Abstract: Objective To explore the role of CD4+CD25+Foxp3+Treg/CD4+IL-17A+Th17 cells and the related cytokines in Graves’
ophthalmopathy. Methods Based on clinical activity scores (CAS), we divided patients with untreated Graves’ ophthalmopathy
into active group (AGO group with CAS≥3 (15 cases) and non-active group (NGO group) with CAS<3 (15 cases),
with another 15 patients with untreated Graves’ disease free of eye symptoms (GD group) and 15 normal subjects as controls.
Peripheral venous blood Treg/Th17 cell ratio was determined using flow cytometry. RT-PCR was used to detect the mRNA
expression levels of Treg-specific transcription factor Foxp3 and Th17-specific transcription factor RORγt. Enzyme-linked
immunosorbent assay (ELISA) was used to detect the serum levels of Th17 cell-related cytokines (IL-17A, IL-23, and IL-6) and
Treg-related cytokines (TGF-β, IL-10, and IL-35). Results Compared with the normal subjects, the patients in GD, NGO, AGO
groups all showed significantly increased Th17 cell count (P<0.05), which was the highest in AGO group. RT-PCR results
revealed significantly increased RORγt in GD, NGO, and AGO groups, also the highest in AGO group. Serum IL-17A, IL-23,
and IL-6 levels all showed significant increments in GD, NGO, and AGO groups (P<0.05), especially in AGO group. Among the
Treg-related cytokines, TGF-β and IL-35 levels decreased (P<0.05) but IL-10 increased significantly (P<0.05) in GD, NGO, AGO
groups. Conclusion Decreased immunosuppressive capacity of Treg cells can be an important factor in the pathogenesis of
Graves’ ophthalmopathy. Th17 cells may also participate in the occurrence and progression of Graves’ ophthalmopathy and
can serve along with related cytokines as novel indicators of the disease activity. Impaired Treg/Th17 balance may importantly
contribute to the occurrence of Graves’ ophthalmopathy.