title: Emergence of anti-islet autoantibodies in Japanese patients with type 1 diabetes.
abstract: Circulating anti-islet autoantibodies in sera are used as a predictive marker for type 1 diabetes (T1D). We here report two Japanese patients with autoimmune thyroid disease complicated with T1D in whom the time course of anti-islet autoantibodies were observed before the clinical onset of diabetes. Case 1: A woman who had developed Graves' disease at age 25 was diagnosed with type 2 diabetes at age 31; six months later, insulin therapy was started. At age 36 she was diagnosed with T1D due to glutamic acid decarboxylase 65 autoantibodies (GAD65Ab)-positive status and decreased C-peptide levels. With stored sera we retrospectively followed her anti-islet autoantibodies. GAD65Ab, zinc transporter 8 autoantibodies (ZnT8Ab) and insulin autoantibodies (IAA) were found to be positive at age 25. IAA soon turned negative, but GAD65Ab and ZnT8Ab remained positive with high levels. Insulinoma-associated antigen-2 autoantibodies (IA-2Ab) emerged 2 years before the initiation of insulin therapy. She has T1D-susceptible HLA-DRB1-DQB1 haplotypes, (*)0405- (*)0401/(*)0802-(*)0302. Case 2: A 49-year-old woman with hypothyroidism due to 19 years' history of atrophic thyroiditis noticed marked thirst, polyuria and weight loss. On admission she was diagnosed as T1D due to GAD65Ab-positive findings and poor C-peptide response to i.v. glucagon. Retrospective serology revealed the emergence of GAD65Ab and IAA just after the clinical onset. IA-2Ab and ZnT8Ab never developed. She has T1D-susceptible and -resistant HLADRB1- DQB1 haplotypes, (*)0901-(*)0303/(*)1502-(*)0601. The autoantibody profile and the mode of diabetes onset in the two cases were remarkably different. These cases imply that anti-islet autoantibodies do not always precede the onset of T1D.
authors.affiliation: First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Horie
authors.forename: Eiji
authors.initials: E
authors.lastname: Kawasaki
authors.forename: Aya
authors.initials: A
authors.lastname: Shimomura
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Satoh
authors.forename: Ikuko
authors.initials: I
authors.lastname: Ueki
authors.forename: Hironaga
authors.initials: H
authors.lastname: Kuwahara
authors.forename: Takao
authors.initials: T
authors.lastname: Ando
authors.forename: Norio
authors.initials: N
authors.lastname: Abiru
authors.forename: Toshiro
authors.initials: T
authors.lastname: Usa
authors.forename: Katsumi
authors.initials: K
authors.lastname: Eguchi
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D007515:Islets of Langerhans / Q000276:immunology*; D008875:Middle Aged; D011379:Prognosis; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000150:complications / Q000276:immunology
chemical_list: D001323:Autoantibodies