C5AR1 and systemic inflammatory response syndrome: In the context of SIRS, inhibiting C5 cleavage in baboons with Escherichia coli-induced sepsis with a macrocylcic compound RA101295 induced a prompt effect in reducing proinflammatory responses as early as 2 h post sepsis induction in terms of reduced circulatory levels of C3b, C5a and soluble C5b–9 and attenuated damage of the lung and kidney25.