PTGS2 and cystitis: Taken together, these prior studies and our findings here elucidate an interesting dichotomy: whereas in Resolved mice, moderate, TNFɑ-mediated neutrophil recruitment to the bladder and subsequent exfoliation of IBC-containing urothelial cells allows for the clearance of infection, in Sensitized mice prolonged TNFɑ-signaling, coupled with COX-2 mediated transmigration of neutrophils across the bladder epithelium, exacerbates inflammation and mucosal wounding to promote severe acute cystitis.