However, the significant inhibitory activity of bOmCI saturated with LTB4 (bOmCI-LTB4), which specifically inhibits C5 activation by classical and alternative C5 convertases (C3bC2C3b and C3bBbC3b, respectively) and has no effect on C5 activation by non-C proteases, indicates that C5 activation directly mediated by C5 convertase, which is present and active in BALF (51, 52), has a significant functional role in IC-ALI. Here, C5 is linked to acute respiratory distress syndrome.