IL17A and cystitis: Previous studies have largely approached the question of which pathways, cytokines, or immune cells are important in bladder infection in a hypothesis-driven manner, measuring or knocking out a favored cytokine (like IL17), or a particular cell type based on prior knowledge cytokine (Jones-Carson et al., 1999; Sivick et al., 2010; Zychlinsky Scharff et al., 2019).