ESPE Abstracts

Background: The basic subset of T cells playing a major role in the pathogenesis of Hashimoto’s thyroiditis are CD8+T cells. The mechanism of disease initiation is dysfunction of natural Tregs leading to breakdown of the self-tolerance. The best known subset of natural Tregs are CD4+Foxp3+T, but CD8+T cells expressing CD122 were also recognized as functional Treg cells.

Objective and hypotheses: The aimof the study was to evaluate the contribution of CD8+CD122+T cells in the whole amount of CD8+T cells in children with autoimmune thyroiditis.

Method: 59 children were examined: 35 with chronic autoimmune thyroiditis type Hashimoto (AIT), mean age 11.37±3.6 years; range: 4.5–17.5 years and 24 healthy children as controls. PBMCs were stained with MABs according to manufacturer instructions (Becton Dickinson): anti-CD8 FITC, anti-CD122 PE and isotypic controls were included. The samples were evaluated using flow cytometer FACS Canto II (Becton Dickinson). The results were presented as percentage of CD8+, CD8^bright, and CD8^dim expressed CD122 antigen. TSH, thyroid hormones, and thyroid antibodies were evaluated by MEIA, Abbott. Statistical analysis was performed using Mann–Whitney U test and the correlation tests.

Results: In children with AIT the percentage of CD8+CD122+ was significantly higher than in control group, especially in the CD8^dim CD122+ subset. In children with AIT any significant correlations between the subsets of CD8+CD122+T cells and hormonal or antibodies status were not found.

Conclusion: In children with AIT is observed an increased contribution of CD8^dimCD122+T cells in the whole amount of CD8+T cells subset.