As a normal response to infection, neutrophils recognize chemokines including the bacterial product N-formyl-methionyl-leucyl-phenylalanine (fMLP), complement 5a (C5a), and lipid molecules Leukotriene B4 (LTB4) and C-X-C motif chemokine ligand 8 (CXCL8), and then enter the site of infection through mobilization, rolling, adhesion, migration, and chemotaxis (14). The gene discussed is C5AR1; the disease is infection.