Meanwhile, we also noticed that infiltration of immune cells such as activated B cell, activated CD4 T cell, activated CD8 T cell, activated dendritic cell, immature B cell in ACPA-positive RA synovium were more highly than those in ACPA-negative RA synovium, which suggested that the degree of uncontrolled autoimmune response of ACPA-positive RA patients is more severe than that of ACPA-negative RA patients. Here, CD4 is linked to rheumatoid arthritis.