing UK blood donors for exposure to human parvovirus 4 using a time-resolved fluorescence immunoassay to screen sera and Western blot to confirm reactive samples.
abstract: BACKGROUND
  Human parvovirus 4 (ParV4), a newly described member of the family Parvoviridae, like B19V, has been found in pooled plasma preparations. The extent, and significance, of ParV4 exposure in UK blood donors remain to be determined and reliable detection of ParV4 immunoglobulin (Ig)G, using validated methods, is needed.
  
  
  METHODS
  With ParV4 virus-like particles a ParV4 IgG time-resolved fluorescence immunoassay (TRFIA) was developed. There is no gold standard or reference assay for measuring ParV4 IgG and the utility of the TRFIA was first examined using a panel of sera from people who inject drugs (PWIDS)--a high-prevalence population for ParV4 infection. Western blotting was used to confirm the specificity of TRFIA-reactive sera. Two cohorts of UK blood donor sera comprising 452 sera collected in 1999 and 156 sera collected in 2009 were tested for ParV4 IgG. Additional testing for B19V IgG, hepatitis C virus antibodies (anti-HCV), and ParV4 DNA was also undertaken.
  
  
  RESULTS
  The rate of ParV4 IgG seroprevalence in PWIDS was 20.7% and ParV4 IgG was positively associated with the presence of anti-HCV with 68.4% ParV4 IgG-positive sera testing anti-HCV-positive versus 17.1% ParV4 IgG-negative sera. Overall seropositivity for ParV4 IgG, in 608 UK blood donors was 4.76%. The ParV4 IgG seropositivity for sera collected in 1999 was 5.08%, compared to 3.84% for sera collected in 2009. No ParV4 IgG-positive blood donor sera had detectable ParV4 DNA.
  
  
  CONCLUSIONS
  ParV4 IgG has been found in UK blood donors and this finding needs further investigation.
authors.affiliation: Immunisation and Diagnosis Unit, Virus Reference Department, Public Health England, London, UK.
authors.forename: Peter A C
authors.initials: PA
authors.lastname: Maple
authors.forename: Stuart
authors.initials: S
authors.lastname: Beard
authors.forename: Ruth P
authors.initials: RP
authors.lastname: Parry
authors.forename: Kevin E
authors.initials: KE
authors.lastname: Brown
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001782:Blood Donors; D015153:Blotting, Western; D015200:Fluoroimmunoassay; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D010322:Parvoviridae Infections / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D017992:Parvovirus / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods; D016036:Seroepidemiologic Studies; D061987:Sf9 Cells; D006113:United Kingdom / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral