[Interferon-alpha-induced disorders of thyroid function. A retrospective analysis of the literature and personal experiences].

This paper tries to evaluate the importance of IFN-alpha induced thyroid dysfunction. Based on our own experience and reported data we present the results obtained in a total of 588 patients, in whom thyroid function and thyroid antibody occurrence was monitored during therapy with IFN-alpha: About 10% of these patients developed thyroid dysfunction during IFN-alpha treatment. Half of them reacted with hypothyroidism, 3% with hyperthyroidism and in 2% a biphasic (hyperthyroidism followed by hypothyroidism) pattern of reaction was observed. The frequency of these thyroid dysfunctions was increased in female patients and in patients with preexisting thyroid antibodies. The risk to develop thyroid dysfunction is reduced to 7% in patients with no pretherapeutic thyroid antibodies. The evolution of the thyroid ailment is variable and therefore unpredictable. In many patients there is no need to stop treatment with IFN-alpha nor to treat the thyroid dysfunction specifically. IFN-alpha induced autoimmune- phenomena seem to be etiologically important for the development of thyroid disease during IFN-alpha. The reported data allow in our view some basic recommendations for the clinician: thyroid function and thyroid antibodies should be evaluated before the start of treatment with IFN-alpha. During therapy with IFN-alpha these parameters should be regularly (eg every 4 months) monitored. In patients with thyroid autoantibodies or dysfunction already before IFN-alpha the control intervals should not be longer than every two months.