C5AR1 and pyelonephritis: The findings presented in this study, coupled with the findings of our previous studies in pyelonephritis (Choudhry et al., 2016; Li et al., 2017; Song et al., 2018), highlight pathogenic roles for C5aR1 in UTI and open up a new avenue for therapeutic targeting in human UTI, as therapeutic reagents targeting the C5a/C5aR1 axis suitable for clinical use are available (Zelek et al., 2019; Lee, 2022).