Specifically, we constructed CD38 antigen receptor membrane-modified HUCMSC-EVs by transfecting MSCs with a lentivirus loaded with a CD38 antigen receptor−CD8 transmembrane fragment fusion plasmid to target and rejuvenate senescent type 2 alveolar epithelial cells, which express a high level of CD38 (a marker of senescent cells) and play a pivotal key role in age-associated pulmonary fibrosis [234]. Here, CD38 is linked to pulmonary fibrosis.