Carboxypeptidase‐H Autoantibodies Differentiate a More Latent Subset of Autoimmune Diabetes from Phenotypic Type 2 Diabetes among Chinese Adults

Abstract

This study aimed to investigate whether carboxypeptidase-H antibody (CPH-Ab) can help identify latent autoimmune diabetes in adults (LADA). Phenotypic type 2 diabetic (T2D) patients (n= 1296) were studied for CPH Abs and autoantibodies to glutamic acid decarboxylase (GAD-Abs). CPH-Ab(+) T2D patients also underwent testing for insulinoma protein tyrosine phosphatase (IA-2A). Clinical features were compared among CPH-Ab(+), GAD-Ab(+), and Ab(-) T2D patients. Some of the antibody-positive patients were followed up for 3 years to assess beta cell function. The prevalence of CPH-Abs in T2D patients was 4.8%, significantly higher than that in controls. Double positivity was rare between CPH-Abs and GAD-Abs or IA-2A. Compared to patients with Ab(-) T2D, those with CPH-Ab(+) T2D had lower BMI, lower fasting C-peptide (FCP) levels, and more frequent ketosis, while not as much as did those with GAD-Ab(+) T2D. The mild beta cell dysfunction in patients with CPH-Ab(+) T2D was associated with their longer duration of diabetes. No marked change of C-peptide in the CPH-Ab(+) group was found during follow-up. These findings demonstrated that CPH-Abs may allow discrimination of a more latent subset of adult-onset autoimmune diabetes (LADA) whose features are intermediate between those with classic GAD-Ab(+) LADA and patients with Ab(-) T2D.

Latent autoimmune diabetes in adults in China

“…Chinese LADA screening is often based on GADA combined with IA-2A, ZnT8A, and IAA detection to improve diagnostic sensitivity. In addition, Chinese LADA may also have transmembrane protein 7 (Tspan) autoantibodies ( 38 ), carboxypeptidase H (CPH-A) autoantibodies ( 41 ), and transcription factor Syr-Box transcription factor (SOX13) antibodies ( 39 ). SOX13-A was found in 7.0% of Caucasian individuals with LADA ( 40 ), which was lower than that found in the Chinese ( 39 ).…”

Latent autoimmune diabetes in adults in China: clinical features and epidemiology

“…本研究组 [13,29] 及意大 利的NIRAD研究项目 [30] [31] . 另一类胰岛自身抗体, 羧基肽酶H抗体(CPH-Ab) 阳性的患者, 疾病进展则介于GADA阳性的LADA患 者和抗体阴性的T2DM患者之间 [32] . 除此之外, 实施治 疗和指导的医生个人意见也影响了每个患者LADA疾 病的进程, 而启动胰岛素治疗的时间亦影响着LADA 患者的预后, 在疾病早期开始胰岛素治疗可以有效保 护胰岛功能 [33] .…”