One-tube-PCR technique for CCL2, CCL3, CCL4 and CCL5 applied to fine needle aspiration biopsies shows different profiles in autoimmune and non-autoimmune thyroid disorders

Autoimmune thyroid diseases are characterized by lymphocytic infiltration of the thyroid gland. Chemokines are crucial in the recruitment of lymphocytes and might play an important role in the pathogenesis of autoimmune thyroid disease. The aim of this study was to test the feasibility of analysing by one-tube reverse-transcriptase polymerase chain reaction (RT-PCR) technique CC chemokine profiles in samples obtained by fine needle aspiration biopsy (FNAB). In 27 out of 35 (77%) samples, the material was sufficient for analysis and in 16 (59%) chemokines were detected, thus demonstrating the potential of this technique. Moreover, even in this small group, a statistically significant increase of CCL3 and CCL4 was found in samples from patients with autoimmune thyroid disease as compared to those with multinodular goiter. Chemokine profile measured by improved multiamplification techniques in FNAB thyroid samples may become a useful complementary tool for the management of thyroid autoimmune disease as it constitutes a source of data for research of their pathogenesis.

Transcription of a broad range of self-antigens in human thymus suggests a role for central mechanisms in tolerance toward peripheral antigens

The role of the thymus in the induction of tolerance to peripheral antigens is not yet well defined. One impending question involves how the thymus can acquire the diversity of peripheral nonthymic self-Ags for the process of negative selection. To investigate whether peripheral Ags are synthesized in the thymus itself, we have determined the expression of a panel of circulating and cell-bound peripheral Ags, some of which are targets of autoimmune diseases, at the mRNA level in total thymic tissue and in its main cellular fractions. Normalized and calibrated RT-PCR experiments demonstrated the presence of transcripts of nonthymic self-Ags in human thymi from 8 days to 13-yr-old donors. Out of 12 glands, albumin transcripts were found in 12; insulin, glucagon, thyroid peroxidase, and glutamic acid decarboxylase (GAD)-67 in six, thyroglobulin in five, myelin basic protein and retinal S Ag in three, and GAD-65 in one. The levels of peripheral Ag transcripts detected were age-related but also showed marked interindividual differences. Cytokeratin-positive stromal epithelial cells, which are a likely cellular source for these, contained up to 200 transcript copies of the most expressed peripheral Ags per cell. These results implicate the human thymus in the expression of wide representation of peripheral self-Ags and support the view that the thymus is involved in the establishment of tolerance to peripheral Ags. The existence of such central mechanism of tolerance is crucial for the understanding of organ-specific autoimmune diseases.