Increased Circulating Th17 but Decreased CD4+Foxp3+ Treg and CD19+CD1dhiCD5+ Breg Subsets in New-Onset Graves' Disease

Th17 and regulatory lymphocyte subsets such as Tregs and Bregs have been reported to play important roles in autoimmune diseases. The aim of this work was to perform quantitative studies of circulating Th17, Tregs, and Bregs in patients with new-onset Graves' disease (GD). Twenty GD patients and 20 healthy controls were involved in this study. Blood samples were taken for flow cytometry detection of CD4+IL-17+ Th17, CD4+Foxp3+ Tregs, and CD19+CD1dhiCD5+ Bregs and meanwhile, for real-time PCR measurement of gene expressions of RORγt, IL-17 and IL-10. The proportions of Tregs and Bregs as well as the Foxp3 gene expression but not IL-10 were significantly decreased in GD group compared with the healthy controls. The frequency of Th17 together with the gene expressions of RORγt and IL-17 were significantly increased in the GD group. Furthermore, the Th17/Treg ratio was also significantly higher in GD group. A significant positive correlation between Th17 and TSAb (r = 0.656, p < 0.001) but significant negative correlations between Treg/Breg and TSAb (r = -0.339, p = 0.032; r = -0.759, p < 0.001) were identified among the participants. This study indicated that increased Th17 and impaired Treg responses, along with a decreased number of CD19+CD1dhiCD5+ Breg cells, were involved in GD pathogenesis.