CD4 and rheumatoid arthritis: Compared with the joint synovium of normal individuals, there were significant differences in 14 types in the joint synovium of RA patients, including B cells memory, plasma cells, CD8 T cells, resting CD4 T cells memory, activated CD4 T cells memory, follicular helper T cells, regulatory T cells (Tregs), γδT cells, activated natural killer cells, monocytes, M1 macrophages, M2 macrophages, resting dendritic cells, and activated mast cells (Fig 8A).