Our results show that compared to Tph cells, cTfh cells express higher levels of Bcl6 and BATF (Figure 2A), ICOS, CD40L, CXCL13, IL-4 and IL-21 (Figure 2B) in RA patients and HC, which indicate that cTfh cells have a more potent ability for B-cell recruitment and assistance than Tph cells. Here, IL21 is linked to rheumatoid arthritis.