THYROID-FUNCTION IN CHILDREN AFTER ALLOGENEIC BONE-MARROW TRANSPLANTATION

Thyroid function was investigated in 35 children after allogeneic BMT. The study was longitudinal and all patients were followed for at leas t 5 years. Once a gear TSH, T4, T3 and the TRH test were performed. Pa tients with severe aplastic anemia (n = 6) were transplanted without t otal body irradiation (TBI) and they had no detectable alterations in thyroid function. Patients with leukemia (n = 27) were conditioned wit h 10 Gy TBI in one fraction. The accumulated frequencies of thyroid dy sfunction were 3 of 27 (11%) with high TSH and low T3 or T4 levels, an d 10 of 27 (37%) with high basal TSH and normal T3 and T4 levels. An a dditional 11 of 27 (41%) had an exaggerated TSH response in the TRH te st and normal basal TSH and T3/T4 levels. Only 3 of 27 (11%) continued to have normal values. Treatment with levo-thyroxine (L-T4) was given to the patients with a high basal TSH level. As 24 of 27 (89%) childr en had signs of disturbance in the thyroid axis, prophylactic L-T4 tre atment for a few years after BMT with TBI may be of value. The main ca use of a change in thyroid function after BMT seems to be conditioning with TBI.