Compared with HC M1 macrophages, Tfh cells, the numbers of memory activated CD4+ T cells, and plasma cells were significantly higher in RA synovial tissues, while those of regulatory T cells, activated dendritic cells, activated NK cells, memory resting CD4+ T cells, resting mast cells, and activated mast cells were significantly lower in RA synovial tissues. This evidence concerns the gene CD4 and rheumatoid arthritis.