Comparison of a solid phase human- versus porcine- thyrotropin receptor-based immunoassay for the measurement of thyrotropin receptor antibodies in patients with thyroid diseases.

Thyrotropin receptor (TSHR) antibody (TRAb) assays based on human or porcine TSHR which are coated to a solid phase are the most commonly used detection methods in clinical practice for patients with thyroid diseases. Yet the difference of the diagnostic values of the two TRAb assays is largely unclear. The aim of our present study was to evaluate the clinical perfomance of a solid phase porcine TRAb assay based on an ELISA technique (TRAb-porcine) and a human TRAb assay based on a chemiluminescence signal detection procedure (TRAb-human). Of 158 patients enrolled in the study, 84 suffered from Graves' disease (GD), 34 had Hashimoto's thyroiditis (HT) and 40 had euthyroid nodular thyroid disease (NTD) without signs of autoimmunity. TRAb measurements were performed according to the manufacturer's instructions. The mean values of TRAb titers detected by the TRAb-human and TRAb-porcine assays in patients with GD were 12.14+/-10.80 IU/L and 15.27+/-13.65 IU/L, respectively. TRAb were detected in 80 and 78 out of 84 GD patients by the TRAb-human and TRAb-porcine assay, respectively. The diagnostic sensitivity of the TRAb-human and TRAb-porcine immunoassay was 95.2 and 92.9% respectively, by 100% specificity of both methods. TRAb values in GD patients detected by the TRAb-human and TRAb-porcine assays were significantly correlated (r=0.929, p<0.0001). Our results indicate that the second generation TRAb-porcine assay based on solid phase technology had a slightly lower diagnostic sensitivity compared to the TRAb-human assay.

Comparison of M22-based ELISA and human-TSH-receptor-based luminescence assay for the measurement of thyrotropin receptor antibodies in patients with thyroid diseases.

Previously, a new procedure for measuring serum TSH receptor autoantibodies (TRAb) was reported in which the autoantibodies inhibit binding of a human monoclonal thyroid stimulating antibody M22 to TSHR-coated ELISA plate wells (TRAb ELISA). The aim of the present study was to evaluate the clinical performance of this assay in comparison to the second generation TRAb assay (TRAb LIA) based on the recombinant human TSH-receptor and chemiluminescence technology (TRAb LIA). Among the 158 patients, 84 patients suffered from Graves' disease (GD), 34 patients had Hashimoto's thyroiditis (HT), and 40 patients had euthyroid nodular thyroid disease (NTD) without signs of autoimmunity. TRAb measurements were performed according to the manufacturer's instructions. Out of 84 GD patients, 80 (95.2%) were TRAb positive as detected by the TRAb LIA. One GD patient had TRAb values within the grey zone (1.0-1.5 IU/l). All patients with HT and NTD were negative except in 6 (8.1%) cases whose TRAb values were within the grey zone. On the basis of the recommended cutoff value (TRAb 1.0 IU/l), the TRAb ELISA found 78 of 84 (92.9%) GD patients to be TRAb positive. None of the patients with HT, but two cases (5.0%) with NTD were TRAb positive. The diagnostic sensitivity of the TRAb LIA and TRAb ELISA assays was 95.2 and 92.9%, while the specificity was 100% and 97.3%, respectively. There was a close correlation (r=0.968, p<0.0001) between both assays in 84 patients with GD. Additionally, the between-run imprecision close to the cutoff limit was assessed. The calculated between-run coefficient of variation (CV) of the TRAb ELISA was 28.2% at the recommended cutoff value of 1.0 IU/l. Due to the evaluated imprecision data we propose a higher cutoff value correlating with a between-run CV of 20% (functional assay sensitivity). Our results indicate that due to a worse imprecision the TRAb ELISA has a slightly lower sensitivity and specificity compared to the TRAb LIA assay. These findings suggest that the M22 monoclonal antibody-based TRAb ELISA is not as reliable as other second generation TRAb assays in the diagnosis of Graves' diseases.

Circulating chemokines in patients with autoimmune thyroid diseases.

