Horm Metab Res 2019; 51(06): 341-346
DOI: 10.1055/a-0914-0535
Endocrine Care
© Georg Thieme Verlag KG Stuttgart · New York

Comparison of a Bridge Immunoassay with Two Bioassays for Thyrotropin Receptor Antibody Detection and Differentiation

Stephanie Allelein*
1   Medical Faculty, Division for Specific Endocrinology, University of Düsseldorf, Düsseldorf, Germany
,
Tanja Diana*
2   Department of Medicine I, Molecular Thyroid Research Laboratory, Johannes Gutenberg University (JGU) Medical Center, Mainz, Germany
,
Margret Ehlers
1   Medical Faculty, Division for Specific Endocrinology, University of Düsseldorf, Düsseldorf, Germany
,
Michael Kanitz
2   Department of Medicine I, Molecular Thyroid Research Laboratory, Johannes Gutenberg University (JGU) Medical Center, Mainz, Germany
,
Derik Hermsen
3   Institute of Clinical Chemistry and Laboratory Diagnostics, Medical Faculty, University of Düsseldorf, Düsseldorf, Germany
,
Matthias Schott§
1   Medical Faculty, Division for Specific Endocrinology, University of Düsseldorf, Düsseldorf, Germany
,
George J. Kahaly§
2   Department of Medicine I, Molecular Thyroid Research Laboratory, Johannes Gutenberg University (JGU) Medical Center, Mainz, Germany
› Author Affiliations
Further Information

Publication History

received 15 March 2019

accepted 02 May 2019

Publication Date:
17 June 2019 (online)

Abstract

A rapid and fully automated chemiluminescent immunoassay for the detection of thyrotropin receptor autoantibodies (TSHR-Ab) based on a bridge technology was compared with two bioassays that measure either stimulating (TSAb) or blocking (TBAb) antibodies for the detection and differentiation of TSHR-Ab. A total of 229 patients with various thyroid disorders [151 with Graves’ disease (GD), 35 with Hashimoto’s thyroiditis (HT), 32 with nodular goiter, and 11 with thyroid cancer] were included. The bridge immunoassay was performed according to the manufacturer’s instructions (cut-off>0.55 IU/l). TSAb and TBAb were measured with reporter bioassays. Blocking activity was defined as percent inhibition of luciferase expression relative to induction with bovine TSH alone (cut-off>34% inhibition). TSAb was reported as percentage of specimen-to-reference ratio (> 140 SRR%). The 3 TSHR-Ab assays were negative in all patients with benign euthyroid nodular goiter and differentiated thyroid cancer. In contrast, in all patients with GD, irrespective of the disease duration, TSHR-Ab positivity was present in 127 of 151 (84%) and 140 (93%) for the bridge assay and TSAb bioassay, respectively (p<0.001). Fifteen of 151 (10%) GD samples were positive in the TSAb bioassay but negative in the bridge assay. The bridge assay and the TSAb bioassay correlated positively (r=0.39, p<0.0001) in patients with GD. Both assays detected TSHR-Ab in all ten untreated hyperthyroid patients with GD. In GD patients with a duration of less than six months, 27/29 (93%) and 28 (97%) were TSHR-Ab positive with the bridge and TSAb bioassay, respectively. In comparison, TSHR-Ab were present in two of 35 (6%) and five (14%) HT patients with the bridge and TSAb bio-assay, respectively. TSHR blocking antibodies were present in one (3%) patient with HT and in two (1%) patients with GD; these two GD patients were also bridge assay positive but TSAb bioassay negative. In conclusion, the bridge immunoassay and both bioassays are highly sensitive for the detection of TSHR-Ab. The bridge assay is, however, also positive in the presence of TSHR blocking antibodies detected in a TBAb bioassay.

* SA and TD share first authorship.


§ MS and GJK share senior authorship.