Levels of autoantibodies against human TSH receptor predict relapse of hyperthyroidism in Graves' disease.
ABSTRACT The aim of this study was to evaluate the ability of the more sensitive second-generation TSH receptor (TRAb) assay to predict recurrent Graves' disease (GD) vs. remission depending on TRAb levels. 93 patients with active GD were included in the study. By using a cut-off limit of 1.0 IU/l, all 93 patients were positive for TRAb (median: 4.6 IU/l) at the time of their first visit (single point measurement in median 5.1 months after initial diagnosis). Subsequently, 33 patients went into remission and were euthyroid during follow-up (median follow-up: 21.7 months), whereas 60 patients did not go into remission or developed relapse over the following 24 months. Median TRAb levels in the group of remission were significantly (p < 0.0001) lower than TRAb values in the relapse group (2.1 compared to 8.6 IU/l). Applying ROC plot analysis to compare different TRAb thresholds, a cut-off of 10 IU/l was established. Here, the specificity for relapse was 97 % as only 1 of 29 patients with TRAb values above 10 IU/l went into remission during follow-up, whereas all other 28 patients developed a relapse (positive predictive value for relapse: 96.4 %). In contrast, TRAb values lower than 10 IU/l had no impact on the prediction of remission. In conclusion, our data clearly indicate that TRAb measurement is useful for identifying patients that will not benefit from long-term antithyroid drug treatment.
Article: TSH receptor antibody measurements and prediction of remission in Graves' disease patients treated with minimum maintenance doses of antithyroid drugs.[show abstract] [hide abstract]
ABSTRACT: Prediction of remission is one of the main problems of antithyroid drug (ATD) therapy for Graves' disease especially in patients who are treated with a minimum maintenance dose of ATD. We evaluated the ability of new sensitive TSH receptor antibody (TRAb) assays to predict remission in Graves' patients using two commercially available kits (TRAb-CT from Cosmic Corporation and TRAb-Dyno from Yamasa Corporation), compared to the original PEG assay. When a euthyroid state was achieved for more than 6 months with methimazole 5 mg/day or propylthiouracil 50 mg/day and thereafter for three months with 5 mg every other day or 50 mg every other day, respectively, we discontinued ATD medication. One year of observation after discontinuation of ATD was completed in 71 patients (60 females, median age 43 years, range 18-71), and TRAb values from these patients were analyzed in relation to prognosis. Twenty-six (37%) of the 71 patients had relapse of thyrotoxicosis and 45 remained euthyroid. The median TRAb levels in the relapse group were significantly higher than those in the remission group (P < 0.05). Relapse occurred in 15/51 patients negative by TRAb-CT, in 11/20 patients positive by TRAb-CT (chi2 = 4.1; P < 0.05), in 11/42 patients negative by TRAb-Dyno and in 15/29 patients positive by TRAb-Dyno (chi2 = 4.8; P < 0.05). By contrast, relapse occurred in 23/64 patients with negative TRAb by PEG assay and in 3/7 patients with PEG assay positive values (n.s.). All patients with TRAb-CT values of 30% inhibition or greater, or TRAb-Dyno values of 3.0 U/L or greater relapsed during the observation period. Thus, measurement of TRAb by the new sensitive assays is useful for prediction of remission in our patients.Endocrine Journal 09/2006; 53(4):467-72. · 2.03 Impact Factor
Article: [TRAb determination in newly detected patients with hyperthyroidism and their prognostic importance].[show abstract] [hide abstract]
ABSTRACT: In more than 50 years since the first demonstration of the immune basis for thyroiditis was done, the autoimmune disease has been identified as a major cause of disfunction of all endocrine organs. Identification of the antithyroid with the radioreceptor assay is widespread in clinical use for differential diagnosis of other thyroid disorders manifesting with the hyperthyroidism. Our study included 44 patients with new onset Graves disease which was primarily verified according to the objective status of the patients (signs of hyperthyroidism), biochemical parameters (which included thyroid hormones) and detection of the TRAb (TSAb- thyreotropin-stimulating antibodies) at the beginning of diagnosis and in the first, second and after the third month since the introduction of antithyroid therapy (propiltiouracil). On the basis of the TSAb concentration level, we found that the response to the therapy was positive in 65.9% ("responders") of the patients and negative in 22.7% ("non responders") of the patients and without therapeutic effect were 11.4% of the patients. During the therapy (after the first month), in the group of non responders we found increased values of the TSAb (p<0.05) and in the group of responders we found reduction of the TSAb levels (p<0.05). Our study demonstrated that the therapy with propiltiouracil, after the first month divide patients with positive and negative response, which could change the therapeutic, options in the future.Medicinski pregled 62(7-8):304-7.