IL17A and infection: The protective effects of IL17 more generally in infection beyond urinary tract infections (UTIs) are mediated by several mechanisms; IL23-induced IL17 can regulate granulopoiesis via G-CSF and increase peripheral neutrophilia (Parsonage et al., 2008; Stark et al., 2005), and IL17 also has important effects on monocyte recruitment and macrophage function (Silverpil et al., 2011; Veldhoen, 2017).