Transfer of autoimmune hypothyroidism following bone marrow transplantation from a donor with Graves' disease.

We describe the transfer of a different autoimmune thyroid disorder by bone marrow transplantation. The donor had euthyroid Graves' disease after treatment with antithyroid drugs and stable oxopthalmos, with persistent thyroid autoantibodies. One year after bone marrow transplant, the recipient developed atrophic autoimmune hypothyroidism. Six months later the donor developed transient subclinical hypothyroidism followed by clinical hyperthyroidism. In both recipient and donor the presence of thyrotropin (TSH)-binding inhibitory immunoglobulins was documented. Although TSH receptor antibodies usually act as a TSH agonist causing thyrotoxicosis, they can also can act as a TSH antagonist causing primary hypothyroidism. This case may be an example of how the same antibody can act as an agonist in the donor and an antagonist in the bone marrow recipient, causing two different autoimmune disorders: primary hypothyroidism in the recipient and Graves' disease in the donor.