With regard to diabetic retinopathy, Rangasamy et al showed that the expression of MCP-1 was increased in the retina of diabetic rodents [9], that this expression was accompanied by greater-than-normal numbers of perivascular monocytes in the retina, and that the deletion of Mcp-1 (also known as Ccl2) resulted in significant reduction of monocyte infiltration [9]. This evidence concerns the gene CCL2 and diabetic retinopathy.