Intriguingly, upregulation of these proteins does not appear to be specific for a particular inflammatory disease, as S100A8 and S100A9 have been implicated in a number of seemingly unrelated inflammatory conditions, including rheumatoid arthritis [70–74], CD [27, 28], systemic lupus erythematosus [75–78], cardiovascular diseases [79–81], psoriasis [82, 83], MS [84, 85], and others. Here, S100A9 is linked to rheumatoid arthritis.