CD40LG and diabetic retinopathy: Overexpression of IL-1β and TNF-α in retinal microglia and macrophages, and of CD40 ligand, a member of the TNF-α superfamily, in Müller cells, endothelial cell, and microglia is an early feature of diabetic retinopathy and the main factor responsible for retinal inflammation in experimental models of diabetic retinopathy [50].