Elevated Levels of Serum IL-17A Secondary to Repeated Intravitreal Injections of Aflibercept in Treatment-Naive Patients with Neovascular Age-Related Macular Degeneration

We evaluated the effect of three monthly intravitreal injections of aflibercept on the serum concentration of interleukin 17A (IL-17A), monocyte chemoattractant protein 1 (MCP-1/CCL2), vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) in treatment-naive patients with neovascular age-related macular degeneration (nAMD). Twenty-two eyes of twenty-two patients with nAMD scheduled for the initial loading phase of intravitreal aflibercept (2 mg/0.05 mL) were included. Serum VEGF, PlGF, MCP-1/CCL2 and IL-17A levels were determined four times in each individual-just before the first injection, 2-3 days after the first injection, just before the third injection, and then 2-3 days after the third aflibercept injection. A statistically significant difference was found between the serum PlGF and IL-17A levels measured before the first injection and after the initial loading phase, with a mean value (MV) of 440.884 vs. 302.151 (p= 0.023) for PlGF and MV = 139.088 pg/mL vs. 151.233 pg/mL (p= 0.016) for IL-17A, respectively. There were no statistically significant differences for VEGF and MCP-1/CCL2 between any of the compared measurements. We reveal that repeated injections of aflibercept promote an increase in serum IL-17A concentration, which may lead to a systemic inflammatory response mediated by IL-17A, but not by MCP-1.