Emergence of anti-islet autoantibodies in Japanese patients with type 1 diabetes

• Published in: Endocrine Journal 2010, Vol.57(7), pp.623-628
• Main Authors: Horie, Ichiro, Kawasaki, Eiji, Shimomura, Aya, Satoh, Tsuyoshi, Ueki, Ikuko, Kuwahara, Hironaga, Ando, Takao, Abiru, Norio, Usa, Toshiro, Eguchi, Katsumi
• Format: Article
• Language: English
• Subjects: Adult; Anti-islet autoantibodies; Autoantibodies - blood; Autoimmune polyglandular syndrome type 3; Diabetes Mellitus, Type 1 - blood; Diabetes Mellitus, Type 1 - complications; Diabetes Mellitus, Type 1 - diagnosis; Diabetes Mellitus, Type 1 - immunology; Disease Progression; Female; GAD65; Humans; Islets of Langerhans - immunology; Middle Aged; Prediction; Prognosis; Thyroiditis, Autoimmune - blood; Thyroiditis, Autoimmune - complications; Thyroiditis, Autoimmune - immunology; Type 1 diabetes
• ISSN: 0918-8959; 1348-4540
• DOI: 10.1507/endocrj.K10E-068

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.