Endocrine Abstracts

Up till now, altered balance of Th1 and Th2 immune cells has been postulated to play an important role in the pathogenesis of autoimmune thyroid diseases (AITD). However, recent studies on thyroid diseases suggest a new role for Th17 (T helper 17) cells that have been classified as a new lineage, distinct from Th1, Th2 and Treg cells. Despite wide interest, role of Th17 cells in the pathogenesis of inflammatory and autoimmune diseases is still debated. Th17 cells are involved in immune responses against extracellular pathogens and have the ability to secrete cytokines: IL17, IL17F, IL22 and IL21. Th17 cells can be characetrized by several surface markers, i.e. CCR6 (CD196), IL23R, IL12Rβ2 and CD161.

The aim of the study was to estimate the frequencies of circulating CD4⁺CD161⁺CD196⁺ and CD4⁺IL17⁺ Th17 cells in patients with Graves’ disease (GD), Hashimoto’s thyroiditis (HT) and in healthy controls.

Polychromatic flow cytometry and several fluorochrome-conjugated monoclonal antibodies were applied to delineate Th17 cells with either CD4⁺CD161⁺CD196⁺ or CD4⁺IL17⁺ phenotype.

In untreated patients with AITD we observed a tendency to increased frequencies of CD4⁺CD161⁺ CD196⁺ and CD4⁺IL17⁺ Th17 lymphocytes in comparison to the healthy controls. In cases with HT, positive correlation between percentage of CD4⁺CD161⁺CD196⁺T cells and serum level of anti-TPO antibodies was detected.

We conclude that the increase percentage of Th17 cells in children with Graves’ disease and Hashimoto’s thyroiditis can suggest their role in initiation and development of immune processes in AITD.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.