Intraocular cytokine profile and autoimmune reactions in retinitis pigmentosa, age-related macular degeneration, glaucoma and cataract

PURPOSE: To analyse intraocular cytokine levels and prevalence of intraocular antiretinal antibodies (ARAs) in patients with retinitis pigmentosa (RP), age-related macular degeneration (AMD), glaucoma and cataract, and correlate the results to clinical manifestations.

METHODS: We collected intraocular fluid samples from patients with RP (n = 25), AMD (n = 12), glaucoma (n = 28) and cataract (n = 22), and serum samples paired with the intraocular fluids from patients with RP (N = 7) and cataract (n = 10). Interleukin (IL)-1β, IL-1ra, IL-2, IL-6, IL-6rα, IL-7, IL-8, IL-10, IL-17A, IL-23, thymus- and activation-regulated chemokine (TARC), monocyte chemoattractant protein-1 (MCP-1), tumour necrosis factor-alpha (TNF-α), placental growth factor (PlGF) and vascular endothelial growth factor (VEGF) were measured using a multiplex assay. Antiretinal antibodies (ARA) detection was performed by indirect immunofluorescence.

RESULTS: Increasing age was associated with increasing levels of IL-6, IL-8, TNF-α and VEGF. All patient groups exhibited distinct profiles of intraocular cytokines. Intraocular levels of IL-8 were highest in patients with AMD and glaucoma. Cataract patients exhibited high intraocular levels of IL-23. Intraocular levels of IL-2, IL-6, MCP-1 and PlGF in RP patients exceeded the levels of serum, indicating intraocular production. Intraocular ARAs were found in only one patient with AMD.

CONCLUSION: Increased levels of inflammatory cytokines in intraocular fluid of patients with originally noninflammatory ocular diseases show that intraocular inflammation is involved in their pathogenesis of these entities. Moreover, we show that increasing age is associated with increasing levels of intraocular cytokines and conclude that future studies on intraocular mediators should be corrected for age of patients.