CD40 and rheumatoid arthritis: Healthy (blue), IAR (orange), and RA (red) synovial tissue macrophages can be distinguished based on these clusters with the two CD40-expressing CD206 “C1/2” observed in IAR and RA synovial tissue and with the CX3CR1-expressing CD206 macrophage C3 unique to healthy synovium (Fig. 7C).