Inhibition of Insulin Release In Vitro Mediated by Mononuclear Cells From Diabetic Patients Treated With Cyclosporin A or Placebo

Anti-β-cell–specific cell-mediated immunity was studied over a 12-mo period in 65 recently diagnosed diabetic patients randomly receiving either cyclosporin or placebo. Anti-β–cell cellular immunity was assessed by an in vitro test based on the inhibition of insulin release from cultured rat islet cells by patients' mononuclear cells. This β-cell–suppressive effect disappeared in cyclosporin A–treated patients within 1 mo and did not reappear during 12 mo of follow-up. Conversely, the suppressive effect persisted unchanged in placebo-treated patients during 12 mo of follow-up. These changes were predictive neither of cyclosporin A–induced remission nor of relapses. Results of the insulin-release inhibition test were not correlated to islet cell autoantibodies or HLA phenotype.