Concerning IL-6, this is further supported by studies showing that the serum levels of IL-6 correlate with those of C-reactive protein and rheumatoid factors, as well as the degree of joint destruction [52] and that the disruption of IL-6 signalling by receptor-blocking antibodies shows clinical efficacy in RA in phase II clinical trials [2,53,54]. Here, IL6 is linked to rheumatoid arthritis.