title: Influenza A virus antibodies show no association with pancreatic islet autoantibodies in children genetically predisposed to type 1 diabetes.
abstract: OBJECTIVE
  Viral infections have long been considered potential triggers of beta cell autoimmunity and type 1 diabetes. Recent studies have suggested that influenza A virus might increase the risk of type 1 diabetes. The present study evaluates this risk association in prospectively observed children at the time when islet autoimmunity starts and autoantibodies are first detected.
  
  
  METHODS
  IgG class antibodies to influenza A virus were analysed in 95 case children whose antibody screening test turned permanently positive for two or more islet autoantibodies and from 186 autoantibody-negative and non-diabetic control children who were matched for time of birth, sex, date of sampling and HLA-conferred risk of diabetes in the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) study. Virus antibodies were measured from the first autoantibody-positive sample using an enzyme immunoassay. None of the children had been vaccinated against influenza A.
  
  
  RESULTS
  The prevalence of influenza A virus antibodies did not differ between the case and control children (42% vs 38%; p = 0.392) and the median antibody levels were also comparable in the two groups (3.0 vs 3.8 enzyme immunoassay units). A similar result was obtained when case and control children were compared separately in subgroups according to different sex, age and HLA-DQ genotype. However, girls had higher antibody levels than boys among both case and control children (median antibody levels 9.0 vs 2.3 enzyme immunoassay units; p = 0.01).
  
  
  CONCLUSIONS
  Our results suggest that influenza A infections are not associated with the development of islet autoimmunity in young children with increased genetic susceptibility to type 1 diabetes.
authors.affiliation: School of Medicine, University of Tampere, Biokatu 10, FIN-33520, Tampere, Finland.
authors.forename: Anita
authors.initials: A
authors.lastname: Kondrashova
authors.affiliation: School of Medicine, University of Tampere, Biokatu 10, FIN-33520, Tampere, Finland.
authors.forename: Noora
authors.initials: N
authors.lastname: Nurminen
authors.affiliation: School of Medicine, University of Tampere, Biokatu 10, FIN-33520, Tampere, Finland.
authors.forename: Maarit
authors.initials: M
authors.lastname: Patrikainen
authors.affiliation: School of Health Sciences, University of Tampere, Tampere, Finland.
authors.forename: Heini
authors.initials: H
authors.lastname: Huhtala
authors.affiliation: School of Medicine, University of Tampere, Biokatu 10, FIN-33520, Tampere, Finland.
authors.forename: Jussi
authors.initials: J
authors.lastname: Lehtonen
authors.affiliation: Department of Physiology, University of Turku, Turku, Finland.|Department of Pediatrics, Turku University Hospital, Turku, Finland.
authors.forename: Jorma
authors.initials: J
authors.lastname: Toppari
authors.affiliation: Department of Clinical Microbiology, University of Eastern Finland, Kuopio, Finland.|Immunogenetics Laboratory, University of Turku, Turku, Finland.
authors.forename: Jorma
authors.initials: J
authors.lastname: Ilonen
authors.affiliation: Department of Pediatrics, Turku University Hospital, Turku, Finland.
authors.forename: Olli G
authors.initials: OG
authors.lastname: Simell
authors.affiliation: Department of Pediatrics, University of Oulu, Oulu, Finland.
authors.forename: Riitta
authors.initials: R
authors.lastname: Veijola
authors.affiliation: Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland.|Research Programs Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland.|Folkhälsan Research Center, Helsinki, Finland.|Tampere Center for Child Health Research, Tampere University Hospital, Tampere, Finland.
authors.forename: Mikael
authors.initials: M
authors.lastname: Knip
authors.affiliation: School of Medicine, University of Tampere, Biokatu 10, FIN-33520, Tampere, Finland. Heikki.Hyoty@uta.fi.|Fimlab Laboratories, Pirkanmaa Hospital District, Tampere, Finland. Heikki.Hyoty@uta.fi.
authors.forename: Heikki
authors.initials: H
authors.lastname: Hyöty
mesh_terms: D000293:Adolescent; D000914:Antibodies, Viral / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D015551:Autoimmunity / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000276:immunology*; D007515:Islets of Langerhans / Q000276:immunology*; D008297:Male
chemical_list: D000914:Antibodies, Viral; D001323:Autoantibodies
keywords: Influenza A virus; Type 1 diabetes; Virus antibodies