CD163 and rheumatoid arthritis: These macrophages are 27E10+, which recognises an epitope on the alarmins S100A8/9.61 These S100A8/9+ macrophages are susceptible to anti-TNF therapy54 after which they are removed by rapid efflux.26 RM3/1 (CD163) macrophages, typically found in healthy joints, are also present in RA synovium.