CD4 and rheumatoid arthritis: Compared with the OA samples, the RA synovial tissues consisted of a higher proportion of 7 immune cells (plasma cells, CD8+ T cells, CD4+ naive T cells, activated memory CD4+ T cells, follicular helper T cells, T cells gamma delta, and M1 macrophages), whereas 4 immune cells (T cells regulatory, M2 macrophages, dendritic cells resting, and mast cells resting) were found in relatively lower proportion (Figure 7).