Transcriptome analysis showed that signature genes for PD-1hiCXCR5−CD4+ T cells of RA, such as CXCL13, SH2D1A, CCR2, TIGIT, MAF, and TOX5, were upregulated in the TGF-β plus IL-1β and TGF-β plus IL-6 groups (Supplementary Table 1). Here, CXCL13 is linked to rheumatoid arthritis.