Type 1 diabetes mellitus with dual autoimmune mechanism related to pegylated interferon and ribavirin treatment for chronic HCV hepatitis.

We report a case of type 1 diabetes mellitus during pegylated interferon and ribavirin treatment for chronic hepatitis C, in a young man previously diagnosed with Hashimoto's thyroiditis and vitiligo. The diabetes mellitus occurred during the 12th month of therapy and the cessation of interferon was necessary. Besides anti-islet autoantibodies our patient had also anti-insulin receptor autoantibodies, which explains the type B insulin resistance. One year after interferon discontinuation the patient continues insulin treatment and all the pancreatic autoantibodies are still positive. Patients with autoimmune disorders should be closely monitored and periodically tested for pancreatic autoantibodies during interferon treatment, even in the absence of hyperglycemia.