Longitudinal stability of JCV antibody index in Natalizumab treated people with multiple sclerosis

• Published in: Multiple sclerosis and related disorders 2022-12, Vol.68, p.104251-104251, Article 104251
• Main Authors: Gaughan, M., Gilligan, M., Patterson, I., McGurgan, I., Yap, S.M., Tubridy, N., McGuigan, C.
• Format: Article
• Language: English
• Subjects: Antibodies, Viral; Humans; Immunologic Factors - therapeutic use; JC Virus; JCV; Leukoencephalopathy, Progressive Multifocal; Multiple sclerosis; Multiple Sclerosis - drug therapy; Natalizumab; Natalizumab - therapeutic use; PML; Retrospective Studies
• ISSN: 2211-0348; 2211-0356
• DOI: 10.1016/j.msard.2022.104251

•There is a trend towards increasing index over time in those with a baseline positive JCV index value.•In patients with baseline negative JCV, the majority remained negative through follow-up.•Rates of seroconversion approximated 5.8% per year, with a median time to seroconversion of 103 months. The aim of this study was to evaluate the evolution of JCV index over time in Natalizumab treated people with multiple sclerosis. We retrospectively reviewed antibody index values from pwMS who were treated with Natalizumab for greater than six months and had at least two antibody results available between 2011 and 2019. Survival analysis was performed on those who were JCV index value negative at baseline to evaluate time to seroconversion. In pwMS who had index values available at 48 and/or 96 months post Natalizumab initiation, t-tests were performed to evaluate change in index over time. 1144 JCV antibody index results were available for 132 pwMS. Median time to seroconversion based on survival analysis was 103 months. Annualised seroconversion rate was 5.8%. Initial antibody index and rate of seroconversion did not differ with regards to age or gender. Antibody index increased significantly over time on treatment for the cohort as a whole, initial antibody index (0.27) to final antibody testing (0.86), t(131)=6.45, p