title: Inter- and intralaboratory comparison of JC polyomavirus antibody testing using two different virus-like particle-based assays.
abstract: JC polyomavirus (JCPyV) can cause progressive multifocal leukoencephalopathy (PML), a debilitating, often fatal brain disease in immunocompromised patients. JCPyV-seropositive multiple sclerosis (MS) patients treated with natalizumab have a 2- to 10-fold increased risk of developing PML. Therefore, JCPyV serology has been recommended for PML risk stratification. However, different antibody tests may not be equivalent. To study intra- and interlaboratory variability, sera from 398 healthy blood donors were compared in 4 independent enzyme-linked immunoassay (ELISA) measurements generating >1,592 data points. Three data sets (Basel1, Basel2, and Basel3) used the same basic protocol but different JCPyV virus-like particle (VLP) preparations and introduced normalization to a reference serum. The data sets were also compared with an independent method using biotinylated VLPs (Helsinki1). VLP preadsorption reducing ≥35% activity was used to identify seropositive sera. The results indicated that Basel1, Basel2, Basel3, and Helsinki1 were similar regarding overall data distribution (P = 0.79) and seroprevalence (58.0, 54.5, 54.8, and 53.5%, respectively; P = 0.95). However, intra-assay intralaboratory comparison yielded 3.7% to 12% discordant results, most of which were close to the cutoff (0.080 < optical density [OD] < 0.250) according to Bland-Altman analysis. Introduction of normalization improved overall performance and reduced discordance. The interlaboratory interassay comparison between Basel3 and Helsinki1 revealed only 15 discordant results, 14 (93%) of which were close to the cutoff. Preadsorption identified specificities of 99.44% and 97.78% and sensitivities of 99.54% and 95.87% for Basel3 and Helsinki1, respectively. Thus, normalization to a preferably WHO-approved reference serum, duplicate testing, and preadsorption for samples around the cutoff may be necessary for reliable JCPyV serology and PML risk stratification.
authors.affiliation: Transplantation and Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Basel, Switzerland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Kardas
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland.
authors.forename: Mohammadreza
authors.initials: M
authors.lastname: Sadeghi
authors.affiliation: Transplantation and Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Basel, Switzerland.
authors.forename: Fabian H
authors.initials: FH
authors.lastname: Weissbach
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland.
authors.forename: Tingting
authors.initials: T
authors.lastname: Chen
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland Department of Virology and Immunology, Helsinki University Central Hospital Laboratory Services, Helsinki, Finland.
authors.forename: Lea
authors.initials: L
authors.lastname: Hedman
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland Department of Virology and Immunology, Helsinki University Central Hospital Laboratory Services, Helsinki, Finland.
authors.forename: Eeva
authors.initials: E
authors.lastname: Auvinen
authors.affiliation: Department of Virology, Haartman Institute, University of Helsinki, Helsinki, Finland Department of Virology and Immunology, Helsinki University Central Hospital Laboratory Services, Helsinki, Finland.
authors.forename: Klaus
authors.initials: K
authors.lastname: Hedman
authors.affiliation: Transplantation and Clinical Virology, Department Biomedicine (Haus Petersplatz), University of Basel, Basel, Switzerland Infectious Diseases and Hospital Epidemiology, University Hospital Basel, Basel, Switzerland Division of Infection Diagnostics, Department Biomedicine (Haus Petersplatz), University of Basel, Switzerland hans.hirsch@unibas.ch.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Hirsch
mesh_terms: D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D007577:JC Virus / Q000276:immunology*; D007968:Leukoencephalopathy, Progressive Multifocal / Q000175:diagnosis*; D027601:Polyomavirus Infections / Q000175:diagnosis*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D022701:Virosomes
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D022701:Virosomes