Immunological impression cytology of the conjunctival epithelium in patients with thyroid orbitopathy-related dry eye

Abstract

Thyroid orbitopathy (TO) is an autoimmune disease that is complicated by ocular surface disorders, leading to discomfort. Dry eye is very prevalent in patients with TO. Recent studies on the pathogenesis of dry eye have focused on the inflammatory process, and some supporting evidence has been discovered. Because TO is a disorder of autoimmune origin, we assumed that the association between TO and dry eye is related to inflammation. Inflammation of the ocular surface in TO-related dry eye has not been well studied. In this study, we assessed cellular inflammation of the ocular surface and the cytokine profiles in patients with TO-related dry eye. Conjunctival impression cytology (CIC) was assessed with an immunofluorescent assay. TO-related dry eye was diagnosed by using the Schirmer test, tear break-up time, thyroid function, and clinical signs. CIC was combined with immunological staining of interleukin-1a (IL-1a), IL-1b, and IL- 6. The immunological impression cytology (IC) grade was compared to the clinical activity score of TO. All TO patients with dry eye were positive for IL-1a, IL-1b, and IL-6. However, the normal controls were also positive for IL-1a. A trend was observed between the clinical inflammatory score and immunological IC grade. This study was the first to delineate the immunological IC of TO-related dry eye. Our study aimed to investigate the pathogenesis of dry eye in TO. Our findings suggest that the conjunctival cytokines IL-1a, IL-1b, and IL-6 may play a role. The results of this study will be useful for future studies of additional inflammatory cytokines, and the levels of these cytokines could be used as an outcome to assess the efficacy of treatment, such as anti-cytokine or immunosuppression therapy, in patients with TO-related dry eye or other ocular surface inflammatory disorders.