C3 and retinal degeneration: In the blood of miR-223–/– mice, circulating CD11b+ cells showed an increase in C3 and Il-1β, which are both critically linked to macrophage-mediated retinal degeneration (Rutar et al., 2011a; Hu et al., 2015; Eandi et al., 2016; Natoli et al., 2017a, b).