S100A9 and rheumatoid arthritis: These included transcripts for pro-inflammatory mediators Ccl3, Cxcl1, Ccl2, Ccl9, Nos2, Arg1, Il1m, Il1b, and Osm, their regulators S100a9 [46], Slamf6 and Il1r2, the C-type lectins Clec5a and Clec4e [47], as well as Lcn2 associated with bone damage in RA [48,49].