title: Optimizing JC and BK polyomavirus IgG testing for seroepidemiology and patient counseling.
abstract: BACKGROUND
  Polyomavirus JC (JCPyV) and BK (BKPyV) can cause significant diseases in immunocompromised patients including nephropathy, hemorrhagic cystitis, and leukoencephalopathy. Recently, JCPyV and BKPyV IgG have been explored as risk predictors in multiple sclerosis and transplant patients, but sensitivity, specificity and quantification issues limit current performance.
  
  
  OBJECTIVE
  To improve JCPyV and BKPyV-specific antibody testing.
  
  
  METHODS
  Healthy blood donor sera (N=400) were tested at dilutions 1:100, 1:200, and 1:400 for JCPyV- and BKPyV-specific IgG using VP1 virus-like particle (VLP)-based ELISAs normalized to a laboratory reference serum. Normalized optical density 492nm greater or equal 0.1 in all 3 dilutions was regarded as reactive. Sera with discordant reactivity in at least one dilution were retested after VLP preadsorption.
  
  
  RESULTS
  At dilutions 1:100, 1:200, and 1:400, IgG reactivity was 74%, 60% and 53% for JCPyV, and 93%, 86% and 74% for BKPyV, respectively. At these dilutions, JCPyV-VLP preadsorption identified 56, 4 and 0 false-positives and 0, 4 and 27 false-negatives, respectively. Dilution-dependent sensitivity was 100%, 98%, and 89%, and specificity 65, 98%, and 100%, respectively. For sera diluted 100-, 200-, and 400-fold, BKPyV-VLP preadsorption identified 28, 1 and 0 false-positives, and 0, 0 and 46 false-negatives, and sensitivity was 100%, 100%, 86%, and specificity 50%, 98%, 100%, respectively.
  
  
  CONCLUSIONS
  For seroepidemiology studies, normalized JCPyV and BKPyV IgG ELISA at 1:200 serum dilution provides optimal sensitivity and specificity with the lowest false-positive and false-negative rate. For individual risk assessment, dilutions of 100, 200, and 400 combined with preadsorption for low-reactive sera may be most appropriate.
authors.affiliation: Transplantation & Clinical Virology, Department Biomedicine - Haus Petersplatz, University of Basel, Basel, Switzerland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Kardas
authors.affiliation: Transplantation & Clinical Virology, Department Biomedicine - Haus Petersplatz, University of Basel, Basel, Switzerland.
authors.forename: Céline
authors.initials: C
authors.lastname: Leboeuf
authors.affiliation: Transplantation & Clinical Virology, Department Biomedicine - Haus Petersplatz, University of Basel, Basel, Switzerland; Infection Diagnostics, Department Biomedicine - Haus Petersplatz, University of Basel, Basel, Switzerland; Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland. Electronic address: hans.hirsch@unibas.ch.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Hirsch
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D001739:BK Virus / Q000276:immunology*; D003376:Counseling; D003951:Diagnostic Errors; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D007577:JC Virus / Q000276:immunology*; D027601:Polyomavirus Infections / Q000175:diagnosis* / Q000821:virology; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012698:Serologic Tests / Q000379:methods*; D014412:Tumor Virus Infections / Q000175:diagnosis* / Q000821:virology
chemical_list: D000914:Antibodies, Viral; D007074:Immunoglobulin G
keywords: Antibody; BK virus; Cystitis; ELISA; JC virus; Multiple sclerosis; Natalizumab; Nephropathy; PML; Polyomavirus; Screening; Transplantation