C5AR1 and infectious disease: Consistent with its aberrant expression in various infectious diseases, C5aR1 is markedly upregulated at both the mRNA and protein levels in organs such as the lungs, liver, kidneys, and heart during the early stages of sepsis, which is consistent with the abnormal expression of C5aR1 in various infectious diseases (Lu et al., 2025; Wang et al., 2023c).