Early changes in thyroid-stimulating antibody activity following radioiodine therapy.
OBJECTIVE
The aim of this study was to determine whether or not the titre of thyroid-stimulating hormone receptor antibody with stimulating (TRAb-S) activity changes in patients with Graves' disease (GD) or toxic multinodular goitres (TMNG) 3 months after treatment with sodium iodide ((131)I).


METHODS
Serum specimens were obtained from 21 hyperthyroid patients (15 with GD and 6 with TMNG) at a median 0.5 months before and 3 months after (131)I treatment using a standard ablative dose of 555 MBq. TRAb-S activity was measured in a sensitive and specific luminescent bioassay employing the lulu cell line and expressed as a stimulation index (SI; normal </=1.5).


RESULTS
The mean TRAb-S in the GD patients was 2.72 SI (95% CI: 1.51-4.03) 0.5 months before administration of (131)I and 3.98 SI (95% CI: 1.20-6.76) 3 months after administration of (131)I. The difference was not statistically significant at p LT; 0.8. It was not elevated in the TMNG patients before (0.57 SI; 95% CI: 0.41- 0.73) and after (1.00 SI; 95% CI: 0.74-1.26) treatment either.


CONCLUSIONS
Radioiodine therapy for GD or TMNG did not induce a significant change in TRAb-S activity at 3 months after treatment with (131)I, probably due to effective antithyroid therapy or the timing of samples.
Syed
Akheel A
AA
Department of Medical Biochemistry, University Hospital of Wales and University of Wales College of Medicine, Cardiff, UK. a.a.syed@ncl.ac.uk
Evans
Carol
C
Ludgate
Marian
M
Lazarus
John H
JH
D000818:Animals; D001681:Biological Assay; D016466:CHO Cells; D006224:Cricetinae; D006044:Goiter, Nodular / Q000276:immunology / Q000532:radiotherapy*; D006111:Graves Disease / Q000276:immunology / Q000532:radiotherapy*; D006801:Humans; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood*; D066298:In Vitro Techniques; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D012974:Sodium Iodide / Q000627:therapeutic use*
D018828:Immunoglobulins, Thyroid-Stimulating; D007457:Iodine Radioisotopes; D012974:Sodium Iodide