It has also been suggested that the C5a/C5aR1 axis could contribute to kidney infection through two pathways: i) mediating excessive inflammatory responses and ii) upregulating the expression of the mannosyl residue (Man) (the potential ligand for type 1 fimbriae of UPEC) on the luminal surface of the renal tubular epithelium which promotes UPEC adhesion/colonization in the kidney (Li et al., 2017; Song et al., 2018). The gene discussed is C5AR1; the disease is pyelonephritis.