IL17A and rheumatoid arthritis: Remarkably, in RA, the receptors for IL-17 (IL-17RA and IL-17RC) are found in the synovium and are expressed on CD14+monocytes and macrophages, whereas synoviocytes bind with IL-17 to induce stimulation of further inflammation and production of IL-6 and MMPs in the synovium [61,65].