Among the many different substances encountered in the drusens of patients with AMD are the complement proteins C1q, C3, C4, C5, CFH, membrane cofactor protein, decay accelerating factor, the anaphylatoxins C3a and C5a, immunoglobulins, CRP, cholesterol esters, and low-density lipoprotein [18,19]. Here, C4A is linked to age-related macular degeneration.