C5 and age-related macular degeneration: In moving from normal through early and into late-stage AMD there is progressive up-regulation in the macula retina of complement genes associated with the CP, including all components C1Q, the C1Q-associated activators C1R and C1S, C2 and C3, and the initial members of the membrane attack complex C5, C6 and C7. The soluble complement inhibitors CFH and SERPING1 are also up-regulated, as well as the membrane-bound regulator of the C5b-9, CD59, perhaps reflecting regulatory feedback accompanying complement activation.