CD68 and rheumatoid arthritis: M1 and M2 macrophages also play a role in PVNS and RA, the detection of macrophage marker (CD68/CD163) expression showed that macrophage-positive synoviocytes were found in both RA and PVNS, In RA, CD68/CD163+ synoviocytes were most often found in the synovial lining layer, but in PVNS, they were more spread out (Sehgal et al., 2021).