Autoimmune thyroiditis and myelosuppression following treatment with interferon-alpha for hepatitis C

We describe the case of a 48-year-old woman from Thailand diagnosed with chronic hepatitis C, who experienced a suppression of all blood cell counts accompanied by a newly developed clinically manifested autoimmune thyroid disorder after treatment with interferon alpha-2b (INF-alpha) 46 days after beginning of therapy a decrease of platelet, red and white blood cell counts became obvious. Concomitantly we observed an increase of FT4 and FT3 with a totally depressed TSH level 80 days after starting INF-alpha administration. Antibody assessment resulted in detection of high numbers of antithyroid-microsomal antibodies and antithyroglobulin antibodies. Thyroid hormone levels normalized under treatment with methimazole/propylthiouracil within 4.5 months. However, two months after cessation of antithyroid therapy increasing TSH levels and decreasing FT4 levels indicated a new tendency towards a hypothyroid state.

We classify this case as an interferon-alpha-induced disorder of thyroid function accompanied by myelosuppression. A close monitoring for thyroid dysfunction, e.g. evaluation of TSH-levels before and after administration of INF-alpha is mandatory.