Islet-cell antibodies and type 1 diabetes after treatment with interferon-alpha

Background and objective: The aim of this study was to study the appearance of autoantibodies against islet cells and the development of type 1 diabetes in patients with chronic hepatitis C during interferon treatment. Patients and methods: 74 patients (24 women, 50 men, mean age: 46 years) with HCV infection were treated with interferon, ribavirin and amantadin versus placebo, after they had failed to previous interferon therapy in a prospective, randomised trial. At the end of treatment period anti-islet cell autoantibodies (anti-GAD, anti IA-2), anti-insulin antibodies, TSH, anti-thyroid autoantibodies (TPO, thyreoglobulin, TSH-receptor antibodies) were measured. Results: In two patients, GAD autoantibodies were found, but both patients were negative for IA-2 and insulin antibodies. One of the patients developed type 1 diabetes five months after start of treatment. In this patient, the anti-GAD titer was initial 0 U/ ml (normal: < 1.2). The titer raised to 52,2 U/ml after the interferon monotherapy. During the second interferon treatment (in combination) the titer raised from initial 41,1 U/ml to 59,6 U/ ml. The anti-GAD titer of the second patient was 0 U/ml before treatment and raised to 1,7 U/ml. This patient did not develop a type 1 diabetes. Conclusion: Type 1 diabetes is a rare but serious complication of interferon therapy. Repetitive treatment seems to facilitate this complication. Screening for islet antibodies before a second therapy could be useful.