title: JCV epidemiology in MS (JEMS)--epidemiology of anti-JCV antibody prevalence in multiple sclerosis patients--Portuguese data.
abstract: BACKGROUND
  Progressive multifocal leukoencephalopathy, caused by oligodendrocyte lytic infection by JCVirus, is a growing concern for patients undergoing immune modulatory therapies for treatment of autoimmune diseases, such as multiple sclerosis (MS). The objective of JEMS was to describe the prevalence of anti-JCV antibodies in MS patients and to assess the various factors associated to it.
  
  
  METHODS
  Serum samples were collected and tested for anti-JCV antibody using the STRATIFY JCV™ assay in 131 Portuguese MS patients. Factors potentially associated with prevalence were also evaluated, as well as the effect of established risk factors.
  
  
  RESULTS
  In the population of 131 Portuguese patients included in the JEMS, the overall anti-JCV antibody prevalence was 69.5% (95% CI, 61.6-77.4). The anti-JCV antibody prevalence did not seem to be influenced by demographic characteristics, although results demonstrate a non-significant trend for increased prevalence with age. Disease characteristics, treatment duration, treatment history, prior immunosuppressive therapy use and natalizumab exposure duration did not seem to be associated with anti-JCV prevalence.
  
  
  CONCLUSIONS
  The results of Portuguese MS patients participating in the JEMS study present some differences when compared with the global population and literature results. An overall prevalence higher than expected raises awareness for data confirmation with greater sample size studies.
authors.affiliation: Centro Hospitalar do Porto, Hospital de Santo António, Portugal. Electronic address: anaadmsilva@gmail.com.
authors.forename: Ana Martins
authors.initials: AM
authors.lastname: da Silva
authors.affiliation: Centro Hospitalar do Porto, Hospital de Santo António, Portugal.
authors.forename: Maria Ernestina
authors.initials: ME
authors.lastname: Santos
mesh_terms: D000293:Adolescent; D000328:Adult; D000888:Antibodies, Anti-Idiotypic / Q000378:metabolism*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007577:JC Virus / Q000276:immunology*; D007968:Leukoencephalopathy, Progressive Multifocal / Q000453:epidemiology*; D008297:Male; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000276:immunology / Q000821:virology; D011174:Portugal / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000888:Antibodies, Anti-Idiotypic
keywords: Anti-JCV antibody; JCV; Multiple sclerosis; Prevalence; Progressive multifocal leukoencephalopathy; Stratify JCV