New-onset type 1 diabetes mellitus and anti-aquaporin-4 antibody positive optic neuritis associated with type 1 interferon therapy for chronic hepatitis C.

A 60-year-old woman developed type 1 diabetes mellitus and anti-aquaporin-4 antibody positive optic neuritis during type 1 interferon therapies for chronic hepatitis C. The diabetes mellitus was elicited by interferon-α plus ribavirin therapy, while the optic neuritis was induced after interferon-β treatment, followed by interferon-α and ribavirin therapy. It is possible that type 1 interferons lead to the onset of the two autoimmune diseases by inducing disease-specific autoantibodies. Autoimmune disease is an infrequent complication of type 1 interferon treatment; however, once it has occurred, it may result in severe impairments. Patients undergoing type 1 interferon therapy should therefore be carefully monitored for any manifestations of autoimmune diseases.