CXCL8 and proliferative diabetic retinopathy: Previously, we demonstrated that not only vascular endothelial growth factor (VEGF) but also other inflammatory cytokines such as interleukin-8 (IL-8), MCP-1, MIP-1β, and IP-10 were elevated in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR) and retinal vein occlusion (RVO) [4].