With the CD163 staining, there is a trend toward increase numbers of CD163+ macrophages (Fig. 5A,B: 3 out of 5 RA donors have > 50 CD163+ cells/high-power field [HPF; 40X] compared with just 2 out of 7 controls, although the number of donors tested is too limited to be conclusive). Here, CD163 is linked to rheumatoid arthritis.