An assay to quantify species-specific anti-JC virus antibody levels in MS patients

作者：Warnke Clemens; Pawlita Michael; Dehmel Thomas; Posevitz Fejfar Anita; Hartung Hans Peter; Wiendl Heinz; Kieseier Bernd C; Adams Ortwin^*

来源：Multiple Sclerosis, 2013, 19(9): 1137-1144.

DOI：10.1177/1352458513475489

• Multiple sclerosis
• Tysabri
• JC virus
• progressive multifocal leukoencephalopathy
• BK virus

Background: The StratifyJCV (R) test is a qualitative assay to classify MS patients as anti-JC virus (JCV) antibody positive or negative. Quantification of anti-JCV antibody levels in serum and cerebrospinal fluid (CSF) of multiple sclerosis (MS) patients might add to the progressive multifocal leukoencephalopathy (PML) risk assessment. %26lt;br%26gt;Objective: The objective of this study is to test sera of patients in a quantitative anti-JCV antibody assay, and to compare the results with preexisting data from the StratifyJCV (R) test. %26lt;br%26gt;Methods: Sera of a total of 175 MS patients and matched non-MS-controls were tested for anti-JCV antibodies using glutathione S-transferase-tagged-VP1 as antigen. Antibody reactivity was quantified in arbitrary units using human immunoglobulin as standard. %26lt;br%26gt;Results: The comparison of our assay with StratifyJCV (R) showed good inter-assay agreement (kappa 0.6), and strong correlation for antibody reactivity (r(2) = 0.94). Discordant samples had low-reactive positivity, and a higher proportion (13% vs. 4%) tested positive in the StratifyJCV (R) test only. %26lt;br%26gt;Conclusions: The method presented is a tool for the reliable quantification of anti-JCV antibodies, which demonstrates good agreement with results from StratifyJCV (R). In contrast to StratifyJCV (R), we pre-adsorbed all of the sera with BK virus (BKV) VP1 protein to reduce cross-reactivity. This step may account for a higher species-specificity of our assay. As such, our assay might be a promising additional tool for PML risk assessment.

• 出版日期2013-8