This minor role of Ccl2 on the RD8 retinal degeneration seems consistent with our previous observation that Ccl2 deficiency does not lead to a significant associated age-related retinal degeneration despite an accumulation of subretinal, dysfunctional macrophages [40] and may be explained by a minor role of Ccl2 in this process or by a compensatory effect of other chemokine ligands that can bind to and activate CCR2 [19]. Here, CCR2 is linked to retinal degeneration.