Endocrine Abstracts

Graves’ disease (GD) has been recognised for more than 100 years, its pathophysiological mechanisms are incompletely understood.

Aim: To investigate the helper- (Th-cells) and regulatory T-cells (Treg) influence on B-lymphocytes phenotypic composition of blood and thyroid tissue in GD.

Materials and methods: The study included 43 women with GD, mean age 39.95±14.38, who were performed the epifascial thyroidectomy and 67 healthy women were examined as a control. The median of thyroid stimulating hormone, autoantibodies to TSH receptor, free thyroxine and triiodothyronine level was respectively 0.08 (0.01; 0.58 mIU/l, 10.25 (6.85; 24.68) IU/ml, 16.89 (11.39; 31.5) and 5.93 (4.6; 7.7) nmol/ml. Phenotypic composition of Th-cells, Treg and B-lymphocytes were measured by flow cytometry, using direct immunofluorescence, respectively, of whole peripheral blood and lymphocytes isolated from thyroid tissue.

Results: In patients with GD in peripheral blood increased the level of B1-cells. In thyroid tissue of GD patients we observed high level of memory B-cells, but decreasing the relative number of B1-cells, in contrast to its level in peripheral blood (P<0.001). In healthy control increasing the content of activated B-lymphocytes in the blood accompanied by a co-directional reaction from Treg, but in patients with GD such mechanism is disrupted. In peripheral blood of GD patients we revealed the positively interaction between the relative amount of B-lymphocytes with Treg and activated T-helper cells (r=+0.39, P=0.009), B2-cells and naïve B-lymphocytes with CD3⁺CD4⁺CD25⁺- (r=+0.49, P<0.001 and r=+0.42, P=0.003, respectively) and CD3⁺CD4⁺CD127^LowCD25^High-cells (r=+0.49, P<0.001 and r=0.37, P=0.012, respectively). In thyroid tissue of GD patients the relative number of CD3⁺CD4⁺-cells interact with the level of CD19⁺CD5⁺CD23⁺-lymphocytes (r=+0.79, P=0.036) and the percentage number of CD3⁺CD4⁺CD25⁺-cells with CD19⁺CD23⁺- (r=+0.85,P=0.014), CD19⁺CD5^-CD23⁺- (r=0.80,P=0.034), CD19⁺CD5⁺CD23⁺- (r=+0.93, P=0.025) and CD19⁺CD27⁺CD23⁺-lymphocytes (r=+0.82, P=0.023).

Conclusion: It is assumed that in patients with GD and thyrotoxicosis decreased not only the content of Treg in peripheral blood, but also a violation of their functional activity. In patients with GD the ac ivated B lymphocytes and Treg does not involve in correlation system, respectively, in peripheral blood and thyroid tissue.