LAUSR

PD-1 maintains tolerance and inhibits autoimmune responses. Graves' disease (GD) is one of the most frequent autoimmune diseases of unclear etiology. The aim of this study was to evaluate the percentage and absolute counts of PD-1 positive T and B cells in newly diagnosed, untreated patients with hyperthyroidism due to GD. The study group included 30 patients and the control group comprised of 20 age- and sex-matched healthy individuals. Results showed significantly higher frequencies and absolute counts of PD-1 positive CD3+CD4+ T cells, CD3+CD8+ T cells and CD19+B cells in patients with GD in comparison to the healthy volunteers. Moreover, higher mean fluorescence intensity of PD-1 was found on CD3+CD4+ T cells, CD3+CD8+ T cells and CD19+B cells in the study group than in the control group. These results suggest that PD-1 protein might involved in the pathogenesis of GD.