Induction of stimulating thyrotropin receptor antibodies after radioiodine therapy for toxic multinodular goitre and Graves' disease measured with a novel bioassay.
BACKGROUND
Radioactive iodine therapy (RaI) in toxic multinodular goitre (TMNG) has been associated with the occurrence of Graves'-like hyperthyroidism. It has been postulated that pre-existing autoimmunity may contribute to this phenomenon.


OBJECTIVE
To study whether RaI induces thyrotropin receptor stimulating antibodies (TSAbs) in the short term in TMNG and whether pre-existing autoimmunity is relevant.


METHODS
Thirty-one patients with relapsing Graves' disease and 17 patients with TMNG, all eligible for RaI.


METHODS
Before and 6 weeks after RaI, sera were collected and analysed for the presence of thyroglobulin (Tg), thyroid peroxidase antibodies (TPO-Abs) and thyrotropin receptor binding antibodies (TBIIs). TSAbs were analysed with a novel high-sensitive luciferase-based bioassay based on the JP-26-26 cell line, which constitutively expresses the TSH receptor.


RESULTS
In Graves' disease, RaI did not induce or increase the levels and proportion of patients with measurable levels of any of the antibodies measured, despite a significant increase in Tg. In contrast, in TMNG, RaI induced TBIIs in three TMNG patients, which was accompanied by measurable TSAbs on one occasion.


CONCLUSIONS
We conclude from the present study that induction of TBIIs and TSAbs may occur shortly after RaI in TMNG and that pre-existing autoimmunity may not be a requirement for the induction of TBIIs, as evidenced by the lack of effect of RaI on TBIIs in Graves' disease.
Hovens
Guido C
GC
Department of Endocrinology, Leiden University Medical Center, Leiden, Netherlands.
Heemstra
Karen A
KA
Buiting
Antoinette M J
AM
Stokkel
Marcel P
MP
Karperien
Marcel
M
Ballieux
Bart E
BE
Pereira
Alberto M
AM
Romijn
Johannes A
JA
Smit
Johannes W
JW
D000328:Adult; D000368:Aged; D000906:Antibodies / Q000737:chemistry*; D001681:Biological Assay / Q000379:methods*; D005260:Female; D006044:Goiter, Nodular / Q000532:radiotherapy*; D006111:Graves Disease / Q000532:radiotherapy*; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008156:Luciferases / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011989:Receptors, Thyrotropin / Q000276:immunology*; D013954:Thyroglobulin / Q000737:chemistry; D013961:Thyroid Gland / Q000473:pathology
D000906:Antibodies; D007457:Iodine Radioisotopes; D011989:Receptors, Thyrotropin; D013954:Thyroglobulin; D008156:Luciferases