OBJECTIVE
The aim of this study was to assess the roles of plasma cytokines in diabetic retinopathy (DR) and their relationship with the severity of DR.
METHODS
This study included 59 diabetic patients and 19 non-diabetic controls. The plasma concentrations of endothelial <em>growth</em> <em>factor</em> (EGF), eotaxin, <em>fibroblast</em> <em>growth</em> <em>factor</em> 2 (FGF-2), Flt-3 ligand (Flt-3L), fractalkine, granulocyte colony-stimulating <em>factor</em> (G-CSF), granulocyte-macrophage colony-stimulating <em>factor</em> (GM-CSF), <em>growth</em>-related oncogene (GRO), interferon (IFN)-α2, IFN-γ, interleukin (IL)-1α, IL-1β, IL-1Ra, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12 (p40), IL-12 (p70), IL-13, IL-15, IL-<em>17</em>, IFN-inducible protein-10 (IP-10), monocyte chemoattractant protein (MCP)-1, MCP-3, macrophage-derived cytokine (MDC), macrophage inflammatory protein (MIP)-1α, MIP-1β, sCD40L, sIL-2Rα, transforming <em>growth</em> <em>factor</em> (TGF)-α, tumor necrosis <em>factor</em> (TNF)- α, TNF-β, and VEGF were measured with Luminex multiplex bead immunoassay. The levels of these cytokines were investigated according to the DR stage.
RESULTS
The plasma level of ten cytokines-MCP-1, IL-6, IL-7, IL-9, IL-13, IL-15, IL-<em>17</em>, sCD40L, sIL-2Rα and TNF-β-increased significantly in the diabetic group compared to the controls. The Flt-3L, IL-1Ra, IL-3, IL-5, and IL-12 (p40) levels were lower in the diabetic group than in the control group. The TNF-α plasma level was significantly elevated in patients with proliferative diabetic retinopathy (PDR) compared with the levels in patients with non-proliferative diabetic retinopathy (NPDR) and patients with no apparent diabetic retinopathy (NDR).
CONCLUSIONS
TNF-α might be involved in the progression of DR, especially in the pathogenesis of PDR. TNF-α is a potential cytokine for the prognosis of DR and might act as a therapeutic target in DR.