CD68 and rheumatoid arthritis: Furthermore, a study in 42 patients with untreated undifferentiated inflammatory seronegative arthritis reported that 6 patients who differentiated during the follow up (2 RA, 2 PsA, and 2 pSpA) had significantly higher synovial CD68+ macrophage scores compared with patients remaining undifferentiated, in line with our results (22).