title: Vitamin D, HLA-DRB1 and Epstein-Barr virus antibody levels in a prospective cohort of multiple sclerosis patients.
abstract: Our objective was to study the association between serum levels of anti Epstein-Barr virus nuclear antigen 1 (EBNA-1) antibody and 25-hydroxyvitamin D (25(OH)D) in a prospective cohort of patients with relapsing-remitting multiple sclerosis.
  
  
  
  The study comprised 90 patients with relapsing-remitting multiple sclerosis, all participants in a randomized clinical trial of ω-3 fatty acids (the OFAMS study). Repeated, paired measurements of serum 25(OH)D and serum EBNA-1 immunoglobulin G (IgG) levels were obtained at baseline and every 6 months for 24 months. The association between serum EBNA-1 IgG and serum 25(OH)D levels was analysed using generalized linear models for hierarchical data.
  
  
  
  There was a significant variation in EBNA-1 IgG antibody level between sampling months (Fdf 11 = 1.8, P = 0.043, one-way anova). There was a negative association between EBNA-1 IgG and 25(OH)D [B = -0.230, 95% confidence interval (CI) (-0.440, -0.023), P = 0.030] and a positive association between EBNA-1 IgG and HLA-DRB1*15 positive status [B = 94.7, 95% CI (2.423, 186.9), P = 0.044]. The association between 25(OH)D and EBNA-1 IgG remained significant after adjusting for the patient's age, gender, HLA-DRB1*15, retinol levels and interferon β-1a treatment.
  
  
  
  Our study demonstrates monthly differences in EBNA-1 IgG levels and an association between EBNA-1 IgG, 25(OH)D levels and HLA-DRB1*15. These results indicate that EBNA-1 IgG serum levels are affected by genetic and environmental factors that also modulate multiple sclerosis risk.
authors.affiliation: Department of Neurology, Norwegian Multiple Sclerosis Competence Centre, Haukeland University Hospital, Bergen, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Wergeland
authors.affiliation: Department of Clinical Medicine, KG Jebsen MS Research Centre, University of Bergen, Bergen, Norway.|Institute of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
authors.forename: K-M
authors.initials: KM
authors.lastname: Myhr
authors.affiliation: Department of Neurology, Innlandet Hospital Trust, Lillehammer, Norway.
authors.forename: K I
authors.initials: KI
authors.lastname: Løken-Amsrud
authors.affiliation: Multiple Sclerosis Centre Hakadal, Hakadal, Norway.
authors.forename: A G
authors.initials: AG
authors.lastname: Beiske
authors.affiliation: Clinic of Laboratory Medicine, St Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.|Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: K S
authors.initials: KS
authors.lastname: Bjerve
authors.affiliation: Department of Neurology, St Olavs Hospital, Trondheim University Hospital, Trondheim, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Hovdal
authors.affiliation: Department of Neurology, Molde Hospital, Molde, Norway.|Unit for Applied Clinical Research, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: R
authors.initials: R
authors.lastname: Midgard
authors.affiliation: Department of Laboratory Medicine, Haukeland University Hospital, Bergen, Norway.
authors.forename: S S
authors.initials: SS
authors.lastname: Kvistad
authors.affiliation: Department of Neurology, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Holmøy
authors.affiliation: Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.
authors.forename: T
authors.initials: T
authors.lastname: Riise
authors.affiliation: Department of Neurology, Norwegian Multiple Sclerosis Competence Centre, Haukeland University Hospital, Bergen, Norway.|Institute of Clinical Medicine, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
authors.forename: Ø
authors.initials: Ø
authors.lastname: Torkildsen
mesh_terms: D000293:Adolescent; D000328:Adult; D019309:Epstein-Barr Virus Nuclear Antigens / Q000097:blood*; D005260:Female; D059811:HLA-DRB1 Chains / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000097:blood*; D011446:Prospective Studies; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D055815:Young Adult
chemical_list: D019309:Epstein-Barr Virus Nuclear Antigens; D059811:HLA-DRB1 Chains; D014807:Vitamin D; C104450:25-hydroxyvitamin D; C417029:EBV-encoded nuclear antigen 1
keywords: Epstein-Barr virus; multiple sclerosis; prospective cohort study; vitamin D