Dynamics Of The Anti-JC-Virus Antibody Index In An Austrian MS Cohort (P2.253)

OBJECTIVE: To explore longitudinal stability of anti-JC virus antibodies (anti-JCV-Ab) index based results in an Austrian multiple sclerosis (MS) cohort. BACKGROUND: Presence of anti-JCV-Ab is a risk factor for progressive multifocal leukoencephalopathy (PML) in natalizumab (NAZ)-treated MS patients. A recent study showed that an anti-JCV-Ab index above >1.5 (no prior immunosuppressive treatment of patients presupposed) correlated with an increased PML risk. DESIGN/METHODS: Anti-JCV-Ab-status and anti-JCV-Ab-index were determined by Unilabs-Denmark with the second-generation assay (STRATIFY-CV-DxSelect™ Focus Diagnostics/Cypress/California). 53 MS patients with their sera analyzed twice, first time prior to treatment start and a follow-up sample during NAZ were included in this analysis. Our cohort includes one case of PML. Positive anti-JCV-Ab index results were categorized low risk if 1.5. RESULTS: 19(36%) of 53 MS patients were anti-JCV-Ab seropositive and 34(64%) were seronegative before natalizumab therapy was initiated. Of the JCV-Ab seropositive group, 10 patients were categorized low risk ( 1.5). At the follow-up measurement during natalizumab treatment, a dynamic was observed in the development of the anti-JCV-Ab index in 15(28%) patients. Seroconversion from negative to positive was seen in 9 patients including one who directly converted into the high risk group. A switch from the low risk into the high risk group was observed in 6 out of 10 patients(60%) with an initial index 1.5. CONCLUSIONS: Our data indicate dynamic of the anti-JCV-Ab-index between the pretreatment samples and the follow-up samples collected during NAZ treatment. Changes were seen in seropositive as well as in seronegative patients. We conclude that continued measurements are important in all patients to keep track on a possible switch into another risk group. The impact of changes in the risk category of individual patients remains to be elucidated. Study Supported by: none Disclosure: Dr. Wipfler has received personal compensation for activities with Merck Serono, Bayer Pharmaceuticals Corp., Novartis, and Biogen Idec. Dr. Harrer has received personal compensation for activities with Merck Serono. Dr. Pilzhas received personal compensation for activities with Biogen Idec and Merck Serono as an attendee at scientific meetings. Dr. Sellner has received personal compensation for activities with Biogen Idec, Terumo, Tatiopharm, and Merck Serono. Dr. Guger has nothing to disclose. Dr. Ransmayr has received personal compensation for activities with Abbott, Allergan Inc., Biogen Idec, Boehringer Ingelheim Pharmaceuticals Inc., Cephalon, Eisai Inc., GlaxoSmithKline Inc., Lundbeck, Merck Serono, Merz Pharma, Novartis, Sanofi-Aventis Pharmaceuticals Inc. and UCB Pharma. Dr. Ransmayr has received research support from Abbott, BIAL, Biogen Idec, Lundbeck, Novartis, and Sanofi-Aventis Pharmaceuticals Inc. Dr. Trinka has received personal compensation for activities with UCB Pharma, Biogen Idec, Gerot-Lannacher, Bial, and Eisai Inc. Dr. Trinka has received research support from Biogen Idec, Novartis, and Bayer Pharmaceuticals Corp. Dr. Kraus has received personal compensation for activities with Allmirall, Bayer Pharmaceuticals Corp., Biogen Idec, Genzyme Corp., Medtronic Inc., Merck Serono, Novartis, and Sanofi-Avent Pharmaceuticals Inc.