ELEVATED MAST-CELL TRYPTASE IN THE URINE OF PATIENTS WITH INTERSTITIAL CYSTITIS

Objective To investigate the number of tryptase positive bladder mast cells and the level of urine tryptase in interstitial cystitis (IC), a bladder disorder which occurs mostly in women and is characterized by suprapubic pain, frequency and nocturia. Patients and methods Bladder biopsies from 37 women with IC and 15 control women with other bladde r conditions (age range 18-63 years) were obtained during diagnostic b ladder distension and frozen immediately. Mast cells positive for tryp tase were identified by immunohistochemistry and evaluated by light mi croscopy. Tryptase was measured by solid phase radioimmunoassay in uri ne samples, collected immediately (spot) and during a period of 24 h, obtained from normal women volunteers, controls and patients with IC. To adequately quantify tryptase, the physiologically active tetramer w as dissociated to inactive monomers with supersaturated NaCl (6.0 M), and then dialysed. Results The patients' spot urine sample tryptase le vels were indistinguishable from those of controls, which included the normal women volunteers. However, the tryptase levels in 24 h urine s amples were greatly elevated only in patients with IC, both before (P< 0.005), and especially after NaCl treatment and dialysis (P<0.001). Co nclusion These results indicate that the tryptase levels of 24 h urine samples, combined with methyl-histamine levels and the clinical crite ria presently used, may possibly help to better identify TC.