TFRC and systemic lupus erythematosus: Besides, compared to baseline, Tfr subsets:Tfh subset ratios in SLE were dramatically increased, including CXCR5+PD-1low Treg/Tfh (P<0.001), CXCR5+PD-1high Treg/Tfh (p<0.001), CXCR5+PD-1low Treg/Tfh17 (P<0.001), and CXCR5+PD-1high Treg/Tfh17 (P<0.001).