Inflammatory cytokine profiles in the tears of thyroid-associated ophthalmopathy

Abstract

Purpose: 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.

Methods: 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.

Results: 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.

Conclusions: 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.