The change of serum TRAb after 131I radiotherapy in patients of Graves' hyperthyroidism

Objective: The clinical value of thyrotrophin receptor antibody (TRAb) in patients with Graves' hyperthyroidism was investigated during 131I radiotherapy. Methods: A total of 130 patients with Graves' hyperthyroidism and 50 normal controls were included in the study. Serum concentration of TRAb was measured by radioreceptor assay (RRA) before and at 3, 6, 12 and 24 months after 131I radiotherapy. Results: Abnormally higher TRAb level [(92.93±68.99)U/L] was noted in patients before treatment(P<0.01). The TRAb titer increased further to (139.04±77.19) U/L at 3 months after therapy (P <0.01 ), before it dropped to (65.87±54.86) U/L and (14.16±12.35) U/L at 6 and 12 months respectively. At 24 months after 131I radiotherapy, the TRAb [(12.99±5.52) U/L] was back to normal with no difference to that of controls (P>0.05). Conclusion: Serum concentration of TRAb was of clinical significance in the diagnosis of Graves' hyperthyroidism and in the monitoring of 131I radiotherapy. (authors)