Abstract
Alemtuzumab-based conditioning for allogeneic hematopoietic stem cell transplantation (allo-HSCT) effectively reduces graft rejection but may predispose patients to autoimmune complications. We herein report a 30-year-old man with severe aplastic anemia who developed thyroid storm due to autoimmune thyroiditis 6 months after undergoing allo-HSCT with an alemtuzumab-based regimen. Despite prompt engraftment, mixed T-cell chimerism and insufficient immune regulation may have contributed to the early onset and severity of the thyroid storm. Careful monitoring of the thyroid function and immune chimerism might facilitate the early detection and management of post-transplant autoimmune complications, including thyroid storm, in patients receiving alemtuzumab-based conditioning.