These findings suggest an essential role of Ccr2 in the pathogenesis of microglia-mediated degenerative disease, which is consistent with previous reports that Ccr2 is required for efficient recruitment of peripheral monocytes to the pathological tissues in autoimmune uveitis,46 retinitis pigmentosa,48 autoimmune encephalitis,47 and atherosclerosis.49 This evidence concerns the gene CCR2 and retinitis pigmentosa.