EFFECTS OF HELPER AND REGULATORY CELLS UPON PHENOTYPIC COMPOSITION OF BLOOD B LYMPHOCYTES AND THYROID GLAND IN GRAVES’ DISEASE

The aim of this work was a comparative study of the helper- (Th cells) and regulatory T cells (Treg) effects upon the phenotypic composition of B lymphocytes in blood and thyroid tissue in Graves’ disease (GD). 43 women with GD were examined. The diagnosis of GD was based on clinical and laboratory signs of the disease: complaints, clinical picture of the thyrotoxicosis with objective examination, characteristic sonographic changes in thyroid gland, as well as elevated titers of antibodies to thyroid-stimulating hormone receptor in blood serum, and corresponding changes in thyroid status. 67 practically healthy women were examined as a control. The studies of Th cells, Treg and B lymphocytes phenotypes in blood and thyroid tissue were carried out by flow cytometry using direct immunofluorescence, respectively, in whole peripheral blood and lymphocytes isolated from thyroid tissue. The relative amounts of Tregs in thyroid gland from the patients with GD corresponds to their level in the blood. We did not find any changes in the content of blood T helpers expressing vs. non-expressing CD25 receptors, as compared to the control values. In patients with GD, an increased B1 cells content was revealed in peripheral blood. The percentage of this B cell subpopulation in thyroid tissue is reduced when compared to the levels found in blood, but with increased memory B cells contents. The number of activated B lymphocytes (by CD23 marker) in blood of patients with GD is reduced when compared to control values. It was found that, in thyroid tissue, there is an even more pronounced decrease in the relative amount of activated B cells compared to the levels detected in blood from these patients. By means of correlation analysis, it was found that increase in activated B lymphocytes in blood from controls is accompanied by a co-directional reaction from Treg (the usual immunoregulatory process). In Graves’ disease, such a relationship was not found. The amounts of Treg and activated T helper cells in blood of the patients did positively correlate with common B lymphocytes, B2 cells and na ve B lymphocytes. Meanwhile, Treg’s in thyroid tissue, were completely excluded from the system of interactions with activated B lymphocytes. It is assumed that a decrease in Treg’s content in peripheral blood, along with altered functional activity is observed in patients with GD