Inflammatory cytokine profiles in the tears of thyroid-associated ophthalmopathy

Abstract

To investigate the levels of seven inflammatory cytokines and one chemokine in tears of patients with thyroid-associated ophthalmopathy (TAO) and asymptomatic control subjects, and determine the correlations between tear inflammatory mediators and clinical parameters. Prospective observational cohort study. The study involved 21 patients with TAO and ten asymptomatic controls. TAO patients were divided into active TAO and inactive TAO on the basis of 7-point modified formulation of the clinical activity score (CAS). Ocular Surface Disease Index (OSDI) score, tear film break-up time (BUT) was obtained, and the Schirmer test and fluorescein staining were performed in all participants. Ten microliters of tears were collected for analysis the concentrations of interleukin (IL)-1β, IL-2, IL-6, IL-10, IL-17 interferon (IFN)-γ, tumor necrosis factor (TNF)-α and one chemokine (IL-8) by multiplex bead analysis. Fluorescein staining scores were higher, BUT scores were shorter, and Schirmer test scores were lower in patients with active TAO and inactive TAO than in control subjects. IL-1β, IL-6, and IL-8 concentrations in tears were significantly higher in active TAO than inactive TAO and the controls. TNF-α concentration was significantly higher in both active and inactive TAO compared with the controls. IL-17 was significantly higher in active TAO than the controls, and the level of IL-2 was significantly higher in inactive TAO compared with the controls. There were significantly positive correlations between tear IL-1β, IL-6 and IL-8 levels and CAS in TAO. No significant correlations were found between other cytokine concentrations and clinical parameters in TAO. The differences of tear inflammatory cytokines between patients with active and inactive TAO indicated that orbital inflammation may be involved in the ocular surface damage of TAO.