Increased serum interleukin-17 in Graves' ophthalmopathy.

Background: Interleukin (IL)-17 and T helper 17 (Th17) cells are reported to be involved in many autoimmune diseases. The aim of this study is to investigate the involvement of IL-17 in the pathogenesis and disease activity of Graves' ophthalmopathy (GO).

Methods: Sixty-two GO patients and 19 healthy controls were recruited. Serum concentrations of cytokines, IL-17, IL-6, IL-23, and IL-16, were measured using multiplexed microsphere-based flow cytometric immunoassays. GO hormonal parameters, clinical activity score (CAS), exophthalmometry, and extraocular muscle involvement were evaluated, and relationships with cytokine concentrations were analyzed.

Results: The concentration and positive detection rates of serum IL-17 were significantly higher in patients with GO than in controls. The serum levels of IL-17 in active GO patients were higher than that of inactive GO patients. Serum IL-17 concentration had significant correlation with CAS (p < 0.001).

Conclusion: The increased serum level of IL-17 and related cytokines in GO patients and the correlation of IL-17 concentration with the clinical activity scores suggest that IL-17 may play a pathophysiological role in GO.