| Objective:It has been demonstrated that the pancreatic islet (3cell function decline fast in patients with latent autoimmune diabetes in adults (LADA) who test positive for glutamic acid decarboxylase antibody (GADA). However, the changes of islet function in patients with zinc transporter-8autoantibody (ZnT8A) and protein tyrosine phosphatase2antibodies (IA-2A) positivity remain to be clarified. Thus, the purpose of this study is to observe the changes of islet function in ZnT8A positive and IA-2A positive patients, which can provide some clues for early intervention LADA patients.Subjects and Methods:1. Patients with type2diabetes (T2DM) who had been tested for GADA in endocrine outpatient and ward were enrolled from2005to2008. They were classified as GADA positive LADA and GADA negative T2DM patients and further received ZnT8A and IA-2A tests. All the three antibodies were measuremed by radioligand assay.2. Ten well-documented LADA patients with double positivity for GADA and ZnT8A (GADA+ZnT8A+) were screened out and their average age was49(26-63) years old;12LADA patients with double positivity for GADA and IA-2A (GADA+IA-2A+)were screened out and their average age was52(37-71) years old;4LADA patients with IA-2A positivity alone were selected and their average age was56(53-71) years old;40LADA patients with GADA positivity alone and their average age was51(28-71) years old;42T2DM patients negative for three Abs were selected as the control and their average age was56(30-70) years old.3. The baseline clinical data of all the groups were compared and all the patients were followed once a year for3years. FBG, HbA1C, fasting C-peptide, C-peptide2h after meal, TG, TC, HDL-C and LDL-C were detected and compared in the above groups during the follow-up period.Results:1. The baseline data for body mass index (BMI), FBG and HbAlc in the GADA+ZnT8A+group were all significantly higher than those in T2DM group (P=0.036,0.003and0.018), and the BMI and HbA1c levels were also higher than the patients with GADA+alone. Besides, the level of fasting C-peptide in GADA+ZnT8A+group was observed both lower than those in group with GADA positive alone and T2DM group [301(64-640) pmol/L vs.598(228-2146) pmol/L and643(163-1658) pmol/L, P=0.005and0.006].2. All the baseline data for GADA+IA-2A+group were not significantly different from those in the T2DM group (all.P>0.05). There were also no significant difference for the baselines data between GADA+IA-2A+group and GADA+alone group (all P>0.05).3. As compared with baseline data, there had no statistically significant changes during the3years follow-up period in GADA+ZnT8A positive group (all P>0.05).4. The fasting C-peptide tend to decrease year by year during the follow-up and was statistically lower than the baseline level at the3rd year in GADA+IA-2A+group (P=0.02).5. During the follow-up period, the average rate of decrease in fasting C-peptide annually was more rapid in GADA+IA-2A+group both than those in GADA+alone group and T2DM group (19.5%vs.10.6%,19.5%to0%, P<0.05and P<0.0001).Conclusions:1. The islet function of LADA patients initially tested positive for GADA and ZnT8A are much worse than those of classic T2DM and LADA patients with GADA alone, however, it do not further decline with the disease progress.2. Although the islet function of LADA patients initially tested positive for GADA and IA-2A seem no different with that of T2DM patients, it decline fast with diabetes progress. Since it’s a retrospective study and the size of the sample is small, the above conclusions should be proved in a larger sample size and prospective study in the future. |
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