A Case of Type C Chronic Hepatitis Developing Type 1 Diabetes Mellitus Two Years Later after Interferon Therapy with Appearance of Anti-GAD Antibody

Abstract

A woman born in 1962 underwent 6 month-therapy with interferon (IFN) from July 1999 for type C chronic hepatitis. Diabetic ketoacidosis (DKA) developed in May 2002 and insulin treatment was begun. Plasma glucose level (mg/dl) was less than 110 until the end of 2001, but had been 154 four months before, 327 two weeks before, and 568 at the DKA event. She then became insulin-dependent and her daily insulin injection was increased to 52 units. As anti-GAD antibody, ICA, and IA-2 antibody were all positive, she was diagnosed as having type 1 diabetes mellitus. Anti-GAD antibody was negative before and during IFN therapy, but was 23.3 U/ml, and thus positive in January 2000 immediately after the end of therapy. It remained positive until diabetes mellitus developed. She had class II HLA antigens of DRB1^*0901, DQB1^*0302, and DQB1^*0303, which reflected the susceptibility to type 1 diabetes mellitus in the Japanese population. The present case suggests that screening for anti-GAD antibody may enable us to predict and prevent the development of type 1 diabetes in patients undergoing IFN therapy.