Protein-A purified human immunoglobulins: a comparison of thyroid stimulating and thyrotrophin receptor binding activities in thyrotoxicosis.
AffiliationDepartments of Chemical Pathology, University of Manchester, Clinical Sciences Building, Hope Hospital, Eccles Old Road, Salford M6 8HD
MetadataShow full item record
AbstractProtein-A purified human thyroid stimulating immunoglobulins (TSIg) and thyrotrophin binding inhibiting immunoglobulins (TBIIg) were measured in euthyroid subjects and thyrotoxic patients by bioassay and TSH radioligand receptor assay respectively. Unextracted sera from euthyroid and thyrotoxic subjects inhibited both basal and TSH stimulated iodide uptake in the bioassay, which was based on iodide uptake in porcine thyrocytes. Similar effects were seen with Ig and TSIg extracted from sera using either polyethylene glycol or ammonium sulphate. However IgG and TSIg prepared using Protein-A Sepharose CL-4B from sera of euthyroid subjects had little effect in this system. The majority of Protein-A purified TSIg preparations from sera of thyrotoxic patients stimulated iodide uptake in procine thyrocytes in a dose-dependent manner and most (85%) diluted parallel to both bovine and human TSH. TSIg and TBIIg from 73 patients with thyrotoxicosis were assessed using the bioassay and receptor assay and compared to a control group of 35 euthyroid subjects. The median (and range) values for TSIg and TBIIg in the euthyroid group were 4.35 (0.8 to 7.5, % stimulation over control) and 2.7 (-9.3 to 8.6, TBII index) for the bioassay and radioreceptor assay respectively. A value of greater than 10.0 in both assays was taken as a positive result. Of the thyrotoxic patients 61 out of 73 were positive in the bioassay (83.6%) compared to 60 in the radioreceptor assay (82.2%). There was a positive correlation between the two assays (r = 0.821, P less than 0.001). Of the 73 thyrotoxic patients 40 were untreated, 18 had received carbimazole and 15 had been previously treated with iodine-131. TSIg levels in the untreated thyrotoxics were similar to those in either group of treated patients. However they were higher (P less than 0.05) in the iodine-131 group than in the patients treated with carbimazole. Similar results were obtained for TBIIg. The coupling of a specific extraction method for human serum IgG with a bioassay for TSIg has demonstrated a high prevalence of these immunoglobulins in patients with thyrotoxicosis. The agreement between this assay and a radioreceptor assay was good, indicating that TSH displacing and thyroid stimulating activities of these immunoglobulins are closely related.
CitationProtein-A purified human immunoglobulins: a comparison of thyroid stimulating and thyrotrophin receptor binding activities in thyrotoxicosis. 1986, 25 (4):441-51 Clin Endocrinol
- Clinical utility of thyrotropin-receptor antibody assays: comparison of radioreceptor and bioassay methods.
- Authors: Morris JC 3rd, Hay ID, Nelson RE, Jiang NS
- Issue date: 1988 Jul
- Comparative evaluation of cyclic AMP and iodide accumulation responses to thyroid-stimulating immunoglobulins in cultured FRTL-5 cells.
- Authors: Bidey SP, Ekins RP
- Issue date: 1986 Apr
- Immunoglobulins of untreated Graves' patients with or without thyrotropin receptor antibody (determined by porcine thyrocytes) universally elicit potent thyroid hormone-releasing activity in cultured human thyroid follicles.
- Authors: Sato K, Yamazaki K, Yamada E, Kanaji Y, Miura M, Obara T
- Issue date: 1999 Oct
- Comparison of human and porcine thyroid membranes for radioreceptor assay of bovine thyrotrophin and thyrotrophin-binding inhibiting immunoglobulins.
- Authors: Humphries H, Dirmikis SM, Munro DS
- Issue date: 1982 Jun
- Characterization of thyroid-stimulating blocking antibodies that appeared during transient hypothyroidism after radioactive iodine therapy.
- Authors: Kung AW, Lau KS, Kohn LD
- Issue date: 2000 Oct