Anti-JC virus (JCV) antibody prevalence in the JCV Epidemiology in MS (JEMS) trial

Background and purposeProgressive multifocal leukoencephalopathy (PML) is caused by reactivation of JC virus (JCV) infection due to combined host and viral factors. Anti-JCV antibodies provide a means to assess JCV exposure and stratify PML risk. The reported seroprevalence of anti-JCV antibodies varies from 39% to 91% depending on assay methodology and population studied. A two-step anti-JCV antibody assay (STRATIFY JCV; Focus Diagnostics, Cypress, CA, USA) detected anti-JCV antibodies in approximately 55% of multiple sclerosis (MS) patients. This study describes the prevalence of anti-JCV antibodies in a large, multinational MS population. MethodsThis cross-sectional epidemiology study was designed to enroll a minimum of 2000 patients with an MS diagnosis of any type, irrespective of treatment, from Europe, Canada and Australia. Anti-JCV antibody prevalence was determined by STRATIFY JCV; the effects of demographic and disease characteristics were evaluated. ResultsA total of 7724 patients from 10 countries participated in the study. Overall anti-JCV antibody prevalence was 57.1% (95% confidence interval 56.0%-58.2%). Seroprevalence was significantly associated with increasing age, gender and country of current residence (P<0.0001). No significant differences in anti-JCV antibody prevalence were associated with MS disease characteristics, including duration and type of MS and number and duration of MS therapies. ConclusionsOverall seroprevalence of anti-JCV antibodies in MS patients from Europe, Canada and Australia was consistent with previous studies using the STRATIFY JCV assay. Anti-JCV prevalence differed significantly by age, gender and country, but no geographical pattern was evident. Disease and treatment type were not associated with differences in anti-JCV antibody status.