CXCR5 and rheumatoid arthritis: However, UC-MSCs did not inhibit the generation of CD4+CXCR5−T cells, and upregulated them both in RA and HC PBMCs (Supplementary Fig. 3), suggesting that CD4+CXCR5+T cells not CD4+CXCR5−T cells might be specifically susceptible to UC-MSCs-mediated suppression.