title: Clinical evaluation of a radioimmunoprecipitation assay for IA-2 antibody and comparison of GAD antibody in type 1 diabetes mellitus.
abstract: We evaluated a insulinoma-associated protein (IA-2) antibody assay kit using 125I-labelled recombinant IA-2. IA-2 antibodies were present in patients with early-onset type 1 diabetes mellitus (DM) at frequencies of 74%, 67%, 57%, and 50% for respective periods <1 year, 1 < or =years<2, 2< or =years<3, and 3< or =years<4 after onset. IA-2 antibody frequency was low throughout the DM course as compared with glutamic acid decarboxylase (GAD) antibody frequency. No one had IA-2 antibody, but 29% still had positive GAD antibody titers after 11 years. Of the patients with 0<years<7 duration, 42% had IA-2 Ab+/GAD Ab+, 9% IA-2 Ab+/GAD Ab-, and 24% IA-2 Ab-/GAD Ab+. Prevalence of IA-2 and GAD antibody in 1243 patients with type 2 DM were 1.5% and 3.1%, respectively, and 1.1% had both. This new IA-2 antibody kit is easy to use and provides a specific, sensitive method for making routine assays. Furthermore, the combined analysis of GAD antibody provides high detection of type 1 DM.
authors.affiliation: Clinical Research Center, Utano National Hospital, Narutaki, Kyoto, Japan. m_ohta@utano.hosp.jp
authors.forename: M
authors.initials: M
authors.lastname: Ohta
authors.forename: K
authors.initials: K
authors.lastname: Ohta
authors.forename: H
authors.initials: H
authors.lastname: Obayashi
authors.forename: N
authors.initials: N
authors.lastname: Nakamura
authors.forename: H
authors.initials: H
authors.lastname: Shigeta
authors.forename: K
authors.initials: K
authors.lastname: Nakano
authors.forename: G
authors.initials: G
authors.lastname: Hasegawa
authors.forename: M
authors.initials: M
authors.lastname: Fukui
authors.forename: Y
authors.initials: Y
authors.lastname: Kitagawa
authors.forename: M
authors.initials: M
authors.lastname: Nishimura
authors.forename: N
authors.initials: N
authors.lastname: Itoh
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D001323:Autoantibodies / Q000097:blood*; D016022:Case-Control Studies; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D003924:Diabetes Mellitus, Type 2 / Q000276:immunology; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D008875:Middle Aged; D015531:Radioimmunoprecipitation Assay / Q000379:methods* / Q000706:statistics & numerical data; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D001323:Autoantibodies; C096322:ICA512 autoantibody; D005968:Glutamate Decarboxylase