These results indicate that the C5a-C5aR1 axis plays an important role in the occurrence of ALI induced by influenza virus infection, and that the use of anti-C5aR1 antibodies can suppress the hyperactive immune response induced by viral infection and effectively inhibit viral replication in the lung, thereby attenuating inflammatory responses and reducing lung injury in influenza [97,98]. Here, C5AR1 is linked to acute respiratory distress syndrome.