Th1/Th2 Cytokines in Patients with Graves' Disease with or without Ophthalmopathy

About 25-50% of Graves' disease (GD) patients develop thyroid eye diseases, which is associated with inflammatory process and abnormalities in the levels of several cytokines in orbital tissues in GD. The aim of this study was to determine the Th1 and Th2 serum cytokines in patients with GD with or without ophthalmopathy. Serum levels of cytokines and autoantibodies including Interferon-gamma (IFN-gamma), Interleukin-2 (IL-2), Interleukin-4 (IL-4), Interleukin-10 (IL-10), TSH receptor autoantibody (TRAb), thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody(TgAb) were measured by enzyme linked immunosorbent assay(ELISA) in 34 patients with GD and in 33 normal controls. Patients were also divided in two subgroups: 18 cases with ophthalmopathy and 16 cases without ophthalmopathy. Cytokine and antibody responses were analyzed in both groups. Compared with control subjects, patients with GD showed elevated levels of IL-2 and IL-10. IFN-gamma levels were lower in patients in comparison to the controls. No significant differences were found between patients and controls regarding the IL-4. There was no statistically significant difference in cytokine levels between those with or without ophthalmopathy. Quantitative-cytokine analysis demonstrated that a combination of Th1 and Th2 cytokines may contribute to the pathogenesis of GD. These results also indicate that IL-10, but not IL-4, is related to the moderate and severe forms of thyroid associated ophthalmophathy.