Characterization of Adult-Onset Diabetes Patients Positive in 3 Screen ICA (TM) ELISA

Background: The prevalence of diabetes associated antibodies (Ab) in Chinese patients recently diagnosed with adult-onset diabetes and the potential role of autoantibody markers for disease phenotype characterization were studied. Methods: 1383 recent-onset adult diabetic patients (mean age 54 years) were included in the study. Serum samples collected within 12 months from diagnosis were tested using 3 Screen ICA (TM) ELISA (3-Screen) designed for combined measurement of GADAb and/or IA-2Ab and/or ZnT8Ab. 3-Screen positive samples were tested for individual diabetes associated and other organ-specific autoantibodies. Clinical characteristics of patients positive and negative in 3-Screen were analysed. Results: 46/1383 (3.3%) recent-onset adult diabetic patients were positive in 3-Screen. 39/46 (85%) positive patients were positive for at least one of GADAb, IA-2Ab and ZnT8Ab in the individual assays. Furthermore, 16/46 (35%) 3 Screen positive patients were positive for at least one thyroid autoantibody (thyroid peroxidase Ab and/or thyroglobulin Ab and/or thyrotropin receptor Ab) while none for adrenal autoantibody. 17/244 (7%) patients who had ketoacidosis and 19/351 (5.4%) patients on insulin treatment were positive in 3-Screen. 950/1383 patients were classed as phenotypic type 2 diabetes and were ketosis-free and not on insulin treatment at 6 months after diagnosis. 26/950 (2.7%) patients were 3-Screen positive and these patients were leaner with lower fasting C-peptide/insulin level and higher HbA1 level compared to 924 3-Screen negative patients. In an updated homeostatic model assessment (HOMA2), HOMA2-β cell function was significantly lower (p < 0.05) for the 26 positive patients with higher insulin sensitivity and lower insulin resistance compared to negative patients. Overall, a population of diabetes autoantibody positive adult-onset diabetes patients with a characteristic phenotype was identified using 3-Screen ELISA. This may be helpful in management of different populations of patients.