C5AR1 and Sepsis: The complexity of C5AR1-induced effects on different immune functions and systems is reflected by the fact that even though C5a–C5AR1 interaction is associated with the preservation of neutrophil innate immune functions (chemotaxis, phagocytosis, respiratory burst) and attenuation of the inflammatory reaction, excessive interaction of C5a–C5AR1 may result in harmful effects including the paralysis of neutrophil function during extreme inflammatory reactions such as sepsis (47, 48).