CD4 and rheumatoid arthritis: The expression of pSTAT3 in CD4+CXCR5+ Tfh cells was highest in the active RA group (51.3 ± 3.4%), followed by that in the inactive RA group (39.3 ± 1.9%) and the control group (29.7 ± 1.7%) (P < 0.05, Fig. 2d).