The role of C5aR2 in ARDS mouse models was further investigated and confirmed in a subsequent study with a mouse model of C5aR2 receptor deficiency (C5L2−/−) which showed that administration of LPS significantly increased airway edema and hemorrhage, as well as BALF and lung tissue neutrophil counts in C5L2−/− mice in comparison with wild type animals. This evidence concerns the gene C5AR2 and acute respiratory distress syndrome.