C5AR1 and Sepsis: Previous studies have shown that C5a/C5aR1 interactions can contribute to the pathogenesis of a wide range of inflammatory and immunological diseases (e.g., ischaemia/reperfusion injury, sepsis, autoimmune disease, transplant rejection), suggesting that C5aR1-mediated excessive inflammatory response is an important pathogenic factor in those disorders (Rittirsch et al., 2008; Hashimoto et al., 2010; Peng et al., 2012; Stegall et al., 2012).