title: Are mast cells still good biomarkers for bladder pain syndrome/interstitial cystitis?
abstract: OBJECTIVE
  ESSIC identifies mast cell infiltrates of detrusor muscle as a diagnostic criterion for bladder pain syndrome/interstitial cystitis. However, an increased mast cell count is also characteristic of overactive bladder syndrome. The lack of uniformity in mast cell detection methods hampers data comparison. Using state-of-the-art techniques we investigated whether mast cells differ among bladder conditions.
  
  
  METHODS
  We analyzed bladder biopsies from 56 patients, including 31 with bladder pain syndrome/interstitial cystitis with (12) or without (19) Hunner lesions, 13 with overactive bladder syndrome and 12 without bladder symptoms to determine the quantity, location, distribution and activation of mast cells using immunohistochemistry with anti-mast cell tryptase. Patients were allocated to study groups by key bladder symptoms commonly used to define conditions (pain and major urgency).
  
  
  RESULTS
  Subepithelial mast cell localization (p <0.001) and an increased detrusor mast cell count (p = 0.029) were characteristic of bladder pain syndrome/interstitial cystitis with Hunner lesions. The optimal cutoff of 32 detrusor mast cells per mm(2) achieved only 68% accuracy with 38% positive predictive value. No difference was observed between bladder pain syndrome/interstitial cystitis without Hunner lesions and overactive bladder syndrome. Patient groups differed in lymphocyte infiltration (p = 0.001), nodular lymphocyte aggregates (p <0.001) and urothelium integrity (p <0.001).
  
  
  CONCLUSIONS
  Subepithelial mast cell distribution was characteristic of bladder pain syndrome/interstitial cystitis with Hunner lesions. Detrusor mastocytosis had poor predictive value for bladder pain syndrome/interstitial cystitis. Mast cell assessment did not distinguish bladder pain syndrome/interstitial cystitis without Hunner lesions from overactive bladder syndrome.
authors.affiliation: Department of Gynecology and Obstetrics, Cantonal Hospital Frauenfeld, Frauenfeld, Switzerland; Institute of Pathology (SR), Medical University Graz, Austria. Electronic address: marianne.gamper@stgag.ch.
authors.forename: Marianne
authors.initials: M
authors.lastname: Gamper
authors.affiliation: Department of Gynecology and Obstetrics, Cantonal Hospital Frauenfeld, Frauenfeld, Switzerland; Institute of Pathology (SR), Medical University Graz, Austria.
authors.forename: Sigrid
authors.initials: S
authors.lastname: Regauer
authors.affiliation: Department of Gynecology and Obstetrics, Cantonal Hospital Frauenfeld, Frauenfeld, Switzerland; Institute of Pathology (SR), Medical University Graz, Austria.
authors.forename: JoEllen
authors.initials: J
authors.lastname: Welter
authors.affiliation: Department of Gynecology and Obstetrics, Cantonal Hospital Frauenfeld, Frauenfeld, Switzerland; Institute of Pathology (SR), Medical University Graz, Austria.
authors.forename: Jakob
authors.initials: J
authors.lastname: Eberhard
authors.affiliation: Department of Gynecology and Obstetrics, Cantonal Hospital Frauenfeld, Frauenfeld, Switzerland; Institute of Pathology (SR), Medical University Graz, Austria.
authors.forename: Volker
authors.initials: V
authors.lastname: Viereck
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D002452:Cell Count; D018856:Cystitis, Interstitial / Q000473:pathology*; D003937:Diagnosis, Differential; D006801:Humans; D008407:Mast Cells; D008875:Middle Aged; D011446:Prospective Studies; D001743:Urinary Bladder / Q000473:pathology*; D053201:Urinary Bladder, Overactive / Q000473:pathology
keywords: cystitis; diagnosis; interstitial; mast cells; overactive; pain; urinary bladder