The quantification of neutrophils (Ly6G+ cells) infiltration into the kidneys of wild type, C5aR1−/− and C5aR2−/− mice is shown in Figure 4E. These observations were very interesting but a bit perplexing since one of the roles of C5a in the host response to pathogens is to contribute to the recruitment of neutrophils to the site of infection. Here, C5AR1 is linked to infection.