Case ReportSitagliptin in Glutamic Acid Decarboxylase Antibody-Positive Diabetes Mellitus
Section snippets
INTRODUCTION
Dipeptidyl-peptidase-4 (DPP-4) inhibitors lower the blood glucose level in patients with type 2 diabetes mellitus by inhibiting the degradation of endogenous glucagonlike peptide-1 (GLP-1) and thus enhancing GLP-1 action. DPP-4 has 62 endogenous substrates and is present in lymphocytes as CD26 (1). The effect of DPP-4 inhibition on the immune system has not been well studied. We describe the case of a woman with glutamic acid decarboxylase (GAD) antibody-positive diabetes mellitus, autoimmune
CASE REPORT
A 68-year-old Japanese woman presented in 2006 with poorly controlled “type 2” diabetes of 10 years’ duration. Her medical history included cerebral palsy and primary hypothyroidism.
The patient’s neurologic symptoms were stable until 1998, after which her mobility gradually worsened, accompanied by increasing cerebellar ataxia. Her glycemic control progressively deteriorated during a period of 2 years from an A1C level of less than 7.5% (58 mmol/mol) before 2000 to greater than 10% (86
DISCUSSION
This case suggests a possible role for sitagliptin in improving glycemic control in patients with GAD antibody-positive diabetes. In addition to the effects of sitagliptin on insulin secretion, we explore other mechanisms by which sitagliptin may improve glycemia.
DPP-4 is present in the immune system as CD26 on lymphocytes. It is an activation marker for T lymphocytes, B lymphocytes, and natural killer cells (1). Its immunoregulatory functions include antigen recall, immunoglobulin synthesis,
CONCLUSION
This case raises the potential for use of DPP-4 inhibitors in patients with GAD antibody-positive or autoimmune diabetes. We acknowledge that our experience is based on a single case, and further studies are needed to explore this potentially useful therapeutic role of DPP-4 inhibitors.
DISCLOSURE
The authors have no multiplicity of interest to disclose.
ACKNOWLEDGMENT
We thank Dr Angela Vincent, Professor of Neuroimmunology, University of Oxford, for her helpful advice on the immunologic aspects of this case.
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