PSAT341 Hashimoto's Thyroiditis After Allogenic Bone Marrow Transplantation

INTRODUCTION: Hashimoto's thyroiditis or chronic lymphocytic thyroiditis is a common autoimmune-mediated thyroid disease triggered by an inappropriate T and B cells response. We present a case of a female without personal or family history of autoimmune disease, who developed Hashimoto's thyroiditis with severe hypothyroidism after undergoing bone marrow transplant (BMT). CLINICAL CASE: A 57-year-old woman with hypoplastic myelodysplastic syndrome (MDS) was initially started on immunosuppressive therapy, complicated by autoimmune hemolytic anemia and thrombocytopenia. Three years after diagnosis, she underwent allogenic BMT from a matched unrelated donor. A year later, she presented with weight gain, fatigue, cold intolerance, insomnia, eye puffiness and lower extremity weakness, developed over a month. Exam was notable for periorbital edema and delayed DTRs. Laboratory workup revealed an elevated TSH at 302 µIU/mL (0.27-4.2) with undetectable free T4 and total T4 levels and elevated anti-thyroglobulin antibodies of 2698 IU/mL (0-40) and antiTPO antibodies of 90 IU/mL (0-35). Cortisol was normal at 14 µg/dL. TSH was normal prior to the BMT. Thyroid ultrasound revealed a normal-sized thyroid with a slightly heterogeneous echotexture, suggestive of thyroiditis without distinct nodules. Myxedema coma was ruled out at the time of diagnosis. The patient was started on levothyroxine and noticed a significant improvement of her symptoms within few weeks. Our patient does not have a personal or family history of thyroid disease or other autoimmune disorders. She did not receive radiation treatment or steroid treatment prior to her hypothyroidism diagnosis. She had an RSV upper respiratory infection two months prior to the diagnosis of hypothyroidism without associated neck pain. The clinical and biochemical picture suggest that her hypothyroidism could be related to her allogenic BMT. The presumed mechanism for the autoimmune thyroid dysfunction noted in this patient is the transfer of autoantibodies and donor lymphocytes during BMT. CONCLUSION: Adoptive autoimmune hypothyroidism can occur post-BMT, especially if the donor has genetic susceptibility. It is now accepted that autoimmune thyroiditis can be transferred from donors to recipients during BMT. REFERENCE: Buxbaum NP, Pavletic SZ. Autoimmunity Following Allogeneic Hematopoietic Stem Cell Transplantation. Front Immunol. 2020 Aug 25;11: 2017. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.