Evaluation of serum and ocular levels of membrane attack complex and C-reactive protein in CFH-genotyped human donors

There is a considerable body of evidence demonstrating a link between the membrane attack complex (MAC) and age-related macular degeneration (AMD), and between C-reactive protein (CRP) and AMD. Both the MAC and the monomeric form of CRP (mCRP) accumulate within the choriocapillaris in AMD. However, the precise contribution of these species to AMD pathophysiology has not been fully elucidated. We sought to directly assess CRP and MAC levels between human serum and ocular tissues from the same CFH Y402H genotyped donors using ELISA of serum and RPE/choroid proteins. The Y402H polymorphism was associated with significantly increased MAC in RPE/choroid samples, but not in the serum, in a previously unstudied cohort. While MAC levels in the choroid were independent of circulating levels, choroidal CRP was correlated to serum levels. These data provide further evidence for local activation of complement within the choriocapillaris in AMD.