Leukocyte populations in interstitial cystitis and idiopathic reduced bladder storage

Mast cells and leukocyte populations in bladder biopsies from women with interstitial cystitis (IC) or idiopathic reduced bladder storage (sensory urgency [SU]) were compared to determine whether any evidence of a common etiology between these conditions could be found.

Biopsies from 40 patients (9 meeting the National Institute of Arthritis, Diabetes, Digestive and Kidney Diseases criteria [IC] and 31 who did not [SU]) and 20 controls (having colposuspension for stress incontinence) were stained with monoclonal antibodies against leukocyte antigens and mast cell tryptase. The median cell counts from 10 high power fields were calculated and compared between cases and controls. The clinical and urodynamic data were also compared.

Nocturia (odds ratio 26.7; 95% confidence interval 3.3 to 245.5) and bladder pain (odds ratio 18.5; 95% confidence interval 1.8 to 193.1) were associated with significant odds ratios for disease (IC or SU compared with controls) in logistic regression analysis. Patients with IC were significantly older than those with SU (P = 0.05). Leukocyte populations showed only increased CD20+ cells in patients with IC compared with the others (P = 0.03).

The analysis of the clinical, urodynamic, and cystoscopic data showed no differences between patients with IC and those with SU, except for age. Nocturia or bladder pain discriminated between patients and controls. The lymphocytic infiltrate in SU is similar to that seen in IC but with fewer CD20+ cells. These data support the work of others and may indicate that SU has a common etiology with IC.