Both anti-C5 monoclonal antibodies and C5aR1 antagonists were developed and used as therapeutic agents to attenuate tissue injury in various rodent disease models, including kidney ischemia/reperfusion injury, intestine ischemia/reperfusion injury, sepsis, spinal cord injury, CNS lupus, hypertension, AD, intracerebral hemorrhage, and ischemic stroke [270, 339, 340, 416-423]. Here, C5AR1 is linked to Alzheimer disease.