Chemokines are a group of small proteins that recruit different leukocyte subtypes to sites of inflammation and play important roles in initiating and maintaining immunological responses in autoimmune endocrine diseases including Graves' disease (GD) and Hashimoto's thyroiditis (HT). Previous studies have found increased gene and protein expression of different kinds of chemokines not only within the thyroid gland but also within thyroid cells in GD or HT patients. A few studies have determined serum levels of chemokines, with conflicting results. We measured circulating concentrations of CCL2, CCL5, CXCL9, and CXCL10 in patients with GD, HT, and nontoxic nodular thyroid disease (NNT). While CCL2 and CXCL9 concentrations were comparable in patients with either AITD or NNT, CCL5 was significantly increased in GD patients compared with HT or NNT subjects. In contrast, CXCL10 levels were lower in patients with GD, but the difference was statistically significant only when compared with patients with HT (p=0.0018). Importantly, GD patients who relapsed or went into remission had significantly different levels of CXCL9 (p=0.0252). Serum levels of CCL2, CCL5, CXCL9, and CXCL10 did not reveal any correlation with thyroid volume; with the levels of thyrotropin (TSH), FT3, or FT4; or with the titers of TSH receptor antibody and thyroperoxidase antibody. These data suggest that the expression patterns of chemokines in various thyroid diseases differ from each other, which may reflect the distinct immune responses in HT and GD.

Chemokines and autoimmune thyroid diseases.

Chemokines are a family of small, structurally related molecules that regulate cell trafficking of various types of leukocytes through interactions with their seven-transmembrane, G protein-coupled receptors. Their major function is the recruitment of leukocytes to inflammation sites, but they also play roles in tumor growth, angiogenesis, organ sclerosis, and autoimmunity. A variety of evidence has accumulated to support the concept that thyroid follicular cells as well as intrathyroidal lymphocytes are able to produce CC and CXC chemokines, which, in turn, promote the initiation and maintenance of an inflammatory process resulting in autoimmune thyroid diseases (AITD). Overexpression of several chemokines in AITD has been demonstrated. Moreover, alterations of CCL2, CCL5, CXCL9, and CXCL10 have been shown in circulation of many patients with AITD. In subjects with Graves' disease, antithyroid drug treatment, radioactive iodine ablation, and thyroidectomy can significantly reduce CXCL10 levels. The measurement of chemokines in serum of AITD patients might provide a useful parameter for the evaluation and prediction of disease activity and progression. Further experimental and clinical studies will expand our understanding of the clinical implications of chemokine detection and the effects of chemokines on the pathogenesis of AITD.

Dendritic cell vaccination induces tumor epitope-specific Th1 immune response in medullary thyroid carcinoma.

The existence of inherited aggressive forms of medullary thyroid carcinoma (MTC) and their resistance to classical therapies make it a prime candidate for adoptive immunotherapy. Highly potent antigen-presenting cells, namely dendritic cells (DCs), may serve as an interesting tool for anticancer vaccination. Here we report on the IN VITRO findings of a vaccination trial in five MTC patients, who were treated with a new DC generation protocol consisting of granulocyte-macrophage colony-stimulating factor and interferon-alpha (IFN-DCs). These cells were pulsed with tumor-specific calcitonin and administered twice. In two patients who responded to therapy we found a large increase (in mean 2.9+/-1.9%) of antigen-specific IFN-gamma-secreting CD4+ cells as well as an increase of granzyme B positive CD8+ cells (mean 2.2+/-0.2%) in the peripheral blood. In parallel, a decrease of CD4+/CD25+/FoxP3+ regulatory T cells was seen. Importantly, IN VITRO stimulation of PBMC with 10 different 15mer calcitonin peptides resulted in the identification of two HLA class II epitope regions within the central part of full-length calcitonin. These data were in accordance with the results drawn from the computer-based algorithm epitope prediction software SYFPEITHI. Measurement of different pro- and anti-angiogenic factors did not allow for a distinct outcome of prediction of the treated patients. In summary, we have demonstrated that immunization with IFN-DCs leads to a tumor epitope-specific immune response in MTC patients and may, therefore, represent a promising tool for future vaccination trials.