Type 1 diabetes mellitus (T1DM) is a
chronic disease characterized by autoimmune destruction of pancreatic beta cells and inadequate
insulin production. Remission criteria in T1DM take into account serum levels of
C-peptide and
glycosylated hemoglobin, as well as the dose of
insulin administered to the patient. However, remission of T1DM lasting longer than 1 year is rare. We describe here the cases of two young women who presented with positive
glutamic acid decarboxylase (GAD) antibody and classic clinical manifestations of T1DM. Both patients had a prior history of Hashimoto's
thyroiditis. They were initially treated with a basal-bolus regimen of
insulin (glargine and
lispro/glulisine). Once their
blood glucose levels were controlled, they were started on oral
sitagliptin 100 mg and
vitamin D3 5000 IU daily. After this
therapy, both patients achieved clinical diabetes remission for 4 years, along with a decrease in anti-GAD antibody levels. These benefits were probably associated with immunological effects of these medications. Inhibition of
dipeptidyl peptidase 4 (DPP-4) in animal models deregulates Th1 immune response, increases secretion of Th2
cytokines, activates CD4+CD25+FoxP3+ regulatory T-cells and prevents
IL-17 production.
Vitamin D3 also activates CD4+CD25+FoxP3+ regulatory T-cells, and these medications combined can improve the immune response in patients with new-onset T1DM and probably promote sustained clinical remission.
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