Inter- and Intralaboratory Comparison of JC Polyomavirus Antibody Testing Using Two Different Virus-Like Particle-Based Assays

Abstract

e 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.

Progressive multifocal leukoencephalopathy and hematologic malignancies: a single cancer center retrospective review

“…1,15,16 However, with new ultrasensitive PCR techniques, the sensitivity is .95%, and the specificity is .97%. 1,3 In this series, there were 4 falsenegative CSF tests, but clinical suspicion led to a confirmatory brain biopsy, which must be pursued in suspicious cases. In our series, there were also 2 false-positive results.…”

“…19,20 These biomarkers have not been validated in other conditions, and the significance and utility of JCV testing in patients with hematologic malignancies have not been investigated but warrant study, especially in those receiving chronic immunosuppressive treatment. 3,9,18 Prevention is valuable, because the condition is almost universally fatal. 1 In a review of 57 HIV-negative lymphoma patients treated with rituximab who developed PML, there was a 90% fatality rate within a median survival of 2.0 months.…”

“…By early adulthood, approximately half of the general population is JCV positive, and seroprevalence continues to increase with age. [1][2][3] Normally, cellular immunity keeps the virus quiescent where it is harbored (in the urinary tract, bone marrow, lymphoid tissue, and possibly the central nervous system). 2,4,5 However, patients with abnormalities in cell-mediated immunity are vulnerable to viral reactivation, and replication occurs in glial cells (predominantly oligodendrocytes) and neurons of the cerebrum and granular cell layer of the cerebellum.…”

Characterization of Immunodominant BK Polyomavirus 9mer Epitope T Cell Responses

“…BKPyV IgG serology was performed using BKPyV VP1‐derived virus‐like particles, as described previously 4, 57, 58.…”

Comparison of Two Commercial Tick-Borne Encephalitis Virus IgG Enzyme-Linked Immunosorbent Assays

“…During the past 5 years, samples underwent three cycles of freezing and thawing. The stability of the antibody activities was independently confirmed by ELISA in another study (11). All sera were stored at Ϫ20°C; aliquots of the samples were thawed and stored at 4°C during the testing period and were refrozen afterwards.…”