Glutamic acid decarboxylase autoantibodies are dominant but insufficient to identify most Chinese with adult-onset non-insulin requiring autoimmune diabetes: LADA China study 5

• DOI: 10.1007/s00592-015-0799-8
• Publication Date: 2015-08-03T21:35:54Z
• Authors: Yufei Xiang; Gan Huang; Zhongyan Shan; Linlin Pan; Shuoming Luo; Liyong Yang; Lixin Shi; Qifu Li; R. David Leslie; Zhiguang Zhou
• Keywords: Asian Continental Ancestry Group; Adult; Male; China; Endocrinology, Diabetes and Metabolism; Zinc Transporter 8; Latent autoimmune diabetes of adults (LADA); Islets of Langerhans; 03 medical and health sciences; Endocrinology; 0302 clinical medicine; Asian People; Diabetes Mellitus; Internal Medicine; Prevalence; Humans; Protein Phosphatase 2; Insulin autoantibody (IAA); Cation Transport Proteins; Aged; Autoantibodies; Glutamate Decarboxylase; Glutamic acid decarboxylase antibody (GADA); Middle Aged; 3. Good health; Diabetes Mellitus, Type 2; Protein tyrosine phosphatase-2 antibody (IA-2A); Original Article; Female; Type 2; Biomarkers; Zinc transporter 8 autoantibody (ZnT8A)

Adult-onset autoimmune diabetes is prevalent in China, in contrast to childhood-onset type 1 diabetes mellitus. Islet autoantibodies are the most important immune biomarkers to diagnose autoimmune diabetes. We assayed four different islet autoantibodies in recently diagnosed adult non-insulin-requiring diabetes Chinese subjects to investigate the best antibody assay strategy for the correct diagnosis of these subjects.LADA China study is a nation-wide multicenter study conducted in diabetes patients from 46 university-affiliated hospitals in China. Non-insulin-treated newly diagnosed adult diabetes patients (n = 2388) were centrally assayed for glutamic acid decarboxylase autoantibody (GADA), protein tyrosine phosphatase-2 autoantibody (IA-2A), and zinc transporter 8 autoantibody (ZnT8A) by radioligand assay and insulin autoantibody (IAA) by microtiter plate radioimmunoassay. Clinical data were determined locally.Two hundred and six (8.63 %) subjects were autoantibody positive, of which GADA identified 5.78 % (138/2388) of the total, but only 67 % (138/206) of the autoimmune cases. IA-2A, ZnT8A, and IAA were found in 1.51, 1.84, and 1.26 % of the total study subjects, respectively. When assaying three islet autoantibodies, the most effective strategy was the combination of GADA, ZnT8A, and IAA, which could identify 92.2 % (190/206) autoimmune diabetes patients. The clinical data showed that those subjects with positive GADA had lower random C-peptide than autoantibody negative subjects (P < 0.05).As with Europeans, GADA is the dominant autoantibody in this form of autoimmune diabetes in China, but in contrast to Europeans, screening should include other diabetes-associated autoantibodies.