胰岛细胞抗体阳性的成人隐匿性自身免疫糖尿病患者的胰岛β细胞功能

目的：探讨胰岛细胞抗体（ICA）和谷氨酸脱羧酶抗体（GAD-Ab）对成人隐匿性自身免疫糖尿病（LADA）患者胰岛功能的影响和预测价值。方法：对单独ICA阳性的LADA14例，单独GAD-Ab阳性的LADA 10例，GAD-Ab和ICA同时阳性的LADA 7例，两抗体均阴性的2型糖尿病（T2DM）25例，每半年随访一次（第2年除外）直至第5年，测定患者空腹C肽（FCP）和100 g馒头餐后2 h C肽（2°CP）及糖代谢指标。采用放射免疫法测定GAD-Ab和C肽，酶联免疫吸附法（ELISA）测定ICA。结果：单独GAD-Ab阳性和两抗体均阳性组的FCP从随访第2.5年开始下降，FCP较入组时下降≥50%的患者百分比分别从第3年和第3.5年升至60%和71.4%，单独ICA阳性组和抗体阴性的T2DM组则无显著性变化。单独GAD-Ab阳性组中4/10例、两抗体均阳性组1/10例出现胰岛功能衰竭，前者与单独ICA阳性组(0/14例)和两抗体均阴性组（0/25例）比较有统计学意义（均P﹤0.05）。ICA与FCP间无显著性相关（rs = -0.258，P﹥0.05），多元回归分析显示GAD-Ab对FCP的影响远大于ICA。 结论：GAD-Ab阳性的LADA患者胰岛β细胞功能较ICA阳性的LADA以及T2DM下降更快，GAD-Ab滴度是预测胰岛功能减退速度的重要因素，而单一出现的ICA对于LADA胰岛功能不具有预测作用。

Islet β cell function in latent autoimmune diabetes in adultswith 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. CONCLUSION: 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.