To further assess the complement activation at the protein level in the vitreous humor of patients with posterior uveitis, a western blot was performed for CFH and C3 in patients with non-infectious posterior uveitis and non-inflammatory controls, and a lower expression of CFH protein was observed in PU patients as compared to the controls (CFH- PU, 3199 ± 548; controls 13605 ± 1244 *p = 0.04); whereas a higher expression of C3 was observed in patients as compared to controls (C3- PU, 17027 ± 1011; controls 7510± 454 p= 0.04). This evidence concerns the gene C3 and posterior uveitis.