C6 and atherosclerosis: Already in the late 1970s Geertinger et al could show that C6 deficiency, for instance, protects cholesterol-fed rabbits from atherosclerosis (Geertinger and Sorensen, 1970) and inhibition of C5a or its receptor C5aR1 (CD88) reduces atherosclerosis in murine models (Shagdarsuren et al., 2010; Manthey et al., 2011).