| Objective:To explore the distribution and clinical features of zinc transporter 8 autoantibody (ZnT8A) positive latent autoimmune diabetes patients in adults(LADA) in phenotypic type 2 diabetic population, and to find diagnostic and screening value of ZnT8A for LADA.Subjects and Methods:A total of 3062 phenotypic type 2 diabetic patients were randomly selected from patients participating LADA-China study,405 healthy cases were also included as controls. ZnT8A, glutamic acid decarboxylase antibody(GADA), protein tyrosine phosphatase-2 antibody(IA-2A) were determined by radioligand assay(RLA). The distribution of ZnT8A and its diagnostic value alone or in combination with GADA, IA-2A was explored, and clinical features, including HbA1c, fasting C peptide, serum lipid levels were also studied in ZnT8A positive patients.Results:1. The positive prevalence of ZnT8A, GADA and IA-2A in phenotypic type 2 diabetes was 1.99%(61/3062),6.43%(197/3062), 1.96%(60/3062) respectively. The ZnT8A positivity was lower than that of GADA (1.99% vs 6.43%,χ=74.8, P＜0.001), but was comparable to that of IA-2A (1.99% vs 1.96%, P>0.05), which displayed no significant difference between males and females (2.08% vs 1.86%, P>0.05).2. The positivity for single ZnT8A was 1.05% in phenotypic type 2 diabetes, and the combination positivity of ZnT8A in IA-2A positive patients was higher than that in GADA positive patients (38.3% vs 10.7%, x2=24.8, P＜0.001).3. Based on testing of GADA and IA-2A, combination determination of ZnT8A could increase the diagnostic sensitivity from 7.57% to 8.62%.4. The clinical features showed no significant difference between ZnT8A positive LADA and negative type 2 diabetic patients.5. ZnT8A positive patients had higher systolic blood pressure when compared with GADA positive LADA (P=0.012); and higher total cholesterol (TC) levels when compared with all autoantibodies negative group (P=0.026).6. Patients who were positive for GADA and ZnT8A had higher BMI than GADA positive alone group (P=0.030)Conclusions:A certain proportion of ZnT8A positive LADA patients can be found in phenotypic type 2 diabetes, it tend to combine with IA-2A. The determination of ZnT8A at the basis of GADA,IA-2A, can increase diagnostic sensitivity of LADA. The clinical features of ZnT8A positive LADA patients are close to those of classic T2DM, which should be confirmed by further follow-up study. |
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