Autoimmune thyroiditis after bone marrow transplantation.

We describe the transfer of autoimmune thyroiditis by bone marrow transplantation. The male recipient developed compensated hypothyroidism 3 years after transplantation, and progressed to thyroid failure 1 year later. The female sibling had compensated hypothyroidism when screened 4 years after marrow donation. The donor, the recipient, and an older male sibling were HLA DR4, 5; the father was presumed homozygous for DR4 and the mother for DR5. Only the donor and recipient had abnormal thyroid function and positive antithyroid antimicrosomal antibodies. The most probable mechanism for the organ specific autoimmune dysfunction is the transfer of abnormal B and T cell clones from the donor. Radiation damage to the thyroid prior to transplantation, the mild graft-versus-host disease immediately following transplantation, and the general immune dysregulation seen in the first several years after marrow engraftment may have contributed to an acceleration of the autoimmune destruction of the recipient's thyroid.