TGFB1 and acute respiratory distress syndrome: Compared with that in the lungs of the ARDS group, the number of CD4+ T cells increased significantly in the lungs of the LPS + mBM-MSC, LPS + mBM-MSC-NC, and LPS + mBM-MSC-TGFβ1 groups (p < 0.05, Fig. 5a).