Hashimoto's disease during interferon-alpha therapy in a patient with pre-treatment negative anti-thyroid autoantibodies and with the specific genetic susceptibility to the thyroid disease.

OBJECTIVES: The authors described a case of Hashimoto's disease during interferon-alpha (IFN-alpha) treatment for chronic viral C hepatitis in a patient with the specific genetic susceptibility associated with the thyroid disease.

RESULTS: A 60-year-old woman with chronic active viral C hepatitis (HCV genotype = 3a) started IFN-alpha therapy in November '96. Before treatment thyroid function tests were normal and anti-thyroid (anti-thyroglobulin and anti-thyroid peroxidase) Abs were negative. During IFN therapy, serum aminotransferases fell within the normal range and viremia (serum HCV-RNA) became negative after one year. After 20 months, the patient presented clinical features of primary hypothyroidism. Anti-thyroid Abs were found positive. Hormonal, ultrasonographic, radioiodine scanning and fine needle aspiration findings were consistent with the diagnosis of Hashimoto's thyroiditis. The tissutal typing of the patient showed the presence of Human Leukocyte Antigen (HLA) DRB1*11 gene (corresponding to DR5 antigen). IFN-alpha therapy was suspended and a treatment with l-T4 started. Chronic viral infection relapsed after the suspension of the IFN-alpha therapy.

CONCLUSIONS: This case report showed that the clinical appearance of Hashimoto's disease after IFN-alpha therapy for chronic C hepatitis in our patient was associated with a specific genetic predisposition (DR5) for this pathology. Further studies are necessary to evaluate whether the study of HLA antigens may be a very useful tool to detect the patients with a predisposition to develop autoimmune thyroiditis, in order to make a early diagnosis of thyroid disorders during the IFN-alpha treatment.