The expression of interleukin-15 and interleukin-17 in tears and orbital tissues of Graves ophthalmopathy patients

Objective The objective of this study was to study the levels of interleukin (IL)-15 and IL-17 in tears and orbital tissues of the patients with the Graves ophthalmopathy (GO) (active and inactive stages) and in controls. Methods Twenty-four active GO patients (CAS >= 3/7) were collected in our research. All patients were treated with corticosteroids during the therapy process (4-15 months) and developed into the inactive phase (CAS <= 2/7). The tear samples were gathered from inactive and active stages of patients with GO and sex-matched and age-matched controls (volunteers, n = 24) for the enzyme-linked immunosorbent assay measurement of IL-15 and IL-17. The orbital tissues were collected from inactive stage of patients with GO and healthy volunteers for the analysis of IL-15 and IL-17 positive cells using the immunohistochemical analysis. Results In comparison with the volunteers, significant upregulation of IL-15 and IL-17 were identified in tears of active (P < 0.05) and inactive patients with GO (P < 0.01). Compared with inactive patients with GO, the levels of IL-15 and IL-17 in the tears were obviously higher than those in the active patients with GO. In addition, higher expression of IL-15 and IL-17 positive cells were found in the orbital organization of inactive patients with GO compared with volunteers. Conclusion The differences in IL-15 and IL-17 expression between GO patients (active and inactive stages) and controls suggested both IL-15 and IL-17 expression were significantly correlated with thyroid-associated ophthalmopathy pathogenesis and development.