The humanized anti-C5 antibody eculizumab, which prevents the cleavage of C5 and subsequent formation of the terminal complement complex (TCC, C5b-9) and generation of pro-inflammatory anaphylatoxin C5a, represents the first approved complement-related drug and is currently discussed as therapeutic substance in rheumatoid arthritis [184]. This evidence concerns the gene C5 and rheumatoid arthritis.