title: Enterovirus RNA in longitudinal blood samples and risk of islet autoimmunity in children with a high genetic risk of type 1 diabetes: the MIDIA study.
abstract: OBJECTIVE
  Only a few longitudinal molecular studies of enterovirus and islet autoimmunity have been reported, and positive results seem to be limited to Finland. We aimed to investigate an association between enterovirus RNA in blood and islet autoimmunity in the MIDIA study from Norway, a country which largely shares environmental and economic features with Finland.
  
  
  METHODS
  We analysed serial blood samples collected at ages 3, 6, and 9 months and then annually from 45 children who developed confirmed positivity for at least two autoantibodies (against insulin, GAD65 and IA-2) and 92 matched controls, all from a cohort of children with a single high-risk HLA-DQ-DR genotype. Enterovirus was tested in RNA extracted from frozen blood cell pellets, using real-time RT-PCR with stringent performance control.
  
  
  RESULTS
  Out of 807 blood samples, 72 (8.9%) were positive for enterovirus. There was no association between enterovirus RNA and islet autoimmunity in samples obtained strictly before (7.6% cases, 10.0% controls, OR 0.75 [95% CI 0.36, 1.57]), or strictly after the first detection of islet autoantibodies (10.5% case, 5.8% controls, OR 2.00 [95% CI 0.64, 6.27]). However, there was a tendency towards a higher frequency of enterovirus detection in the first islet autoantibody-positive sample (15.8%) compared with the corresponding time point in matched controls (3.2%, OR 8.7 [95% CI 0.97, 77]). Neither of these results was changed by adjusting for potential confounders, restricting to various time intervals or employing various definitions of enterovirus positivity.
  
  
  CONCLUSIONS
  Positivity for enterovirus RNA in blood did not predict the later induction of islet autoantibodies, but enterovirus tended to be detected more often at the islet autoantibody seroconversion stage.
authors.affiliation: Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, V Uvalu 84, 15006, Prague 5, Czech Republic, Ondrej.Cinek@Lfmotol.cuni.cz.
authors.forename: Ondrej
authors.initials: O
authors.lastname: Cinek
authors.forename: Lars C
authors.initials: LC
authors.lastname: Stene
authors.forename: Lenka
authors.initials: L
authors.lastname: Kramna
authors.forename: German
authors.initials: G
authors.lastname: Tapia
authors.forename: Sami
authors.initials: S
authors.lastname: Oikarinen
authors.forename: Elisabet
authors.initials: E
authors.lastname: Witsø
authors.forename: Trond
authors.initials: T
authors.lastname: Rasmussen
authors.forename: Peter A
authors.initials: PA
authors.lastname: Torjesen
authors.forename: Heikki
authors.initials: H
authors.lastname: Hyöty
authors.forename: Kjersti S
authors.initials: KS
authors.lastname: Rønningen
mesh_terms: D001323:Autoantibodies / Q000097:blood; D015551:Autoimmunity / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology* / Q000821:virology*; D004770:Enterovirus / Q000235:genetics* / Q000302:isolation & purification; D005260:Female; D005802:Genes, MHC Class II / Q000235:genetics; D006683:HLA-DQ Antigens / Q000235:genetics; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D012367:RNA, Viral / Q000097:blood*
chemical_list: D001323:Autoantibodies; D006683:HLA-DQ Antigens; D012367:RNA, Viral