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Autoantibodies in children with type 2 diabetes mellitus
Vatcharapan Umpaichitra1, Mary Ann Banerji, Salvador Castells
1Department of Pediatrics, State University of New York Health Science Center at Brooklyn, 11203, USA.
Insights
This study found a low frequency (10.8%) of autoimmune markers like GAD and IA-2 in children with type 2 diabetes mellitus (DM). This supports their classification as type 2 DM based on C-peptide levels.
Area of Science:
- Endocrinology
- Immunology
- Pediatrics
Background:
- Type 2 diabetes mellitus (DM) is increasingly diagnosed in children and adolescents.
- Autoimmunity plays a key role in type 1 diabetes, but its prevalence in pediatric type 2 DM is less understood.
- Autoantibodies such as glutamic acid decarboxylase (GAD), islet antigen-2 (IA-2), and insulin autoantibodies (IAA) are markers of autoimmune processes in diabetes.
Purpose of the Study:
- To determine the frequency of autoantibodies to GAD, IA-2, and IAA in a cohort of children and adolescents diagnosed with type 2 DM.
- To assess the autoimmune profile in pediatric patients classified as type 2 DM based on C-peptide levels.
Main Methods:
- Studied 37 children and adolescents with type 2 DM, defined by specific C-peptide levels after a liquid meal.
- Assessed serum autoantibodies for GAD, IA-2, and IAA using immunoassay techniques.
- Analyzed the association between autoantibody positivity and clinical characteristics, including insulin treatment.
Main Results:
- Overall, 29.7% of patients (11/37) were positive for at least one autoantibody.
- Prevalence of specific autoantibodies: GAD (8.1%), IA-2 (8.1%), and IAA (27%).
- After excluding IAA due to insulin treatment influence, 10.8% (4/37) of patients were positive for GAD and/or IA-2, considered primary autoimmune markers.
Conclusions:
- The low frequency (10.8%) of GAD and IA-2 autoantibodies in this cohort supports the clinical classification of type 2 DM in these children and adolescents.
- The findings suggest that autoimmune diabetes is uncommon in pediatric patients presenting with features of type 2 DM and preserved C-peptide secretion.
- Further research may be needed to fully elucidate the role of autoimmunity in the pathogenesis of type 2 DM in the pediatric population.
Abstract:
To evaluate the frequency of autoantibodies to glutamic acid decarboxylase (GAD), protein tyrosine phosphatase-like protein (IA-2), and insulin (IAA) in children with type 2 diabetes mellitus (DM), we studied 37 children and adolescents whose type 2 DM was defined by fasting and 90-min standard liquid meal-stimulated serum C-peptide levels of >0.2 and >0.5 nmol/l (0.7 and 1.5 ng/ml), respectively. Mean fasting-stimulated serum C-peptide levels were 1.1 +/- 0.10 nmol/l (3.38 +/- 0.29 ng/ml) and 1.9 +/- 0.17 nmol/l (5.79 +/- 0.50 ng/ml), respectively. Eleven out of 37 patients (29.7%) were positive for at least one autoantibody: 8.1% (n = 3) had positive GAD, 8.1% (n = 3) had positive IA-2, and 27% (n = 10) had positive IAA. Nine of the 10 IAA-positive patients were on insulin treatment at the time of testing. Three of the 10 IAA-positive patients were also positive for GAD or IA-2. Since insulin treatment can stimulate IAA, we considered this to be less informative in classifying autoimmunity in DM. Therefore, GAD and IA-2 were considered primary autoimmune markers. Four out of 37 patients (10.8%) were positive for GAD (n = 3) or IA-2 (n = 3) or both (n = 2). Thus, low (10.8%) frequency of autoimmunity in children and adolescents is consistent with their clinical classification of type 2 DM based on the presence of residual C-peptide.