title: Sourcing of the WHO human papillomavirus type 18 international standards for HPV antibody levels.
abstract: BACKGROUND
  HPV serology is important for studies of vaccine immunogenicity, but can not be performed in a comparable manner without international standardisation.
  
  
  OBJECTIVE
  To find suitable candidate sera from naturally infected persons for use as International Standards (IS) for antibodies to high-risk HPVs, with priority for HPV-18.
  
  
  METHODS
  946 healthy Thai women (median age 44, range 18-83) and 61 cervical cancer patients were screened using an HPV pseudovirion-Luminex assay to detect antibodies to genital (HPV-6,-11,-16,-18,-31,-33,-45,-52,-58,-68) and non-genital HPV types (HPV-5,-15,-32,-38 and -76). Suitable candidate sera should ideally be mono-specific (have reactivity against only one genital HPV) and have high antibody levels that are stable over time.
  
  
  RESULTS
  Seroprevalences of HPV-16,-31,-52 and -58 were at least twice as high among cancer patients compared to healthy individuals. Thirteen healthy women who met the IS inclusion criteria in initial testing also consented to blood-bag donations. Donations from 2 women with high HPV-18 Ab titers were pooled to the HPV-18 candidate IS, later established as the WHO official IS for HPV antibodies. Sera that could potentially be used as candidate IS for other oncogenic HPVs have also been identified.
  
  
  CONCLUSIONS
  In the Thai population, seroepidemiology implicated HPV types HPV-16,-31,-52 and -58 as particularly associated with cervical cancer. A well characterized cohort study has allowed sourcing of materials for an IS for HPV-18 antibodies and could conceivably be used for IS for other HPV types as well.
authors.affiliation: Department of Laboratory Medicine, Karolinska Institiute, Stockholm, Sweden.
authors.forename: Helena
authors.initials: H
authors.lastname: Faust
authors.affiliation: Department of Laboratory Medicine, Karolinska Institiute, Stockholm, Sweden.
authors.forename: Carina
authors.initials: C
authors.lastname: Eklund
authors.affiliation: National Cancer Institute, Bangkok, Thailand.
authors.forename: Sukhon
authors.initials: S
authors.lastname: Sukvirach
authors.affiliation: National Cancer Institute, Bangkok, Thailand.
authors.forename: Jarunya
authors.initials: J
authors.lastname: Ngamkham
authors.affiliation: Department of Laboratory Medicine, Karolinska Institiute, Stockholm, Sweden. Electronic address: Joakim.dillner@ki.se.
authors.forename: Joakim
authors.initials: J
authors.lastname: Dillner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood*; D015331:Cohort Studies; D005260:Female; D052161:Human papillomavirus 18 / Q000276:immunology*; D006801:Humans; D007118:Immunoassay / Q000592:standards*; D008875:Middle Aged; D030361:Papillomavirus Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology*; D012015:Reference Standards; D016036:Seroepidemiologic Studies; D013785:Thailand / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral
keywords: Cervical cancer; Human papillomavirus (HPV); International standard serum; Luminex; Serology; Thailand