Our findings demonstrate that the protective effect of MSC-MVs against BLM-induced lung toxicity was achieved through the inhibition of the ERK1/2 signaling pathway, leading to the suppression of CCL2 expression and subsequent modulation of monocyte-macrophage migration, thereby establishing a theoretical basis for the effect of MSC-MVs in PF. The gene discussed is MAPK3; the disease is pemphigus foliaceus.