title: Cytomegalovirus seropositivity is negatively associated with multiple sclerosis.
abstract: BACKGROUND
  Epidemiological data suggest a role for common viruses in the pathogenesis of multiple sclerosis (MS), and recent data showed a negative association of past cytomegalovirus (CMV) infection on pediatric MS risk.
  
  
  OBJECTIVE
  Our aim was to analyze the association of CMV infection with MS risk in an adult case-control material. A meta-analysis was performed to validate our findings.
  
  
  METHODS
  Epidemiological Investigation in MS (EIMS) is a case-control study with incident cases and population-based controls. Anti-CMV antibody titers were measured with ELISA, and HLA-A and DRB1 genotyping was performed with SSP-PCR, in 658 MS cases, who all fulfilled the McDonald criteria for MS, and 786 controls.
  
  
  RESULTS
  CMV seropositivity was associated with a decreased MS risk, OR = 0.73 (0.58-0.92 95% CI), p = 0.005, adjusted for index age, gender, smoking, sun exposure, EBNA1 IgG titer and HLA-A*02 and DRB1*15. When we removed all cases and controls younger than 18 years at index, the protective effect was still apparent.
  
  
  CONCLUSIONS
  CMV is negatively associated with adult-onset MS pathology, consistent with results from a study on pediatric MS cases. It remains to be shown whether this negative association is due to a true protective effect of CMV infection on MS risk.
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Karolinska University Hospital Solna, Sweden.
authors.forename: E
authors.initials: E
authors.lastname: Sundqvist
authors.forename: T
authors.initials: T
authors.lastname: Bergström
authors.forename: H
authors.initials: H
authors.lastname: Daialhosein
authors.forename: M
authors.initials: M
authors.lastname: Nyström
authors.forename: P
authors.initials: P
authors.lastname: Sundström
authors.forename: J
authors.initials: J
authors.lastname: Hillert
authors.forename: L
authors.initials: L
authors.lastname: Alfredsson
authors.forename: I
authors.initials: I
authors.lastname: Kockum
authors.forename: T
authors.initials: T
authors.lastname: Olsson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003586:Cytomegalovirus Infections / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000821:virology*; D055815:Young Adult
keywords: Multiple sclerosis; case-control study; cytomegalovirus; environmental factors; viral infections