Purpose: The study aimed to evaluate cytokines in tears as potential biomarkers in non-infectious uveitis.
Methods: Tear samples were obtained using Schirmer strips from 50 patients enrolled in a randomised controlled study of simvastatin in non-infectious uveitis and from a control group of 30 healthy participants. The concentrations of IL-6, IL-8, IL-10, and IFN-γ in tears were measured at the study's baseline and again after 8 weeks of treatment using commercial enzyme-linked immunosorbent assay kits.
Results: The concentrations of tears IL-6 and IL-10 were increased in patients with non-infectious uveitis in comparison with the healthy participants. Longer disease duration was associated with elevated levels of IL-6. The concentrations of the studied cytokines in tears did not correlate with the extent of eye inflammation at baseline. No link between the changes in cytokine levels and changes in clinical parameters during treatment was observed. Baseline IL-10 concentrations independently predicted the development of the clinical response to treatment at weeks 4 and 8.
Conclusion: Although elevated in non-infectious uveitis patients, tear cytokine levels do not correlate with eye inflammation and are not sensitive to change after treatment. However, the level of IL-10 may be a predictive biomarker of response to the treatment of uveitis.
Trial registration: NCT04183387.
Keywords: Autoimmune; Cytokines; Hydroxymethylglutaryl-CoA reductase inhibitors; Non-infectious; Statins; Tears; Uveitis.