Two Years of Modified Protocol with Cyclosporin A for Treatment of Acute Insulin Resistance Induced by Anti-Glutamic Acid Decarboxylase (GAD) Antibodies in Obese Type II Diabetics

Background: Diabetes mellitus (DM) is a disease characterized by hyperglycemia due to (a) insulin-insufficiency (type I DM), or (b) impaired glucose cell-entry (insulin resistance) due to the downregulation of insulin cell receptors (type II DM). Type I DM usually presents with florid manifestations contrary to a slowly-progressive type II. Patients and methods: Over the past 10 years, we encountered 9 obese patients with controlled insulin-requiring type II DM for years, at a dose of 62 ± 5 units/day, who developed sudden and severe insulin resistance (IR) that required 210 ± 25 units daily. All patients had very high levels of anti-Glutamic Acid Decarboxylase (GAD) antibodies. Despite a lack of previous testing for anti-GAD antibodies, they were treated, with Cyclosporin A (Cy), as an autoimmune disorder superimposed on their type II MD. Initially all patients were treated with 100 mg, of Cy, twice daily aiming at an initial trough level of 100 - 150 ng/ml. Three months later, the dose was reduced to 50 mg twice daily for a total of 2 years. Results: Amelioration of IR was achieved by 1 month with a reduction of daily insulin requirement to 123 ± 16 units that further decreased to 76 ± 11 by the end of the 3^rd month. Such improvement persisted for 2 years and >1 year after Cy discontinuation. Moreover, a decline in insulin requirements was associated with a parallel decrease in anti-GAD antibody levels and an increase in C-peptide insulin without kidney disease. Conclusion: Anti-GAD antibodies can induce acute IR in type II DM, and this phenomenon can be treated safely and effectively with Cy.