title: Autoimmune characteristics in Japanese children diagnosed with type 1 diabetes before 5 years of age.
abstract: BACKGROUND
  Several studies have shown that the autoimmune features in young children with type 1 diabetes differ from those in older pediatric patients as well as adults. The purpose of the present study was to examine the prevalence of beta-cell autoantibodies, glutamic acid decarboxylase antibodies (GADA), and antibodies to the protein tyrosine phosphatase-related molecule IA-2 (IA-2A), at the time of diagnosis in Japanese children with type 1 diabetes who were younger than 5 years at diagnosis.
  
  
  METHODS
  Subjects consisted of 23 Japanese children (nine boys, 14 girls), 3.1 +/- 1.3 years of age at diagnosis (range, 1.1-4.8 years). The majority had severe metabolic decompensation accompanied by complete absence of beta-cell function at diagnosis. We found 41.7% to have suffered viral infections before disease onset.
  
  
  RESULTS
  The prevalence of antibodies to GAD and IA-2 at diagnosis in these subjects was significantly lower than those in older patients diagnosed after 5 years of age (31.6 % vs 86.3% and 47.1% vs 82.5%, P < 0.0001 and P = 0.0064, respectively). Among 17 patients in whom both antibodies were measured, only two (11.8%) had both GADA and IA-2A, three (17.6%) had GADA alone, six (35.3%) had IA-2A alone, and six (35.3%) had neither GADA nor IA2-A.
  
  
  CONCLUSIONS
  Non-autoimmune mechanisms or age-related differences in autoimmunity could be involved in the pathogenesis of diabetes in young patients.
authors.affiliation: Department of Pediatrics, Nihon University School of Medicine, Tokyo, Japan. turakami@med.nihon-u.ac.jp
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Urakami
authors.forename: Junichi
authors.initials: J
authors.lastname: Suzuki
authors.forename: Ayako
authors.initials: A
authors.lastname: Yoshida
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Saito
authors.forename: Mika
authors.initials: M
authors.lastname: Wada
authors.forename: Shouri
authors.initials: S
authors.lastname: Takahashi
authors.forename: Hideo
authors.initials: H
authors.lastname: Mugishima
mesh_terms: D001323:Autoantibodies / Q000276:immunology*; D002675:Child, Preschool; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology; D006801:Humans; D007223:Infant; D050417:Insulin-Secreting Cells / Q000276:immunology; D008297:Male
chemical_list: D001323:Autoantibodies; C096322:ICA512 autoantibody; D005968:Glutamate Decarboxylase