In addition, p-STAT1 and iNOS levels are decreased in the lungs of human D-MSC-cP1P-treated mice.196 Besides, MSCs primed with BMP2 increase the level of IDO1, and the number of Foxp3+CD25+ Tregs among CD4+ cells is further increased in ALI mice.197 PGE2-primed P-MSCs reduce the severity of ALI in mice by modulating macrophage polarization and cytokine production.198. Here, IDO1 is linked to acute respiratory distress syndrome.