CD68: Potential Contributor to Inflammation and RPE Cell Dystrophy.

Age-related macular degeneration (AMD) is the leading cause of visual impairment in the elderly in developed countries. It is a complex, multifactorial, progressive disease with diverse molecular pathways, including inflammation, regulating its pathogenesis. The myeloid marker CD68 is a protein highly expressed in circulating and tissue macrophages. Recent observations of immune markers in human AMD tissues have varied with some finding ectopic RPE cells in advanced AMD and others noting negligible numbers of CD68-positive cells. Additionally, animal models of retinal degeneration have shown upregulation of CD68, in a protective population of retinal microglia. Herein, we review the potential role of CD68 in regulating RPE health and inflammation in the sub-retinal space and discuss observations on its localization in a mouse model that presents with AMD-like features.