After treatment with exosomes, JKAP-knockdown BMSC-exosomes reduced JKAP expression in RA CD4+ T cells compared to Scramble BMSC-exosomes (p < 0.05), while JKAP-overexpression BMSC-exosomes elevated it (p < 0.01) (Figures 2C–2E). Here, CD4 is linked to rheumatoid arthritis.