The Western blotting results identified no significant change in C1q and C4b in the vitreous of PDR compared to no-DM controls (C1q–PDR: 1.81 ± 0.44, controls: 1.32 ± 0.38 p = 0.3; C4b–PDR: 1.39 ± 0.4, control 1.08 ± 0.2, p = 0.5) (Figures 2A,B,D). This evidence concerns the gene C4B and diabetes mellitus.