Elevation of anti-DNA antibody titer during thyrotoxic phase of silent thyroiditis

The elevation of anti-DNA antibody titers was observed in two cases of silent thyroiditis; the levels reverted to normal as thyrotoxicosis improved. Biopsy specimens of the thyroid gland revealed chronic lymphocytic thyroiditis. The elevation of anti-DNA antibody titers during the thyrotoxic phase of silent thyroiditis, to our knowledge, has not been reported. In one case, antinuclear antibody testing was also positive during the thyrotoxic phase and became negative in the euthyroid state. These observations provide further support for autoimmunity in silent thyroiditis.