title: Epstein Barr virus (EBV) antibodies in the diagnosis of NPC--comparison between IFA and two commercial ELISA kits.
abstract: BACKGROUND
  Antibodies to Epstein Barr Virus (EBV) antigens have been used for the diagnosis of nasopharyngeal carcinoma (NPC). While immunofluorescence assays (IFA) of IgA antiviral capsid and early antigens have been the mainstay of this diagnosis, enzyme immunoassays (ELISA) of various EBV antigens are now available. However in almost all of these assays, the sensitivities and specificities have been calculated using blood donors and normal hospital staff as controls, who may not be the most appropriate controls. We wanted to evaluate the usefulness of IFA and ELISA of various EBV antigens in a clinical setting to distinguish between patients with NPC and those suspected of NPC but being biopsy negative.
  
  
  METHODS
  Between January 1987 and June 1988, 322 consecutive patients suspected of NPC and who had a post-nasal biopsy were studied. Blood was taken for EBV tests before diagnosis. Tests included IFA and ELISA IgA anti-VCA and anti-EA and ELISA IgA and IgG anti-ribonucleotide reductase, a cloned EA antigen.
  
  
  RESULTS
  IFA IgA anti-VCA together with IFA IgA anti-EA both at a cut-off of 1:10 gave the best discrimination between patients with NPC and those suspected of NPC but were biopsy negative.
  
  
  CONCLUSIONS
  The ELISA IgG anti-ribonucleotide reductase test is convenient to perform and looks very promising. An ELISA using a cocktail of cloned EA peptides may be even better.
authors.affiliation: WHO Immunology Collaborating Centre, Faculty of Medicine, National University of Singapore, Singapore.
authors.forename: S H
authors.initials: SH
authors.lastname: Chan
authors.forename: M Y
authors.initials: MY
authors.lastname: Soo
authors.forename: Y Y
authors.initials: YY
authors.lastname: Gan
authors.forename: A
authors.initials: A
authors.lastname: Fones-Tan
authors.forename: P S
authors.initials: PS
authors.lastname: Sim
authors.forename: A
authors.initials: A
authors.lastname: Kaur
authors.forename: C T
authors.initials: CT
authors.lastname: Chew
mesh_terms: D000914:Antibodies, Viral / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D005455:Fluorescent Antibody Technique / Q000592:standards; D004854:Herpesvirus 4, Human / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis; D009303:Nasopharyngeal Neoplasms / Q000175:diagnosis* / Q000276:immunology / Q000821:virology; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D000914:Antibodies, Viral; D014408:Biomarkers, Tumor; D007070:Immunoglobulin A