TNF and acute respiratory distress syndrome: EVs have emerged as a key factor responsible for the therapeutic effects of MSCs in lung injury, accumulating evidence, including our own studies, demonstrates that EVs are able to recapitulate many of the effects of the cell therapy.17 29 50 51 In agreement with these findings, in the present study, EVs but not EV-free MSC CM recapitulated the effect of the MSC co-culture on macrophage secretion of TNF-α and IL-8 and activation of pSTAT5-SOCS1 axis in the presence of LPS and, most importantly, when exposed to the plasma from patients with ARDS (figures 2 and 3).