CCL2 and retinitis pigmentosa 1: Microglia activation and upregulation of inflammatory mediators such as TNFα, IL-6, IL1α, IL1β, monocyte chemoattractant proteins 1 and 2 (MCP-1, MCP-2), or platelet growth factor (PGF) are present in both patients and murine models of RP at early stages of the disease, and they are postulated to contribute to photoreceptor death [23,24,25].