[Islet beta cell function in latent autoimmune diabetes in adults with islet cell antibodies].
OBJECTIVE
To explore the predictive value and influence of islet cell antibody (ICA) and glutamic acid decarboxylase antibody (GAD-Ab) for beta cell function in latent autoimmune diabetes in adults (LADA) patients.


METHODS
Fifty-six patients with initially diagnosed type 2 diabetes (including 10 cases of GAD-Ab-positive alone, 14 ICA-positive alone, 7 GAD-Ab and ICA-positive and 25 GAD-Ab and ICA negative) were followed up every 6 months (except the 2nd year) until the 5th year. Their fasting and postprandial C-peptide and glycemic control were measured. GAD-Ab was determined by radioimmunoprecipitation assay and ICA by ELISA kit.


RESULTS
Decreased fasting C-peptide was found in patients with GAD-Ab alone and patients with GAD-Ab and ICA in the 2.5th year and to the end of the follow-up. The percentage of patients whose C-peptide decreased 50% or more compared with the baseline in the above 2 groups reached 60.0% in the 3nd year and 71.4% in the 3.5th year, respectively. No changes of the above parameters were found in ICA-positive alone group and GAD-Ab and ICA negative group. Complete beta-cell failure was found in 4 of the 10 patients in GAD-Ab alone group and in 1 of the 10 patients in ICA and GAD-Ab positive group. The number of failure patients in GAD-Ab alone group was more than that of the other 2 groups (P < 0.05 in both groups). There was no significant correlation between ICA index and FCP. Multiple stepwise regression analysis demonstrated that GAD-Ab contributed much more to FCP than ICA did.


CONCLUSIONS
The islet beta cell function decreases more quickly in GAD-Ab positive LADA patients than in ICA positive ones. The titer of GAD-Ab is an important prognostic factor in islet beta cell function, and the presentation of ICA-positive alone can not predict beta cell function in LADA patients.
Yang
Lin
L
Institute of Metabolism and Endocrinology, Second Xiangya Hospital, Central South University, Changsha 410011, China.
Zhou
Zhi-Guang
ZG
Huang
Gan
G
Yan
Xiang
X
D000293:Adolescent; D000328:Adult; D000906:Antibodies / Q000097:blood*; D001323:Autoantibodies / Q000097:blood*; D001327:Autoimmune Diseases / Q000276:immunology / Q000503:physiopathology; D003920:Diabetes Mellitus / Q000276:immunology* / Q000503:physiopathology; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D007515:Islets of Langerhans / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged
D000906:Antibodies; D001323:Autoantibodies; C024211:islet cell antibody; D005968:Glutamate Decarboxylase