Interleukin-6 levels in the conjunctival epithelium of patients with dry eye disease treated with cyclosporine ophthalmic emulsion

Purpose. To evaluate interleukin-6 (IL-6) levels in the conjunctival epithe lium of patients with moderate to severe dry eye disease before and after t reatment with cyclosporin A ophthalmic emulsion (CsA) or its vehicle. Metho ds. Conjunctival cytology specimens were obtained from a subset of patients enrolled in a 6-month randomized, double-masked clinical trial of the effi cacy and safety of topical CsA at baseline and after 3 and 6 months of B.I. D. treatment with 0.05% cyclosporine emulsion (n = 13), 0.1% cyclosporine e mulsion (n = 8), or vehicle (n = 10). RNA was extracted and a competitive r everse transcriptase polymerase chain reaction (RT-PCR) was used to evaluat e the levels of mRNA encoding the inflammatory cytokine IL-6 and a housekee ping gene, G3PDH. Levels of IL-6 and G3PDH were measured and compared. Resu lts. There was no change from baseline in the level of G3PDH after 3 or 6 m onths in any group. IL-6 normalized for G3PDH (IL-6/G3FDH ratio) was not di fferent from baseline at 3 months but showed a significant decrease from ba seline in the group treated with 0.05% CsA (p = 0.048) at 6 months. No sign ificant between-group differences were noted and no correlation was observe d between the change in IL-6/G3PDH and corneal fluorescein staining. Conclu sions. This preliminary, small-cohort study showed a decrease in IL-6 in th e conjunctival epithelium of moderate to severe dry eye patients treated wi th 0.05% CsA for 6 months. The observed decrease suggests that dry eye dise ase involves immune-mediated inflammatory processes that may be decreased b y treatment with topical ophthalmic cyclosporine.