ESPE Abstracts

Background: Almost all cases of hyperthyroidism in children result from Graves’ disease (GD). Recent studies have confirmed a significant role of T cells in the development of autoimmune diseases. However, the interactions between NKT-like cells and NK cells in GD are still poorly understood.

Objective and hypotheses: The aim of the study was to assess the frequencies of peripheral blood T, NK and NKT-like cells in children with GD.

Method: We studied 50 GD and 20 age- and sex-matched healthy children. Percentages of NK and NKT-like cells were evaluated with flow cytometry using monoclonal antibodies: anti-CD3/FITC, CD16CD56/PE, CD45/PerCP (BD Biosciences), which allowed for simultaneous assessment of CD3⁺T lymphocytes and NK (CD16⁺CD56⁺) cells. During analysis, the CD3⁺CD16⁺CD56⁺ population was also determined. Immunofluorescence studies on T cell subsets were performed using a combination of the following mAbs: CD3/FITC, CD19/PE, CD8/FITC, CD4/PE, purchased from R&D Systems. Statistical analysis of the results was conducted using Statistica 9.0. A value p less than 0.05 was considered statistically significant.

Results: The mean frequency of CD3+CD56+CD16+ NKT-like cells in the peripheral blood of children with GD was 10.93%±11.02% and this value was significantly lower in comparison to the control group (21.15%±9.08%, P=0.0005). The mean percentage of CD56+CD16+ NK cells in the group of patients was 14.67%±6.89%, and was significantly higher compared to the healthy controls (4.71%±2.99%, P=0.000002). The mean percentage of CD3+T lymphocytes in the peripheral blood of children with GD was 67.91%±16.56% and was significantly higher in comparison to the control group (51.7%±24.12%, P=0.02). The mean percentage of CD8+T lymphocytes in the study group was 28.89%±11.68% and was significantly higher in comparison to the healthy controls (18.72%±6.86%, P=0.001).

Conclusion: Our findings of the abnormalities in immune cells distribution in peripheral blood of GD children suggest that GD development and progression is related to the dysregulation of the immune system.