Serum Cytokines As Biomarkers for Age-related Macular Degeneration

Purpose: This study evaluates the potential of serum pro-inflammatory cytokines as AMD biomarkers.

Methods: Serum samples from 30 age-related macular degeneration (AMD) patients and 15 age-matched controls were examined for 16 inflammatory cytokines using multiplex ELISA. Patients were divided into three subgroups (improvement/no change/deterioration during anti-VEGF treatment) by OCT and funduscopy, and correlated to the cytokine levels.

Results: Serum concentrations of IL-1α, IL-1β, IL-4, IL-5, IL-10, IL-13, and IL-17 were significantly higher in AMD patients than in controls. None of the co-variables expressed a significant effect on the tested cytokines. Only IL-1a and IL-17 showed a statistically significant difference between groups (improved, unchanged, deteriorated) as determined by one-way ANOVA. Patients with increased macular thickness during treatment showed significantly lower levels of IL-17 compared to improved cases and to unchanged cases (p = 0.004, 0.03 respectively, Dunnett's T3 post hoc multiple test). TNF-α was significantly higher in improved cases compared to deteriorated cases (p =0.03, Dunnett's T3 post hoc multiple test). IL-17 was a significant predictor for macular oedema using linear regression (β = -0.888, p <0.05).

Conclusion: Elevation of IL-1α, IL-1β, IL-4, IL-5, IL-10, IL-13, and IL-17 in the serum of AMD patients supports the hypothesis of AMD as an inflammatory disease. Patients with high IL-17 and TNF-α serum levels were more likely to have a favourable course under VEGF therapy. These cytokines may be used as easy-to-obtain biomarkers.