The majority of CD40-positive cells were LSECs, and the CD40-positive area was significantly more prominent in the SMD group with high serum IFNγ levels than in the NSMD group (Fig. 5), implying that the IFNγ-CD40 axis might be clinically crucial for the microcirculatory disturbance in ALI. This evidence concerns the gene IFNG and acute respiratory distress syndrome.