TRERF1 and systemic lupus erythematosus: Rapa-SLE-EVs were compared with EVs derived from MSCs from MSCs cultured with EV-depleted fetal bovine serum (FBS-EV), EVs from MSCs cultured with rapamycin-treated FBS (Rapa-FBS-EV), and EVs exposed to SLE serum without rapamycin (SLE-EV).